An Educational Hands-On Demonstration Program
for Groups of 25 Students in Grades 3-6
Prepared by the
National Chemistry Week Planning Committee
of the
American Chemical Society
Cleveland Section
for
National Chemistry Week 2014
Called
Tour the Candy Sense-ation Lab
Overview
Join us for a tour of the Candy Sense-ation Lab. Chemistry makes candy more appealing to
the senses! What makes candy taste good? Natural and artificial sweeteners! which we can
distinguish using a chemical reaction. There are other tastes that enhance our experience
of candy....like sourness, which we will measure. Novel textures make candy feel cool...we
will make gummy worms. Edible dyes make candy look colorful and interesting to explore.
And candy can also sound fun, due to chemical reactions. As Willy Wonka says about
touring his Inventing Room: 'Enjoy yourselves...' As in this room, we won't be eating, but
we will be enjoying candy creations enhanced by chemistry.
Note: After Sept., please see our Cleveland Section web site (p. 3) for an Errata sheet.
Table of Contents
List of Experiments……………………………………………..
How Experiment Write-ups are Organized…………………
Websites of Interest…………………………………………….
Checklists…………………………………………………………
Supplies for Demonstrator to Bring from Home.………….
Supplies Included in Your Kit…………………………………
Experimental Setup…………………………………………….
The Program…………………………………………………….
Opening Discussion…………………………………………
Background for the Demonstrator (only)………………….
Introduction to the Program for the Students………………..
Experiments………………………………………………….
Closing Session…………………………………………………
Cleanup & Return Procedures…………………………….....
Appendices………………………………………………………
Page
2
2
3
4
9
10
13
17
17
18
19
20
40
41
43
Acknowledgments
The National Chemistry Week (NCW) program of the Cleveland Section of the American
Chemical Society (ACS) began in 1994 with an idea to put together a scripted program that
could be performed at any local school or library. This idea has expanded to become the
centerpiece of the Cleveland Section's NCW activities. On numerous occasions it has received
national recognition from the American Chemical Society, including the ChemLuminary Award
for Outstanding On-Going NCW Event, awarded in 2012. In 2014 the Cleveland Section’s
volunteers will perform at least 40 demonstrations at libraries, schools, and other public sites.
Our NCW efforts reach many students each year because of various sponsors who have donated
money, materials and/or services to the Cleveland Section specifically for National Chemistry
Week. We would like to especially thank our partners at the Cuyahoga County Public Library
(CCPL) for creating and distributing flyers and providing the facilities for this program. We also
extend our sincere thanks to John Carroll University for hosting GAK Day (Grand Assembly of
Kits Day) and our Dress Rehearsal, to Graftech International for generously providing supplies,
to NASA Glenn Research Center which printed this and other documents, and to our Cleveland
Section of the ACS for its financial support.
Last and most important, we thank all the volunteers who donated their time and expertise. This
library/school program and other NCW events are the result of the hard work of many dedicated
and talented volunteers. It all starts with our local section NCW Planning Committee. The
Committee recommends, tests, and reviews activities & experiments; writes this script including
a story line to hold the attention of children; collects supplies and materials; prepares the kits;
recruits sponsors and volunteers; contacts libraries and schools; and schedules demonstrations.
Committee members include Betty Dabrowski, Bob Fowler, Liz Herbell, Danielle Kuhn, Lois
Kuhns, Helen Mayer, Vince Opaskar, Marcia Schiele, Ed Schneider, Shermila Singham and
Natalie Zarlenga. Additional credit and thanks is given to the many GAK Day volunteers
including students from Baldwin Wallace, Case Western Reserve, Cleveland State and John
Carroll universities who gave up a Saturday in September to help count, measure and assemble
all of the necessary materials for our demonstration kits. A final thank you goes out to the
dozens of dedicated chemistry professionals and scientists who lead the presentations and
activities in schools, libraries, and other public locations. Without them there would be no
Cleveland Section NCW program.
Introduction and Checklists
Presenter’s Guide
List of Experiments
A. Taste
1. Sugared and Sugar-Free Candy …………………………… p. 20
2. Why are Some Candies Sour?……………………………… p. 24
B. Texture/Feel
3. Making Gummy Worms …………………………………… p. 26
C. Sight
4. The Many Colors of Candy………………………………… p. 30
5. M&M® Wheel & Floating M’s……………….……………. p. 33
D. Sound
6. Pop Rocks Rock…………………………………………..… p. 36
7. A Candy Fountain ……………………………………….… p. 38
How Experiment Write-ups are Organized
Each experiment’s write-up is presented as follows:
1.
2.
3.
4.
5.
Experiment Purpose & General Methodology: Background on the Experiment.
Introduce the Experiment: Suggestions for introducing the experiment to the students.
Performance Details: How to perform the Experiment in detail.
Conclusions: Suggested conclusions to draw from the Experiment.
Technical Information (for the Demonstrator): This information is background info
to help you understand what we’re trying to accomplish technically in the experiment. It
certainly isn’t intended that you give these technical details to the students unless the
students ask or request it.
Presentation Overview
This section describes the basic presentation technique used during the demonstrations. This is a
guideline only as the technique may vary for some experiments. Make sure you follow the
instructions given in each experiment. The program this year consists of 7 experiments.
•
For most experiments your demonstration and the student’s hands-on work are nearly
simultaneous. You will lead them as they perform the experiment.
•
Please encourage multiple students to assist when an experiment is done as a group at a table.
•
Five experiments will be done by all students. One other experiment (No. 1) is a group
experiment to be shared by all or some of the students at the table and another (No. 7) is a
demonstration only.
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Introduction and Checklists
Presenter’s Guide
VOLUNTEERS
This year the NCW Committee will be videotaping the annual “Dress Rehearsal” demonstrations
as they are presented at JCU. We’ll post the link to this video (most likely on YouTube) on the
Volunteers page at our web site at http://www.csuohio.edu/sciences/dept/cleveland_acs/NCW/ as
soon as we know. It will demonstrate this year’s NCW program in detail and may be viewed by
anyone interested in hosting our program. Alternately, this script provides enough detail for a
teacher or parent to perform the presentation. The Cleveland ACS and NCW Committee do not
require background checks on its volunteers nor do we require formal educational/teaching
experience from all of its volunteers.
MAKE SURE TO FOLLOW ALL DIRECTIONS IN EXPERIMENTS
If experiments have special safety concerns due to the materials being used, they will be listed in
the section for that experiment. Eye protection should be worn at all times by everyone, and
students should be specifically told to not touch their eyes. There are very few purchased
chemicals in the program this year, and some are household chemicals. If exposure should
occur, flush with water and report the incident to the librarian and parent. For skin contact,
washing with soap and water will suffice. Websites for where to obtain a Material Safety Data
Sheet (MSDS) are listed in the Appendix A and also on our NCW website below.
For information about the American Chemical Society’s NCW safety guidelines, visit
www.acs.org/portal/Chemistry?PID=acsdisplay.html&DOC=ncw%5Csafetyguidelines.html.
Websites of Interest
Cleveland Section:
http://www.csuohio.edu/sciences/dept/cleveland_acs/NCW/
National American Chemical Society’s “National Chemistry Week” website:
www.acs.org/ncw
Note: At the time of this printing, the location of the video on the
Internet demonstrating this 2014 Candy Program had not yet been
resolved although YouTube is likely. If, and as soon as it is resolved,
we’ll post the link to the video on our NCW page of the Cleveland
Section web site (first one, above) under the Volunteers tab.
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Introduction and Checklists
Presenter’s Guide
Check Lists
Activities To Do Well Before the Day of the Demonstration
Contact the Children’s Librarian and
• Verify the date and time of your 1-hour program
• Also schedule AT LEAST an hour before and an hour after your program
for set-up and clean-up. Modify the setup time appropriately depending on
how familiar you are with the materials in your kit and if you will have an
assistant. Make sure the room will be available. Ask if someone will be
available to assist with the Program: Setup, Demonstration and Cleanup.
Read through this script to familiarize yourself with the experiments and verify
that you have all the items as listed in the kit contents.
If you’re using a pre-printed hard copy of the script, obtain the Script
Errata/Addendum Sheet which will be posted on our web page.
Contact Bob Fowler at [email protected] with any questions.
Completed?
Collect the materials you need to bring with you to the demonstration. A
materials list is on page 9. The librarian may be able to provide some of the items,
but you need to call to verify that—do not assume that the library has what you
need. Do NOT assume you can easily obtain water in the library; at some sites
faucets are close to the sink bottom and allow little room for easily filling bottles or
cups.
While not necessary, it’s recommended that you ask a friend to assist, and/or
contact the Head Children’s Librarian well in advance to request a student
assistant or librarian to be your assistant. Having someone available to help setup the room before the program and collect trash as the program progresses can
help keep supplies organized. That person can also assist if individual students
need help with or have questions about the experiments.
If you wish to add other experiments or demonstrations into your program, you
must contact the Head Children’s Librarian through your local librarian ahead of
time to get approval. Be careful and think “safety first”. Neither the NCW
Committee nor the Cleveland ACS approves of any experiments added to this
program, and you are responsible for your own actions.
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Activities To Do about ONE WEEK BEFORE your program
Contact the Head Children’s Librarian who is helping you to coordinate our
program:
 VERIFY that they limited registration to 25 students.
 Ask the room to be arranged with 5 student experiment tables with 5 chairs each,
an additional front table for the presenter and a small side table/area for literature,
photo permission forms, and goggles.
 If they’re not already chemical/liquid resistant, ask for all the experiment tables
to be covered with newspapers and for extra paper towels for each table. Otherwise
take newspaper and do this during setup.
National Chemistry Week 2014 - Cleveland Section
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Introduction and Checklists
Presenter’s Guide
 Ask about availability of demonstration materials from the list on page 9 (ex.
paper towels, newspaper).
 Invite the librarian and/or student assistant to stay for the entire program. (They
might even offer to be an assistant if given the opportunity.)
Activities To Do AT LEAST ONE DAY BEFORE the Demonstration
Read over the experiments a few times and become familiar with them. Our
program is designed for about one hour for someone who is comfortable with the
script. Practicing your presentation is very helpful.
Remove the 4 hard candies from Exp. 1. Leaving the hard candies in their original
wrappers, pulverize them with a hammer as best as you can. You might want to
cover them with a cloth before hammering them. Keep the sugared and sugarfree candies separate, return them to their respective baggies (marked “S” and
“SF”) and return these baggies to the Exp. 1 gallon bag.
Put 10 cups (2.365L) of water into your plastic jug. Add the CaCl2 pellets from the
materials for Experiment 3 to the water. When the CaCl2 pellets are dissolved, this
solution becomes the “Activator” for Experiment 3.
Experiment 5 involves an “M&M® Wheel”: 4 different colored M&M’s® are
covered in water in the four quadrants of a Petri dish. You’ll find that these color
zones don’t mix together. It’s therefore important that each student be given 4
different colored M&M’s®. It’s suggested that you remove the M&M’s®, the 25
small medicine cups and the extra sandwich-sized plastic bag from the materials for
Experiment 5. Divvy the M&M’s® up among the 25 medicine cups taking care to
make sure that each cup has 4 different colors. Then stack up these cups with the
M&M’s® in them as shown in Figure 0. Stuff a wadded-up tissue into each top cup
to prevent those M&M’s® from spilling out.
National Chemistry Week 2014 - Cleveland Section
Completed?
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5
Introduction and Checklists
Presenter’s Guide
Figure 0. Medicine Cups with M&M’s® stacked & stored in a Sandwich Bag.
Re-place this sandwich bag into the kit box where its contents won’t be crushed.
Inspect the two bottle caps included with the materials for Experiment 7. The idea
with this experiment is to create a “candy fountain”: when a Mentos® tablet is
dropped into a fresh bottle of carbonated pop, large quantities of CO2 are almost
instantaneously released. This requires that the bottles of pop in your kit not be
opened until immediately before the demonstration. When opened, the original
bottle cap must be immediately replaced with one of the two holed caps with a
Mentos® tablets secured underneath. Upon securing this holed cap onto the bottle,
the Mentos® tablet is released by pushing it down into the pop liquid with the head
of a nail.
The Mentos® tablets were glued to the underside of the holed caps on GAK Day,
but we can’t guarantee that they’ll still be secured when ready for use. Check to
see if the Mentos® tablets are indeed still secured. If they aren’t, use a tiny bit of
Elmer’s glue to re-attach the tablets to the underside of the caps: we recommend
three tiny dots of glue on underside of the cap at 0°, 120° and 240° around the
periphery of the hole.
National Chemistry Week 2014 - Cleveland Section
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Introduction and Checklists
Presenter’s Guide
Activities To Do When You Get To The Library
NOTE: Arrive at least 1 hour before show time to allow for introductions and
set-up depending on how quickly you think you can perform the steps listed in the
Experimental Set-up section. DO NOT assume that a librarian will be present to
help you set up for the experiments.
Introduce yourself to the Head Children’s Librarian.
Confirm that the tables and chairs are set up properly.
Confirm that all tables are covered in newspaper or have chemical/liquid resistant
surfaces.
Obtain those supplies from the list on page 9 if provided by library.
Optional: Ask the Head Children’s Librarian or an assistant to take pictures WHEN
ABSOLUTELY EVERYONE IS WEARING GOGGLES during the
demonstration (subject to parents/guardians having given permission to take the
pictures).
Complete Experimental Set-Up; see page 13.
Completed?
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Set-up note! If you follow the script as originally written, there are many cups and
other items on the tables. Depending on the size of your tables, and the activity
level of your students, you may choose to distribute fewer items originally. If so,
then perhaps keep the remaining experiments’ material at your presenter’s table—
on the plastic tray by an assistant if you have one—and distribute these items
throughout the program.
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Set up an ‘Entrance’ area table to allow space for goggle distribution and fitting by
the parents, photo permission form signing, and (at the end of the program)
distribution of literature. Place copies of the ACS Celebrating Chemistry, the ACS
Photo Permission forms and any other literature on this table.

You may wish to set up an ‘Exit’ area table to allow space for end-of-program
activities: goggle return and literature distribution.
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Activities To Do At the Start of The Demonstration
Timing
Ask the parent/guardian for permission to photograph the children for possible use
on our website and obtain their signatures to this effect. If that permission is not
obtained, make sure that that student is positioned in such a way in the room that
they won’t be included in the photographs, or do not take any photographs. It is
advisable to seat students with photo permission at the same table.

Hand out goggles and help adjust to the correct fit (if necessary). Tell the student
to pull the air vents to the open position. Everyone must wear goggles at all times.
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National Chemistry Week 2014 - Cleveland Section
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Introduction and Checklists
Presenter’s Guide
Activities To Do During The Demonstration
Activity/Experiment
Timing
Type
Time (mins)
2
Welcome & Introduction
Group
5
Exp. 2: Why are Some Candies Sour?
Individual
5
Exp. 3: Making Gummy Worms
Individual
10
Exp. 4: The Many Colors of Candy
Individual
10
Exp. 5: M&M® Wheel & Floating M’s
Individual
3
Exp. 6: Pop Rocks Rock
Individual
5
Group Demo
15
Exp. 1: Sugared and Sugar-Free Candy
Exp. 7: A Candy Fountain
Closing Comments
2
Collect goggles, hand out literature & thank everyone
for coming.
2
Ask students to complete their Student Feedback forms
---
2
Total Time
~60
Activities To Do Immediately After The Demonstration
Clean up as indicated in the Clean Up & Return section (p. 41).
Give the mailing envelopes (the Photo Permission, Student Feedback and
Demonstrator Feedback forms) along with the box of student and adult goggles to
the librarian for return to Julia Boxler via interlibrary mail. (Those outside of the
CCPL network can return items to your nearest CCPL branch for return to Julia
Boxler-YTH. See www.cuyahogalibrary.org for branch listings.) Please return all
materials within two weeks of NCW.
Give any leftover literature to the librarian (CCPL library kits only).
Activities To Do Once You Get Home
Email photos to Bob Fowler at [email protected] along with some text describing
each.
Smile! You have just shared your joy of science and chemistry with children,
possibly inspiring them to become great scientists, chemists, biologists, engineers...
National Chemistry Week 2014 - Cleveland Section
Completed?
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Completed?
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Supplies for Demonstrator to Bring from Home
Presenter’s Guide
Supplies for Demonstrator to Bring from Home
Items for Presenter to Provide (or to request in advance from the librarian—do
not assume that the library will have these materials)
1.
2.
3.
4.
5.
6.
A 4 cup Pyrex glass measuring cup or equivalent to heat water in
1 insulating cloth hot pad with which to hold the hot Pyrex cup.
A teaspoon measure
A tablespoon measure
A ¼ teaspoon measure
1 2-gallon plastic jug filled with tap water. Note: at least 2 gallons of water will be
required between Exps. 3, 4 & 6. If your library/facility doesn’t have easy access to a
way to fill this jug with water, bring your own.
7. 1 large garbage bag for solid waste collection.
8. 1 bucket for liquid waste collection (optional if a sink is available within the demo room).
9. Pens for parents to fill out photo permission forms.
10. 1 roll of paper towels
11. Some extra newspapers to put under the tray in Experiment 7 and on the tables if the
library hasn’t covered them for you.
12. A roll of masking tape to hold the newspapers flat on the tables.
13. A hammer & a cutting board in case you haven’t crushed the hard candy at home (see
page 5).
Optional: IF you care to take pictures, bring a digital camera for doing so. Make sure students’
parents have given their permission for the children to be photographed on the ACS form and
that the students and any adults to be photographed are ALL wearing goggles. You might want
to assign the photography chores to an assistant during the demonstration. It is better to have
close ups of one or a few students to show what they are doing and their excitement. Please
send Bob Fowler copies of you pictures at [email protected] along with some text describing
each.
Note: If you will be performing multiple demonstrations on the same day with the same
goggles, you’ll need to sanitize them between demonstrations (refer to p. 41 for more
information). For this you’ll need:
1. small quantity of household bleach
2. wash bin or bucket
3. old towels or cotton paper towels for drying (soft so as not to scratch the
goggles)…OR…individual sanitizer wipes (soft so as not to scratch the goggles).
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Supplies Included in Your Kit
Presenter’s Guide
Supplies Included in Your Kit
General
1. Materials for 7 Experiments—all in numbered plastic bags.
2. 1 copy of this script.
3. 1 9x12 manila envelope addressed to Julia Boxler – YTH containing 25 copies of the ACS
Photo Permission and Student Feedback forms and 1 copy of the Demonstrator Feedback
form
4. 25 copies of Celebrating Chemistry for distribution.
5. 25 copies of the Candy Sense—ation handout listing website with experiments to do at
home and a booklist.
6. 1 plastic tray to be used for distributing materials (if you wish) and for liquid
containment for Exp. 7. (May be external to the kit box if it’s too large.)
Also included (external to the kit box):
7. 1 box of goggles (25 student & 2 adult sizes, addressed for return to Julia Boxler - YTH)
Materials by Experiment:
Experiment 1: Sugared and Sugar-Free Candy (Group Experiment)
1. 2 pieces each of 2 hard candy samples in their original wrappers. Two are sugarsweetened (in a baggie marked “S” for sweetened) and two are artificially-sweetened (in
a baggie marked “SF” for sugar free)).
2. 1 small thermometer
3. 10 10-ml vials marked “B” each containing 7-ml of Benedict’s solution.
4. 3 9-oz. clear plastic cups
5. 10 small medicine cups
6. 10 wooden stirrers
7. 1 baggie containing 31 g sugar.
Experiment 2: Why are Some Candies Sour? (Individual Experiment)
1. 25 2-oz. plastic cups labeled as follows:
a. 5 as “ST” (for Sweet Tarts®)
b. 5 as “WH” (for Warheads®)
c. 5 as “MM” (for M&M’s®)
d. 5 as “SH” (for Shockers®)
e. 5 as “LS” (for Life Savers®)
2. 25 pieces of candy:
a. 5 Sweet Tarts®
b. 5 Warheads®
c. 5 M&M’s®
National Chemistry Week 2014 - Cleveland Section
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Supplies Included in Your Kit
Presenter’s Guide
3.
4.
5.
6.
7.
8.
d. 5 Shockers®
e. 5 Life Savers®
5 9-oz. cups marked “W”
25 wooden stirrers
25 plastic spoons
25 Q-Tips
25 strips of pH paper
5 pH color scales
Experiment 3: Making Gummy Worms (Individual Experiment)
1.
2.
3.
4.
5.
6.
7.
25 4-oz. plastic cups marked “A” (for activator [CaCl2])
1 baggie marked “C” containing 10 tsps of CaCl2.
1 pop bottle marked “W” (for “worm goo”) containing about 140 ml of alginate solution 1
25 4-oz. plastic cups marked “W” (for “worm goo”)
25 plastic forks.
26 jumbo beral pipettes
25 paper towels
Experiment 4: The Many Colors of Candy (Individual Experiment)
1. 26 9-oz. plastic cups marked “S” (for salt solution)
2. 1 baggie containing 25 “black gem” candies
3. 1 pop bottle marked “S” filled with about 250 ml of 1% salt solution
4. 25 4” X 4” pieces of waxed paper
5. 25 toothpicks
6. 26 small strips of filter paper ¾” wide
7. 25 1-ml beral pipettes
8. 25 paper towels
9. 26 golf pencils
10. 26 wooden stirrers.
Experiment 5: M&M Wheel & Floating M’s (Individual Experiment)
1.
2.
3.
4.
5.
6.
1
25 Petri dishes and covers.
100 M&M’s® of different colors.
25 paper towels.
25 small medicine cups marked “M” (for M&M’s®).
25 pieces of plain white paper, 4” X 4”.
1 unlabeled plastic sandwich-sized bag
There are two pop bottles in the kit: the alginate solution in the bottle marked “ W” is cloudy;
the salt solution in the bottle marked “ S” is clear.
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National Chemistry Week 2014 - Cleveland Section
Supplies Included in Your Kit
Presenter’s Guide
Experiment 6: Pop Rocks® Rock (Individual Experiment)
1. 50 2-oz. cups:
• 25 marked “P” (for Pop Rocks®)
• 25 marked “W” (for water).
2. 14 packages (0.24-oz. each) of Pop Rocks® hard candy.
3. 25 4” X 4” pieces of waxed paper.
Experiment 7: A Candy Fountain (Group Demonstration)
1.
2.
3.
4.
2 small bottles of diet 7-Up.
2 bottle caps with 7/16’ holes with a Mentos® tablet attached underneath the hole.
A nail.
A plastic tray.
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Experimental Setup
Presenter’s Guide
Experimental Setup
Note: In the following the term “station” refers to each of the 5 places at all 5 student tables
(i.e., 25 places total). We are not putting these materials at the demonstrator’s table this year.
Experiment 1: Sugared and Sugar-Free Candy (Group Experiment)
•
At center of each table place the following:
1.
2.
3.
4.
•
2 10-ml vials marked “B” containing 7 ml of Benedict’s solution.
2 small medicine cups, one marked “S” and other marked “SF”
2 wooden stirrers.
Put ¼ teaspoon of crushed candy with sugar (from the baggie marked “S”) into the
medicine cup marked “S”, and ¼ teaspoon of crushed sugar-free candy(from the baggie
marked “SF”) in the other medicine cup marked “SF”.
At the demonstrator’s table place the following
1. The baggie containing 31 g sugar.
2. Place three 9-oz. clear plastic cups at the Demonstrator’s table in full view of the
students. After using your 4-cup Pyrex measuring cup (or equivalent) to distribute water
to the other experiments, fill it with about 18-20 oz. (2.5 cups or 0.6L) of warm water.
Keep the thermometer with the Pyrex measuring cup. Note: Just before the program
begins an assistant will need to heat this water to about 170°F using the facility’s
microwave. This will require microwaving the water for about 30 or 45 secs. Make sure
the metal thermometer isn’t in the Pyrex cup as the water is being microwaved.
Experiment 2: Why are Some Candies Sour? (Individual Experiment)
•
At center of each table place the following:
1. 1 pH color scale
2. 5 2-oz. plastic cups labeled as follows:
a. “ST”
b. “WH”
c. “MM”
d. “SH”
e. “LS”
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Experimental Setup
Presenter’s Guide
3. Removing the wrappers (if any), put the following candies into the indicated cups:
a. 1 Sweet Tart® into the cup marked “ST”
b. 1 Warhead® into the cup marked “WH”
c. 1 M&M® into the cup marked “MM”
d. 1 Shocker® into the cup marked “SH”
e. 1 Life Saver® into the cup marked “LS”
4. one 9-oz. cup marked “W” filled about ¾ full of tap water
•
At each station place the following:
1.
2.
3.
4.
1 wooden stirrer
1 plastic spoon
1 Q-Tip
1 strip of pH paper
Experiment 3: Making Gummy Worms (Individual Experiment)
•
At each station place the following:
1. 1 4-oz. plastic cups marked “A” (for Activator/CaCl2). Fill each cup about ¾ full with
the CaCl2 solution from the plastic jug.
2. 1 4-oz. plastic cups marked “W” (for Worm Goo--alginate). Distribute the alginate
solution from the pop bottle marked “W” equally into these cups (approx. 5 ml per cup).
You can use the jumbo pipette for this purpose, but don’t put too much more than 5 ml
into each cup—you only have 140 ml total alginate liquid.
3. 1 jumbo beral pipette.
4. 1 plastic fork.
5. 1 paper towel.
Experiment 4: The Many Colors of Candy (Individual Experiment)
•
At each station place the following:
1. 1 9-oz. plastic cup marked “S”.
2. Into each 9-oz. cup put about 5ml (~1 teaspoon) of 1% salt solution from the pop bottle
marked “S” containing about 150 ml of the solution. You want just enough salt solution
in each cup to cover the bottom.
3. 1 “black gem” candy
4. 1 4” X 4” piece of waxed paper
5. 1 toothpick
6. 1 small strip of filter paper ¾” wide
7. 1 1-ml beral pipette
8. 1 paper towel
9. 1 golf pencil
10. 1 wooden stirrer.
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Experimental Setup
Presenter’s Guide
•
At the demonstrator’s table place the following:
1.
2.
3.
4.
1 9-oz. plastic cup marked “S”. Do NOT put the salt solution in this cup.
1 small strip of filter paper ¾” wide
1 wooden stirrer
1 golf pencil
Experiment 5: M&M® Wheel & Floating M’s (Individual Experiment)
•
At each station place the following:
1.
2.
3.
4.
5.
A small medicine cup marked “M” each containing 4 different colored M&M’s®.
A white piece of paper 4” X 4”.
1 paper towel.
Place the Petri dish in the center of the white piece of paper.
Carefully fill each Petri dish to within 1/8” of the rim with tap water and cover.
Experiment 6: Pop Rocks® Rock (Individual Experiment)
•
At each station place the following:
1. One 2-oz. cup marked “P”. Put about 1 teaspoonful of Pop Rocks® candy into this cup.
You have 14 0.24-oz. packages of Pop Rocks® , each containing about 2 teaspoonsful, to
use.
2. 1 4” X 4” piece of waxed paper. Note that the Pop Rocks® appear to be rather
hygroscopic, so place the small piece of waxed paper over each cup marked “P”..
3. One 2-oz. cup marked “W” approximately half full with tap water.
Experiment 7: A Candy Fountain (Group Demonstration)
•
At the demonstrator’s table place the following:
1. 2 small bottles of carbonated diet pop
2. 2 pop caps with 7/16” holes drilled in them. A Mentos® candy is glued to the underside
of each cap.
•
Somewhere where there’s an open space 2, place the following:
3. A plastic tray. Put newspaper under the tray.
Note: Put a Student Feedback Form and a copy of this year’s color, two-sided Handout at each
station.
2
If it’ s a nice day, you might want to consider going outside for this one. If you do, bring
your tray with you at the time of the experiment.
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Experimental Setup
Presenter’s Guide
Greet the Students (and Parents) Upon Their Arrival, Distribute
Goggles, and Organize the Seating
1. If you plan to take pictures, ask the parents/guardians to give or withhold their permission for
the student to be photographed via the ACS consent form. Don’t forget to obtain their
signatures on the forms provided.
Note: You might want some librarian assistance with this: IF you plan to take photos
and some of the parents have denied permission, you’ll want to put all of the children
who aren’t going to be photographed at a separate table. The librarian may have separate
but similar forms for the library’s use. Make sure to get the enclosed forms signed—do
not rely on the library’s forms.
2. Help the students or have the students’ parents put on their goggles. Adjust the straps as
necessary. (Note: These goggles are sanitized each year and prior to each demonstration.)
Suggest that the students pull the air vents open for comfort while wearing the goggles.
3. Distribute the students 3-5 per table. 5 students per table would be best.
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The Program
Presenter’s Guide
Opening Discussion
Introduce the Items on the Tables:
•
•
•
Tell the students not to touch anything until told to do so and not to shake the table or things
could fall over and the fun ruined. Willie Wonka (in the book Charlie and the Chocolate
Factory) has 2 rules for his Inventing Room. One is “Enjoy yourselves, but just don’t touch
anything!” This is especially true this year since there’s a round dish at each person’s
place that nearly full of water! Never taste or smell anything, as if they were in a
laboratory!
Tell the students that various items have been gathered for them on their table. Most items in
today’s program are common household items.
Put on a pair of the adult-sized goggles. If you have an assistant, ask them to do the same.
Verify that all students have goggles on—this goes double for the CO2 Fountain
experiment!!
Introduce Yourself and the Program
•
•
•
•
•
Introduce yourself as a chemist or science teacher/engineer (or state your interest in
chemistry), and introduce the American Chemical Society as the largest organization in the
world devoted to a single profession.
Introduce National Chemistry Week—what it is and why we do it. (Hint: it is a nationwide
event put on by volunteers like you to let non-scientists know about chemistry, how much fun
it can be and how it can improve our everyday lives.)
Tell the students that today’s Program is all about candy, but we’re not allowed to let them
eat anything we’re using or making today. The students can buy all of the candies that we’re
featuring today at their local drugstore under their parents’/guardians’ supervision.
Please tell the students that we’d really like for them to vote for the experiment they liked
most in today’s Program. At the end of the Program they’re going to have a chance to vote
on their favorite experiment as well as the one that they think taught them the most. They’ll
do this via the hardcopy Student Feedback form at their places. So tell them to remember
what they like about each experiment.
Also tell them that they have a Student Handout at their place which we’ll use as we go
through the Program. Tell them to make sure they take it home because it has interesting
info, a list of books to read, and links to do some of today's experiments at home.
Now let’s have some fun!
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The Program
Presenter’s Guide
Background for the Demonstrator (only)
In most cases this year there’s only 25 of everything. We’ve found that putting a 26th copy of
every item on the Demonstrator’s table is somewhat wasteful since the Demonstrator often
doesn’t have time to use the 26th item on his/her table, even for demo purposes. The exception
this year is Experiment 4. In this case we deem it sufficiently important that the Demonstrator
show the students how to fold, mark and place their filter papers that we’ve included one set of
the appropriate items on the Demonstrator’s table. The only other items on the Demonstrator’s
table this year are those to be used for the first and last experiments.
Note also that most text in the experimental writeup in Italics is a note for your eyes only.
Some introductory logistics for the students:
Please remind the students that it’s especially important not to rock or hit the tables this year
because there is a round dish almost full of water at everyone’s place. This goes doubly so
during Experiment 5 when we use this Petri dish.
No tasting or eating anything.
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The Program
Presenter’s Guide
INTRODUCTION FOR THE STUDENTS
Story Line:
The National Chemistry Week Theme this year is The Sweet side of Chemistry and it’s all about
Candy!
Have you read the book Charlie and the Chocolate Factory or seen the movie? Remember
Charlie and the kids go on a tour of Willy Wonka's Chocolate Factory?!!....where everything in
the Chocolate Room is edible!! Where new and delicious sweets are being invented in the
Inventing Room.
Just like Willy Wonka made wonderful inventions, chemists and food scientists are in their
'inventing rooms' called 'labs' making wonderful concoctions. We’re going to go on a virtual
(pretend) “tour” today and we’ll call our factory “The Candy Sense-ation Lab”. Look at your
handout and you’ll see a path like a game. Starting at the top, we will move down, and visit
some places where kids and chemists are enjoying the sense-ations of candy.
Chemists and chemical principles certainly make candy more appealing to the senses....we make
the experience much more....flavorful and colorful.
We aren’t going to actually eat candy here today. Remember Willie Wonka has a rule for his
Inventing Room: “Enjoy yourselves, but just don’t touch anything!” Remember chemists do not
eat anything in their labs.
All our experiments will involve the physical properties of candy, which we can determine using
our senses. Chemists, when they are studying anything, use their senses first of all.
But deeper than just the outward physical properties of candy, chemistry is behind the scenes!
********
From here go to: Introduce the Experiment (#1) and then to Tell the students in order to
continue the story line.
Experiment Purpose and General Methodology is a summary for the demonstrator not meant to
be read to the students.
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The Program--Experiment 1: Sugared and Sugar-Free Candy
Presenter’s Guide
Experiment 1: Sugared and Sugar-Free Candy (Group
Experiment)
Experiment Purpose & General Methodology
For the demonstrator: The sweeteners in candy can be broadly classified as either natural or
artificial (man-made by chemists and food scientists). Chemists use a reagent called Benedict’s
solution to determine the presence of natural reducing sugars (including all monosaccharides
and many disaccharides); their presence is indicated by a cool color change. Two types of
candy, one with natural fructose and one sugar-free, will be tested.
Introduce the Experiment (TASTE)
Tell the students:
Ask: What are our 5 senses?
ears/hearing/sound)
(1-taste, 2-nose/smell, 3-touch/feel, 4-eyes/sight, 5-
Ask 1 or 2 students: “What’s your favorite candy? Why do you like it? The taste? The color?
The shape?]
Look at your handout. At the start, do you see someone eating chocolate? We’ll start our Candy
Sense-ation Tour with TASTE. Ask: What makes candy taste so good? (sugar, chocolate,
flavors like fruit, mint, cinnamon….)
Our experiment at this TASTING spot has to do with the thing that gives candy its BIG appeal:
SWEETENERS. Sweeteners can be either natural like sugar or artificial (man-made by chemists
and food scientists to help people who don’t want to eat too much sugar). (By the way, it is
important that we don’t eat too much candy because there’s lots of Calories in it!)
We’re going to test 2 kinds of candies now to see which kind has sugar and which is sugar-free
(which means it has an artificial sweetener). Using our sense of TASTE we can certainly tell
that these candies are sweet, but we can’t tell which has natural sugar and which doesn’t. We
have to turn to chemistry! We will use a chemical called Benedict’s Solution and look for a
color change which happens when natural sugar is present.
The 2 kinds of candies have been crushed so they will at least partially dissolve in the Benedict’s
Solution. We will then heat the solution in a ‘heating bath’ to make the chemical reaction go
faster. You’ll start the experiment at your tables, but then, because the water in the heating bath
is so hot, I (the demonstrator) will help you complete the experiment at the head table.
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The Program--Experiment 1: Sugared and Sugar-Free Candy
Presenter’s Guide
Performance Details
Tell the students to do the following:
1. [Just before the program begins (or, if you have an assistant, while you’re giving the
introduction), use the library’s microwave to heat the water in the 4 cup Pyrex measuring
cup or equivalent to about 170°F. If you start with hot tap water, the starting
temperature will be about 115 °F, so this heating process should take about 30 seconds
to 1 minute. Use the enclosed small thermometer to approximate 170°F. DO NOT heat
to boiling, and DO NOT PUT THE METAL THERMOMETER INTO THE
MICROWAVE! It’s recommended that person handling the heating cup use insulating
cloth hot pad to do so. When heated, distribute the hot water between the 3 9-oz. cups on
your Demonstrator’s table. The purpose of the three cups is to provide a hot bath to
speed up the reaction.]
2. At the center of each table there are 2 10-ml vials marked “B”, 2 small medicine cups
containing some crushed candy and two wooden stirrers. Ask two students to pick up
one 10-ml vial each and two additional students to each pick up a wooden stirrer and a
medicine cup with crushed candy in it. Ask the first two students to remove the sealing
material and then remove the lids from their vials taking care not to spill the liquid. Ask
each student with the stirrers to get as much as possible of the crushed candy from his/her
cups onto the end of their stirrers and carefully place these particles into one of the two
vials. (The samples should be put in different vials and NOT mixed together.) Ask the
students with the vials to put the caps back on and screw them tightly until they hear a
“click”.
3. Ask the last student at each table to shake these two vials for a minute or so [time it!] to
dissolve some of the hard candies. After shaking them, this student should take the vials
up to the Demonstrator’s table where he/she (i.e., the Demonstrator) will put them intact
into any of the three cups of hot water. (We’d prefer that the students not be exposed to
the very hot water.)
4. While this experiment is “cooking”, let’s go to the next one. [It shouldn’t take more than
5-10 minutes for the Benedict’s to change from clear blue to green to brown to a brick
red in the presence of sugar.]
Conclusions
Tell the students:
What happened? [The color should have changed from blue to green to brown to brick red upon
completion of the reaction in half of the samples—those receiving sugar-sweetened candy.
There should have been no color change in the vials receiving sugar-free candy. Color changes
indicate the presence of reducing sugars such as the fructose added to many sweetened candies.
No color change indicates that the candy was sugar free.] Notice that none of the vials are
labeled, so at first we don’t really know whether they received candy with or without sugar. If
there was sugar present in the candy, the solution should have turned from light blue to brick red.
So if there was no color change in a particular vial, that means that the candy was sugar free.
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The Program--Experiment 1: Sugared and Sugar-Free Candy
Presenter’s Guide
Now that we know how to detect whether candy is sweetened by sugar, do you know what effect
the sugar in candy has on your body? Ans: Too much sugar of any type in your diet can lead to
dental cavities, weight gain and overall poor nutrition, especially if the sugary foods are taking
the place of foods containing nutrients and vitamins. Candy on a regular basis may cause you to
eat too many Calories overall, which leads to weight gain. The American Heart Association says
that women and men should consume no more than 100 to 150 Calories per day from sugar,
respectively.
A single serving of peanut chocolate candies, for example, can provide your body’s entire
maximum recommended Calories from sugar all at once, and a single serving of M&M’s®
contains 31 g of sugar [hold up baggie from the Demonstrator’s table]. That’s a lot of sugar in a
handful of M&M’s®—and a lot of Calories!
Technical Information (for the Demonstrator):
Benedict's test is commonly used for the presence of reducing sugar(s); however, other reducing
substances also give a positive reaction. This includes all monosaccharides and many
disaccharides, including lactose and maltose. Even more generally, Benedict's test will detect
the presence of aldehydes, and alpha-hydroxy-ketones, including those that occur in certain
ketoses. Thus, although the ketose fructose is not strictly a reducing sugar, it is an alphahydroxy-ketone, and gives a positive test because it is converted to the aldoses glucose and
mannose by the base in the reagent.
Simple sugars are called monosaccharides and include glucose (also known as dextrose),
fructose and galactose. The table or granulated sugar most customarily used as food is sucrose, a
disaccharide. (In the body, sucrose hydrolyzes into fructose and glucose.) Other disaccharides
include maltose and lactose.
One use of Benedict’s test is the determination of glucose levels in people suffering from
diabetes.
A positive test with Benedict's reagent is shown by a color change from clear blue to a brick-red
precipitate. The principle of Benedict's test is that when reducing sugars are heated in the
presence of an alkali, they’re converted to powerful reducing compounds known as enediols.
Enediols reduce the cupric ions (Cu++) present in the Benedict's reagent to cuprous ions (Cu+)
which are precipitated as insoluble red copper(I) oxide. The color of the obtained precipitate
gives an idea about the quantity of sugar present in the solution, hence the test is semiquantitative. A greenish precipitate indicates about 0.5% concentration; yellow precipitate
indicates 1% concentration; orange indicates 1.5% and red indicates 2% or higher concentration.
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The Program--Experiment 1: Sugared and Sugar-Free Candy
Presenter’s Guide
Examples of the Calories found in candy are as follows 3:
Candy
1. Peanut Chocolate
Candies
2. Smarties
3. SweetTarts
4. Jelly Beans
5. M&M’s®
3
4
Cal/gm 4
Cal/serving
Serving
Size (g)
Sugar
(g)
Sugar
%
5.1
250
49
25
51
3.6
4.0
3.6
4.8
25
60
110
230
7
15
31
48
6.3
12
21
31
90
80
68
64
http://caloriecount.about.com/
When spelled with a capital C, “ Calories” refers to kcal or a food calorie.
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The Program--Experiment 2: Why are Some Candies Sour?
Presenter’s Guide
Experiment 2: Why are Some Candies Sour? (Individual
Experiment)
Experiment Purpose & General Methodology
For the demonstrator: Chemists, food scientists and candy manufacturers can enhance the taste
and flavor of candy using things like esters and citric acid. Citric acid is a naturally occurring
acid that’s found in all citrus fruits, and it makes some of them sour. We will test a range of
candies for their ‘sour’ness using pH paper, which chemists use as a scale to rate the acidity
(sourness) and basicity (bitterness) of materials. Because we are not allowed to taste candies
today, we will use chemistry to determine how much, if any, sourness is present.
Introduce the Experiment (TASTE, cont.)
Tell the students the following:
Look at your handout. Next to the character enjoying the sweetness of chocolate is someone
eating a puckery lemon. Do you say, “Yum! I like that lemon taste.” Or “Ugh! That’s awful!”
??
We are going to continue our exploration of the sense of TASTE by doing an experiment with
some sour candies.
Remember in the lab we can’t taste candies to tell if they are sour or sweet, but we can do what
chemists do…..and that is to use pH paper which changes different colors depending on how
sour something is. This paper is also used to measure bitterness (but I don’t know of any candy
that is bitter; usually bitter or soapy tasting things are not good for us to eat).
You are each going to have a candy that may be sweet, or it may be just a little sour, or it may be
a lot sour.
You will dissolve some of your candy in water and touch it to the pH paper. You will see if the
paper changes color and compare it to a scale of colors. This test that chemists use will measure
the level of a chemical added to candies to make them sour. This chemical is citric acid which is
found in citrus fruits.
Performance Details:
In the center of the table are 5 plastic cups labeled “ST”, “WH”, “MM”, “SH” and “LS”
containing, respectively, a Sweet Tart®, a Warhead®, an M&M®, a Shocker® and a Life
Saver®. Each student should take one of these cups and one of the plastic spoons there. They
should also take a strip of pH paper. There is a plastic cup marked “W” containing tap water for
everyone’s use. The students should pass the cup of water around, and each should take two
teaspoons of water and put it into their own small cup with the candy. Now they should take the
stirrer in front of them and dissolve the candy somewhat by stirring for a minute or two.
24
National Chemistry Week 2014 - Cleveland Section
The Program--Experiment 2: Why are Some Candies Sour?
Presenter’s Guide
Once the candies have dissolved somewhat each student should take the Q-Tip in front of them,
dip the end of it into the liquid in their cup, and then touch the wet end of the Q-Tip to one end of
their strip of pH paper. The students should now pass around the pH scale from the center of
table. Each in turn should compare the color on the wet end of the pH paper to the pH color
scale. The number on the scale is the acid level (pH) of the candy. Each of the numbers should
be between about 2 and 6.
Have the students remember their pH number.
Conclusions
Ask/Tell the students the following:
Which candy had the lowest pH (i.e., the lowest number on the color scale)? [Ask for input.]
Ask the students to compare the pH paper to the standard and use the colors to rank the candies
from lowest pH to the highest. If we were allowed to taste these candies, which one do you think
would be the sourest? The one(s) with the lowest pH (i.e., with the most acid) should taste the
sourest. If you’ve eaten these candies before, does the conclusions the group reached agree with
what you remember about these candies? Once again we can use chemistry instead of our
mouths to find out how sour something might be. If we didn’t know what the material was,
using chemistry is certainly safer than possibly eating something that could be harmful to us.
Demonstrator: At this point return to the Conclusions section of Experiment 1. The reaction
takes about 5 minutes to complete, so it should be complete by now.
Technical Information (for the Demonstrator):
The sourness of many candies is imparted by the addition of citric acid.
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The Program--Experiment 3: Making Gummy Worms
Presenter’s Guide
Experiment 3: Making Gummy Worms (Individual Experiment)
Experiment Purpose & General Methodology
For the demonstrator: Candy can appeal to our sense of TOUCH. Candy can have a variety of
TEXTURES that we can feel with our hands or mouth. One candy with a familiar “feel” for kids
of all ages is gummy worms. In this experiment we will demonstrate the chemistry behind this
popular candy. Instead of using sugar and gelatin, as in the original, because of time
constraints, we will make a synthetic lab version using alginate polymer cross-linked via an
activator (a solution of calcium chloride) that the students can feel, but not eat.
Introduce the Experiment (TOUCH/FEEL)
Tell the students the following:
If you look at your handout you’ll see that we’ve ignored the sense of smell. But it is an
important sense! Chemists and food scientists do a lot to enhance the smell of candies. They’ve
created chemicals like esters which have the fragrance of things like pineapples and bananas.
The sense of smell helps out your sense of taste. If you didn’t have your nose, an apple might
taste like a potato. They have the same TEXTURE.
Look at your handout again. The next stop on our candy lab tour invites us to investigate
TEXTURE….to TOUCH or FEEL. We use our hands or mouth to feel candy. But today, since
we can’t use our mouths, we will make some ‘artificial’ candy and feel its texture using just our
hands.
Ask: What are some of the TEXTURES of candy? (here’s a fun litany: soft, hard, bumpy,
smooth, rubbery, gooey, sticky, stretchy, gummy, gritty, sandy, creamy, crunchy, light, heavy,
melty, solid, hollow, spongy, frothy, fizzy…)
Ask: Have you ever eaten candy that is gummy or gooey? (gummy worms or gummy bears) Did
you ever wonder how gummy worms are made? Wouldn’t it be fun to make our own?? And get
to touch them? (We can’t eat them today).
The first gummy worms were made long ago and far away (in Germany in 1922) using gelatin
(like in Jell-O®) and sugar. Since we don’t have time for gelatin to set today, we’re going to use
chemistry to create a faster-forming ‘gummy worm’. And we will get to TOUCH them, but not
eat them.
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The Program--Experiment 3: Making Gummy Worms
Presenter’s Guide
Performance Details
Tell the students the following:
In this experiment we’re going to investigate the wonderful world of polymers. Polymers are
chains of atoms linked together by chemical bonds. Sometimes the long chains are linked
together by smaller chains so that the long chains are more rigid and the final polymer is not
liquid-y but firmer.
To show this on a big scale, all the students need to get up and move to an open space in the
room. Ask the students to form three lines of approximately equal length with the first two lines
facing the third. Ask the two outer lines of students only (i.e., lines 1 and 3) to lock arms and, on
the count of 3, take two steps to their left all together while the middle line observes. No
problem for each outer line to move to their left—right?
Now ask the students to return to their original positions (i.e., take two steps back to their right).
Ask the students in the middle line to turn 90° (doesn’t matter which direction) and join hands
with one student in each of the outer lines while the outer line students keep their arms locked.
Now ask each of the two outer lines (only) to again take two steps to their left without letting go
of the students in the middle. Not so easy to do this time, is it? The middle line keeps the outer
lines from being able to move freely to their left or right. It’s as if all the students now formed
one large unit which was no longer free to move right and left. Ask the students to return to their
seats.
What you’ve just experienced is an illustration/example of what chemists call crosslinking. Each
of you represented an atom—a link in the chemical chain, if you will. The two outer lines of
students with arms locked represent atoms joined together by what chemists call chemical bonds.
At first the two outer lines were able to move to their left (and right) freely. Then the lines were
connected together by bonds with the middle line. Chemists call this process of linking two
chemical chains together similar to the way we linked the two outer lines of students together
crosslinking. Crosslinking prevents the two outer chains from moving freely anymore.
Let’s see how this works in chemistry by making our own gummy worms. In front of each
student is a plastic cup marked “A” containing an activator, another cup marked “W” containing
worm goo, a pipette and a plastic fork. Take your pipette and fill it with worm goo from the cup
marked “W” (it works like an eye dropper). Now carefully squirt the worm goo into the cup
marked “A”.
What’s happening? Ans: In very short order the crosslinked polymer forms. The students can
fish their gummy worms out of the CaCl2 solution (cup marked “A”) with their forks. If they’ll
place these gummy worms on their paper towel, they can play with them. Then they will need to
set them aside since they can’t take them home, and they shouldn’t eat them at any time.
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The Program--Experiment 3: Making Gummy Worms
Presenter’s Guide
Conclusions
Tell the students the following:
The worm goo is made up chemically of freely moving chains of atoms like the two outer lines
of students before crosslinked by the middle line. The activator is equivalent chemically to the
middle line of students. It contains calcium ions, and when it’s added to the worm goo, the
chemical chains are crosslinked by the calcium ions. One feature of crosslinking is that the
molecular chains begin to act as one huge unit and begin to get gummy. Gummy worm are made
by a very similar process.
Technical Information (for the Demonstrator):
The gummy worms candy that we eat was first made in Germany in 1922 and is made of gelatin,
corn syrup, sugar (21g per serving!—as much as Jelly Beans), citric acid, and lactic acid.
Synthetic gummy worms is a great way to introduce students to the chemistry behind polymers.
Worm Goo is a long chain of molecules called a polymer. When the Worm Goo comes in contact
with the Activator, the goo immediately changes from a liquid to a solid! That’s because the
Activator acts a cross-linking solution that links the long strands of polymers in the goo together.
Alginate is a type of polysaccharide that occurs naturally in all brown algae as a skeletal
component of their cell walls. Alginate is used in food because it is a powerful thickening,
stabilizing, and gel-forming agent. Some foods that may include alginate are ice cream, fruitfilled snacks, salad dressings, pudding, onion rings, and even the pimento strips that are stuffed
into green olives. Most alginate used in foods is in the form of sodium alginate. In order to form
a gel, sodium alginate needs to come into contact with divalent ions such as calcium (Ca++). As
soon as sodium alginate (Figure 1) is added to a solution of calcium chloride, a gel forms as the
sodium ions (Na+) are exchanged with calcium ions (Ca++) and the polymers become crosslinked
(Figure 2). The calcium ions are able to crosslink the alginate polymers because they can form
two bonds, as opposed to monovalent ions such as sodium, which can only form one bond. The
longer the alginate is in contact with the calcium chloride solution, the more rigid the gel will
become, as more crosslinks are formed. Also, depending on the concentration of calcium ions,
the gels are either thermoreversible (low concentrations) or not (high concentrations).
National Chemistry Week 2014 - Cleveland Section
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The Program--Experiment 3: Making Gummy Worms
Presenter’s Guide
National Chemistry Week 2014 - Cleveland Section
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The Program--Experiment 4: The Many Colors of Candy
Presenter’s Guide
Experiment 4: The Many Colors of Candy (Individual Experiment)
Experiment Purpose & General Methodology
For the demonstrator: Candies are often appealing because of their colors. The U.S.
government/FDA has certified 7 safe, chemically synthesized colors. These colors make candy
look good and allow people to identify flavors (for example, red color can equate to cherry
flavor). M&M’s® have a colored sugar coating over a chocolate center. This experiment,
which uses ‘black gem’ candies, similar to M&M’s® but with several colors in the coating, will
show that candy colors are often a blend (for example, brown can be a mixture of red and blue
dyes), using the separation technique of chromatography.
Introduce the Experiment (SIGHT/COLOR)
Tell the Students:
Take a look at the handout and see that we are coming to an area of colorful candy: purple, pink,
green, yellow. Candy, with its vivid colors and various shapes can delight our sense of SIGHT.
It is believed that food colorings have been used for over 3,000 years. Natural colors come from
things like beets or grape skins. Chemists have synthesized (made) food coloring that is intense
(bright color), less costly, consistent (same every time it’s made), readily available, and
blendable. The U.S. government has certified 7 of these colors, meaning they are safe to eat.
They include Brilliant Blue, Sunset Yellow, and Allura Red. They can be blended to make
different colors like green and brown.
Ask: What primary paint colors would you use to make green? (blue and yellow)
In this experiment we will use candies called ‘black gems’ that are similar to M&M’s® but with
several colors in the coating. The sugar coating is possibly dyed with a blend of several colors.
We will use a technique chemists call chromatography which will separate the blend of colors
into individual colors.
Performance Details:
Tell the students to do the following:
In front of each student is a 9-oz. plastic cup marked “S”, a small piece of waxed paper, a “black
gem” candy, a golf pencil, a 1-ml beral pipette, a toothpick, a small strip of filter paper, a piece
of waxed paper and a wooden stirrer.
[Demonstrator: use the materials on your table to demonstrate how the filter paper is to be
properly marked, folded and placed on the wooden stirrer over the 9-oz cup as per the following
instructions before allowing the students to do so.]
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The Program--Experiment 4: The Many Colors of Candy
Presenter’s Guide
Each student should take the small piece of filter paper and place their left little finger (reverse if
the student is left-handed) perpendicular across the filter paper at one end so that one side of the
finger is even with the end of the paper (demonstrate how to do this). The student should mark a
line across the paper with the golf pencil using the other side of their finger as a guide--about ½"
from the end.
With the pencil mark at the bottom, stand the piece of filter paper vertically against the outer rim
of the cup (DO NOT put it IN the cup yet) and fold the paper over the lip of the cup. Pick up the
filter paper and fold it once more in the same direction about ¼” from the first fold. When
folded correctly the filter paper will resemble a block letter L with the pencil line near the end of
the L’s vertical arm. We’re going to use the folds to hook the filter paper over the stirrer to hold
the filter paper firmly in place in the center of the cup.
Place the wooden stirrer across the 9-oz. cup marked “S”. Put the small piece of waxed paper on
the table within easy reach, and, using the 1-ml pipette put a single drop of the salt solution from
the 9-oz. cup in the middle of the wax paper. Return the remainder of the solution to the cup.
Carefully position the “black gem” in the center of the drop of liquid and wait for 30 seconds
until the coating on the candy has begun to dissolve. Now rotate the “black gem” to expose a
fresh coating surface to the salt solution and wait an additional 30 seconds. Remove the candy at
that point and place it on the paper towel. The students may also want to use the paper towel to
wipe their fingers.
Lay the filter paper on the table. Use the toothpick to pick up a tiny drop of the colored liquid
and to put a small dot of colored liquid in the center of the line on the filter paper. The dot
should be around the size a pinhead. Pick up the filter paper and blow on it to dry the spot a bit.
Then repeat this procedure a second time starting with putting an additional dab of liquid on the
same spot on the paper with the toothpick. Now hook the strip of filter paper over the wooden
stirrer on the 9-oz. cup so that the end nearest the marked line is just dipping into the solution.
(The bottom of the filter paper must be in contact with the liquid.)
Demonstrator: Proceed to the next experiment while the colors are separating and return here
after the candy fountains in the last experiment to see how the colors have have done their thing.
Conclusions
Tell the students the following:
What happened? Ans.: the strip of paper has several color blotches on it at different levels.
Remember that the sugar coating on the CANDY contained a mixture of several colors. The
process we just used is called Chromatography because it separates out the various colors. The
individual colors traveled up the strip of paper at different speeds and rose to various heights on
the paper. When the process is complete, we can actually see all the colors that went into the
original coating.
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The Program--Experiment 4: The Many Colors of Candy
Presenter’s Guide
Additional Information If Needed: Technical Background 5
Chromatography is a technique for separating a chemical mixture into its components. The
technique is widely used for chemical analysis in scientific research, medical testing, and
industrial processes. Chromatography is based on the fact that different chemicals will pass
through certain types of liquid or solid substances at different rates; moving at different rates, the
individual components become separated from each other. The technique was originated by
Mikhail Tswett, a Russian botanist, in 1906. He named the technique chromatography because in
his experiments he separated the components of plant pigments into bands of color. (Chroma is
the Greek word for "color.")
Many methods for performing chromatography have been developed. The two main types are
gas chromatography, used to separate vaporized mixtures, and liquid chromatography, used to
separate chemical components dissolved in a liquid.
5
http://science.howstuffworks.com/chromatography-info.htm
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The Program: Experiment 5 – M&M Wheel & Floating M’s
Presenter’s Guide
Experiment 5: M&M Wheel & Floating M’s (Individual
Experiment)
Experiment Purpose & General Methodology
For the demonstrator: We are going to continue our investigation into the COLORS of candy.
This time we’re going to see an interesting color effect caused by dissolving colored sugar. The
outer colored sugar coating of M&M’s® placed in water in a Petri dish will dissolve. When you
place 4 in the dish, the colors, if undisturbed, will not mix (an unexpected result, explained by
chemistry). Another surprising result is that the “M” on an M&M® is insoluble and will float to
the top.
Introduce the Experiment (SIGHT/COLORS)
Tell the students the following:
We will continue our investigation of the COLORS of candy because there is a lot to explore.
We know that M&M’s® have a colorful outer sugar shell, which is white sugar that is dyed with
various synthetic dyes, like we learned in the last experiment. Ads used to say that M&M’s®
will melt in your mouth, not in your hand. The chocolate in the middle of the M&M® can soften
at warm room temperature. (Actually chocolate tastes so good because it softens from solid to
liquid-y at the temperature of your mouth and you can get good contact with it on your tongue.)
But the outer coating? Will that “melt in your hand”? What if your hand is wet?
Ask: What do you think will happen if we place different colored M&M’s® in water? (will the
outer sugar shell dissolve?) Ask: If they dissolve, what will the color of the water be? (a
mixture of all the colors? a rainbow of colors?) Let’s try it and see.
Performance Details:
Tell the students to do the following:
It’s very important that you NOT hit or rock the table during this experiment or you might ruin
it! Before you do anything, listen carefully to the instructions.
In front you is a round, covered dish (called a Petri dish) containing water. There are also 4
M&M’s®. VERY CAREFULLY and VERY SLOWLY remove the cover from the Petri dish
and put it next to the dish. When I tell you, I want you to VERY CAREFULLY place one
M&M® at the top, one at the bottom, one at the right, and the last one at the left in the water in
the Petri dish. Make sure that the M’s on the M&M’s® are facing up. Note that each M&M®
should be completely under water when you’re done. If not, dip a finger into the water and
gently touch the top of each M&M® with your wet finger. Try to not disturb the liquid. Now
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The Program: Experiment 5 – M&M Wheel & Floating M’s
Presenter’s Guide
CAREFULLY replace the cover and watch what happens. What do you think is going to
happen? What will the colors do? Will anything else happen?
Demonstrator: Go on to the next experiment so that you allow about 5-10 minutes for the sugar
coatings to dissolve; the colors will begin to spread out. As the 4 color zones begin to intersect,
they won’t mix together. Both the colors spreading out and clearly-defined boundaries between
the color zones are caused by density gradients set up by the dissolving sugar. (Cf., Technical
Information below.) After about 10 minutes the M’s on the surface of the M&M’s will begin to
float. When you return to the Petri dishes after completing the next experiment, the color zones
should be complete and M’s should be floating.
Conclusions
Tell the students the following:
M&M’s® are candies which have a chocolate core covered with a layer of a sugar coating.
Sugar is actually a clear substance (it appears white in the sugar bowl because it’s actually
crystalline, and incoming light gets reflected in all directions to make it appear white), so food
coloring is added to give the various colors. As the sugar coating dissolves, both the sugar and
the food coloring dissolve in the water. But sugar water is heavier (i.e., denser) than regular
water, so it actually sinks and sets up little currents in the water. When one color zone runs into
another, the density is the same as from another zone. The tiny current stops and the colors don’t
mix. Of course, you could mix the color with your finger or, if you wait long enough just the
minor jostling the table’s receiving will be enough to mix the colors together.
By the way, the M on each M&M® is made of an insoluble TiO2 coating (also used in white
paint). As the sugar coatings dissolve, the M’s will float away. If you look closely, you’ll see
them floating around in the colored waters.
Technical Information (for the Demonstrator) 6:
The outer layer of an M&M® is almost entirely made of sugar. The majority of this layer is white
and only the outermost part of it is colored. Oh, and don't forget that sugar is actually a clear,
crystalline substance, and not really 'white'. A bowl of sugar looks white because all the grains
reflect white light in every direction, but pop a single grain under a microscope and it's clear, like
glass.
It also helps if you try the experiment with a single drop of food color in a dish of cold water.
You'll notice it does very close to nothing, so we can safely say that the food color in the
chocolate's shell is not causing the surprising result.
Place a sugar-coated M&M® into a shallow dish of water and what you're seeing is the outer
layer of sugar dissolving. As you know, the sugar solution produced is denser than pure water, so
6
http://www.abc.net.au/science/articles/2012/03/20/3459556.htm
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The Program: Experiment 5 – M&M Wheel & Floating M’s
Presenter’s Guide
it sinks and then spreads out. Scientifically speaking, what you see is a density gradient forming
between the sugar solution in the center of the dish and the pure water around the perimeter.
This density gradient causes a current— yes, like an ocean current— which flows away from the
higher sugar concentration in the center towards the area of low sugar concentration at the rim.
Once the outer layer of colored sugar has dissolved, the density gradient continues to push
sugary water towards the perimeter of the dish. Without food color to make this stage of the
proceedings visible, the color looks like it's magically attracted to the rim but it's actually the
remaining, uncolored sugar dissolving into the water that's making the magic happen.
So far, so good. But what's happening with the four chocolate cores?
You'll notice that the color spreads out and away from each chocolate in a semi-circular looking
fashion. Where they meet, the colorful currents appear to abruptly stop dead in their tracks.
The reason for the sudden pause in proceedings is, again, caused by density gradients. Initially,
the currents spread in every direction. But at the junction where any two colors meet, the
concentration of sugar (that is, the density of the solution) is equal on both sides. With no
difference in the density of the solution on either side, the density-driven current stops.
It doesn't really stop though. More sugar keeps dissolving away from each chocolate and piling
up at these junctions but you don't notice because sugar dissolves clear. If you carefully
measured the sugar concentration on either side of a junction, you would see it rising until all the
sugar has dissolved.
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The Program: Experiment 6 – Pop Rocks Rock
Presenter’s Guide
Experiment 6: Pop Rocks® Rock (Individual Experiment)
Experiment Purpose & General Methodology
For the demonstrator: In this experiment the sense of hearing comes into play. Some candy can
sound cool! We will put Pop Rocks® in water and watch the bubbling, and hear the fizzing.
This is due to the release of carbon dioxide as the hard candy dissolves around pockets of the
gas trapped at high pressure during manufacture.
Introduce the Experiment (SOUND)
Tell the students the following:
Look at your handout. We are nearing the end of our tour. We have one sense left. Ask: What is
it? (sound/hearing) Candy can delight our sense of sound. Ask: What kinds of sounds can candy
make? (whistling, crunching, bubbling….)
Some of these sounds, like crunching and whistling, are the result of physical action. Some
sounds are a result of a chemical reaction: like the fizzing of baking soda and vinegar as they
react to form carbon dioxide bubbles. Today we won’t be making carbon dioxide by a reaction,
but we will be releasing it from candy, and that makes a similar sound.
Have you ever heard of a candy called Pop Rocks®? Does anybody know what happens when
you put this candy in your mouth? If not, let’s find out, using an experimental method, rather
than by eating.
Performance Details
Tell the students to do the following:
Each person has two cups in front of them: one marked “W” containing water and a second one
marked “P” containing Pop Rocks and covered with a piece of waxed paper. Remove the waxed
paper cover. Then pour the water from the cup marked “W” over the contents of the cup marked
“P”. What’s happening?
Conclusions
Tell the students the following:
Could you hear the Pop Rocks® crackling in the water? Any idea what was happening?
Ans: Pop Rocks® are a form of hard candy. When the candy was made, the manufacturer
deliberately trapped pockets of a gas (carbon dioxide—the gas we expel whenever we breathe
out) under very high pressure. As the candy dissolves around the gas pockets, they burst with
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The Program: Experiment 6 – Pop Rocks Rock
Presenter’s Guide
the crackling/fizzing noise that you heard. This normally happens in your mouth, and it can
really make eating candy very interesting!
Demonstrator: Before going on to the next Experiment, return to the Conclusions section of
Experiment 5 and see if the color zones have formed. If they’re well formed, complete that
experiment. If not, return to Experiment 5 again after the last Experiment.
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The Program--Experiment 7 – A Candy Fountain
Presenter’s Guide
Experiment 7: A Candy Fountain (Group Demonstration)
Experiment Purpose & General Methodology
For the demonstrator: Modern carbonated beverages contain, among other things, CO2 dissolved
under pressure. Shaking the can will always release some of the “carbonation” in the form of
bubbles. In this experiment we’re going to see the effect of the addition of candy. Specifically, we
will add Mentos® to diet pop (diet, not regular, to cut down on ‘stickiness’). The spectacular,
rapid release of carbon dioxide occurs because this porous candy has many nucleation sites
where the dissolved gas can collect into larger bubbles that zoom to the surface. Mentos® are
heavy, too, so this effect occurs the whole time the candy falls to the bottom of the bottle.
If it’s a nice day, you might want to consider moving this experiment outdoors. Otherwise, be
sure to place the bottle in the middle of the plastic tray provided. The released pop shouldn’t
overflow this tray, but put some newspapers under it just in case.
Introduce the Experiment (SOUND continued and FINALE)
Tell the students the following:
We are at the end of our Candy Sense-ation Lab tour. Look at the handout and see how excited
our chemist is. Not because it’s the end, but because we have a grand finale! It will involve
sound, as well as have some good visual effects.
Ask: Have you heard of Mentos® candy? We will drop a piece into a bottle of pop.
Remember when we mixed candy with water it just dissolved. Pop is different from water
because it has, among other things, a dissolved gas called carbon dioxide.
What will happen is a physical process, not like mixing baking soda and vinegar. But still
chemical principles are at work!!
Performance Details
Tell the students to do the following:
We’re going to see what affect a piece of Mentos® candy has on the gas that’s dissolved in a
bottle pop. The Demonstrator will perform this experiment today.
Show the students the Mentos® candy which is glued to the underside of two plastic caps. Tell
them you’re going to remove the original cap on the pop bottle, replace it with one of the caps
with a Mentos® candy glued under it and then release the Mentos® candy into the pop using the
nail head. What do they think will happen? (This can be repeated once with the materials
provided.)
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The Program--Experiment 7 – A Candy Fountain
Presenter’s Guide
Conclusions
Tell the students the following:
What happened? Ans: the Mentos® caused the release of the dissolved gas from the pop. Using
the Mentos® to release the gas gives the same result as shaking the bottle and then opening the
cap—but we did it using chemistry without shaking.
Pop that we drink contains water, colorings, artificial flavorings and carbon dioxide gas to give
the pop “carbonation”. This gas has been dissolved in the pop under pressure, and some of it is
released immediately when we remove the lid.
Demonstrator: Remember to return for the conclusions of Experiments 5 & 6 when the fountains
are complete.
Technical Information (for the Demonstrator)
Mentos® is an exceptionally porous candy. Its insertion into the pop saturated with CO2 gives the
CO2 many nucleation sites with which to reform into a gas.
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Closing Session
Presenter’s Guide
Closing Session
• Remind the students that we need their help to determine which experiment they liked the
most. So vote for your favorite experiment AND the experiment that helped you learn some fun
facts about the chemistry of candy. Use your golf pencil to complete your Student Feedback
form now.
• Also tell them to make sure that they take home their handout with a list of library books and
websites that tell more interesting things about candy.
• Tell them to click on Contests! on the Cleveland Section’s web site (shown in the Handout)
for information on how to enter our Chemistry and Poster Contests where each student receives a
small token for entering and can win local and national cash prizes. You can also find us on-line
by searching under “Cleveland” and “National Chemistry Week”. (Note: there is no online
survey this year.)
• Tell the students that you hope they enjoyed our adventures with candy and you hope that
they’ve learned a lot.
• Before dismissing the students, ask the librarians and helpers to collect all unused candies;
clean out the Petri dishes and dispose of the “gummy worms”. Tell the students that each
individual student can take home their cleaned Petri dish and their chromatography strip. They
can’t have the gummy worms because we’re still afraid that they might eat them!
• Thank the students and parents for coming to this year’s demonstration and learning about
the chemistry of candy.
• Have the students come to the closing area to turn in their goggles and Student Feedback
forms. Have them put their goggles back into the box and then give it to the librarian for return
to Julia Boxler at the main library.
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Clean-up & Return Procedures
Presenter’s Guide
Cleanup & Return Procedures
A. General clean up procedures for experiments
•
•
•
All solid waste can be placed into a regular trash bag.
Any liquid wastes can be disposed of into sinks, toilets or the bucket that you brought.
Check with the librarian if they are willing to take the trash; otherwise, please dispose of
it with your own trash.
B. Returns
•
•
•
Other than goggles and Feedback and Photo Permission forms, the only items we’d liked
returned from this year’s library program are the golf pencils and the thermometer. You
may even discard the plastic trays.
Please complete the hardcopy Demonstrator Feedback form this year and return it in the
manila envelope address to Julia Boxler.
Place the completed Demonstrator and Student Feedback forms, the signed ACS Photo
Permission forms with a description of the photo to which it belongs and the golf pencils
and thermometer into the manila envelope labeled “Julia Boxler YTH”.
Please do not return ANYTHING other than these items!
C. Goggles:
•
•
If you are performing another demonstration for this year’s National Chemistry Week,
sanitize the goggles between demonstrations with a dilute bleach solution as instructed in
the written directions found on the underside of the cover of the goggle container. Be
sure to dry them with soft cloth or soft paper towels to prevent scratching. Please stack
them into their box without twisting or crushing!
If you are finished performing your demonstration(s) for this year, place the used goggles
into their box and give the box to the librarian for return to us through the Library system.
Please stack them without twisting or crushing! There is no need to clean them when you
are through; our Planning Committee will clean and sanitize them for the next year and/or
for other programs.
D. Before you leave the library
•
•
•
Return any items borrowed from the library.
Give any leftover literature to the librarian. (You may save a copy for yourself though!)
Give the manila envelope (containing completed forms and pencils) as well as the box of
goggles to the Children’s librarian with instructions to put it them in the interlibrary mail.
(Or take to your nearest CCPL library branch.)
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Clean-up & Return Procedures
Presenter’s Guide
At Home (Feedback)
•
If you took any photos to share (and have submitted signed permission forms to us),
please email them to Bob Fowler at [email protected]. Please note that any photos that
you care to share with us could end up on our web site and/or possibly with ACS if we
choose to use your photo in one of award self-nominations.
•
Smile! You may have expanded or even sparked scientific interest in a student today!
☺ ☺ ☺ ☺ ☺
THANK YOU!
☺
…for your participation in our program this year.
We hope you will join us next year too. Planning of experiments and contests starts in April.
You don’t have to be a teacher or scientist to join our Planning Committee; all you need is a
desire to share science with students. Development of ideas and refinement of experiments goes
on throughout the summer (a couple of hours every other week), donation gathering and
shopping is in late summer, and kit assembly (about 50 of them needing a lot of volunteer hands)
is on a Saturday in mid-September. It takes many, many volunteers to develop and put on all our
programs. Even a little bit of help goes a long way. Please contact us this year or next at
[email protected] if you (or a friend of yours) want to join in on the activities!
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Appendices
Presenter’s Guide
Appendices
A. Material Safety Data Sheets
Most MSDS’s (now called SDS’s—safety data sheets) can be found at
http://www.flinnsci.com/msds-search.aspx.
An MSDS for sodium alginate may be found at
http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en
&productNumber=W201502&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.si
gmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2Fw201502%3Flang%3Den
B. Supply list for recreating these experiments
Material resources for reproducing the experiments for items not found in your local
grocery/drug/hardware store:
•
•
•
•
•
Benedict’s solution, filter paper and pipettes may be ordered from several different
sources including Flinn Scientific at
http://www.flinnsci.com/store/Scripts/ck_prodList.asp, but it should be noted that Flinn
only ships to schools.
Alginate solution was purchased from Steve Spangler Science at
http://www.stevespanglerscience.com/search/product?q=worm.
Small metal thermometers (ETA hand2mind v-shaped) were purchased from Amazon at
http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&fieldkeywords=ETA+hand2mind+Vshaped+thermometers&rh=i%3Aaps%2Ck%3AETA+hand2mind+Vshaped+thermometers
Most of our candy was purchased in Cleveland from b.a.Sweetie Candy Company, 7480
Brookpark Road, Cleveland, OH 44129 or at www.sweetiescandy.com.
Pock Rocks candy was purchased from Dollar Tree stores at
http://www.dollartree.com/Pop-Rocks-3-ct-Packs/p141708/index.pro.
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