The Science Demo Gems Collection
Presenter: Milan Sanader
The following collection of demos and class activities are intended for grades 9 and 10. Please share
these with your colleagues and consider adding your favourite activities to the STAO Virtual Library- the
STAO online resource collection. Always model the safety practices you expect of your students when
you conduct a demo.
Physics Strand Activities
Squishy Circuits
Topic: circuit electricity
The salt content of Playdough makes it a good conductor. Other recipes for Playdough provided at the
site given below use sugar rather than salt. This increases the resistance of the final product. Simple
circuits can be constructed using Playdough.
http://courseweb.stthomas.edu/apthomas/SquishyCircuits/
Energy Ball
Topic: Current electricity
This ball contains two small metal electrodes. When the electrodes are touched simultaneously, the
Energy Ball flashes and makes a buzzing sound. A great group activity is to have the participants hold
hands. Have one participant touch one of the electrodes while another person at the other end of the
circle touches the other electrode. Two people can touch the electrodes and make the Energy Ball buzz
as long as everyone around the circle is holding hands.
http://www.youtube.com/watch?v=qAIUQSDKxlo
http://www.youtube.com/watch?v=pgT_9a5jMqM&feature=related
STAO Online Current Electricity Workshop
http://stao.ca/scienceworks/CEW-Intro.php
This collection of resources is free to download. However, registration is required.
Static Cling
Topic: electrostatics
Mark a large “X” on an inflated balloon. Rub the side of the balloon opposite the X in your hair. Stick
the balloon onto a wall. Without touching the side you rubbed, rotate the balloon and attempt to stick
the “X” side of the balloon to the wall. The balloon doesn’t stick because the excess of charge is localized
on the other side and not evenly distributed over the entire surface of the balloon. Activities involving
static electricity are greatly affected by humidity. For best results, try to schedule this portion of the
course in the colder dryer months of the school year.
Generating Your Own Electrical Energy
Topic: current electricity
Take apart a hobby electric motor and identify its important parts (e.g., magnets and coiled conductor).
Reassemble the motor. Attach the motor to a galvanometer. Rotate the shaft and note what happens
to the needle of the galvanometer. Vary the speed and direction of rotation to determine how these
factors affect the current generated. Hand-cranked generators can also be used to light a small bulb.
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
1
Blind Spot
Topic: refraction
A small dot about 3 mm in diameter is placed on a card. The letter “X” is drawn (about the same size)
about 6 cm to the right of the dot. Hold the card at arm’s length. Close your right eye and look at the
“X” with your left eye. You should also be able to see the small dot out of the corner of your eye. Keep
your eye focused on the “X” and slowly bring the card toward you. At a certain point, the dot disappears
(your blind spot). Continue moving the card towards you and the dot reappears.
A Crunch that Glows Topic: conversion of mechanical energy to light energy
Quickly crush a wintergreen lifesaver in a totally dark room. A flash of light is observed. This conversion
of mechanical energy to light is a phenomenon known as tribololuminescence.
http://www.youtube.com/watch?v=0brmw8sP-Js&feature=related
Test tube breeding liquid
Topic: index of refraction
This activity requires two small Pyrex test tubes that have no markings. Before the demo, completely fill
one test tube with glycerine and place it in a 1 L beaker containing about 300 mL of glycerine. The test
tube is almost invisible because glycerine and Pyrex have identical indices of refraction. Then, when
your students are present, add the second test tube to the beaker. However, don’t fill the test tube.
Remove the second test tube. Then, magically, remove the “hidden” test tube.
http://www.youtube.com/watch?v=wlELYZJ5JF4&feature=related (This video uses Wesson cooking oil
instead of glycerine)
Bending Light part
Topic: Total internal reflection
Poke a hole in the side of a large soft drink bottle. Seal the hole with tape and fill the bottle. Remove
the tape to produce a steady stream of water. Point a laser pointer at the hole from the opposite side of
the bottle. The laser light follows the stream of water.
http://www.youtube.com/watch?v=hBQ8fh_Fp04&feature=related
http://www.youtube.com/watch?v=s7w1Z1FCgwA&feature=related
Chemistry Strand Activities
Safety Resources
STAO has developed a series of six safety videos that cover most lab hazards involving chemicals or
flames. They should be available for free download from the STAO website soon. Topics include:
• collecting and testing for gases
• the reaction of alkali metals in water
Elephant Toothpaste Topic: decomposition reactions, green chemistry
Place a volumetric flask in a large tub. Fill much of the lower portion of the flask with 6% hydrogen
peroxide. Add a few squirts of liquid detergent. Add about ½ teaspoon of dry yeast.
What happens?
Yeast catalyzes the decomposition of hydrogen peroxide into water and oxygen gas. Yeast is a greener
alternative to traditional catalysts used for this reaction (e.g., MnO2, KI).
http://www.youtube.com/watch?v=4N0m95PExHY&feature=related
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
2
Gack Topic: Physical Properties
Gack is a viscous mixture of corn starch and water. Add about a teaspoon of cornstarch to the palm of
your hand. Slowly add water and mix until the mixture has the consistency of a viscous paste.
What Happens: Under pressure, the paste feels solid. It becomes a "runny" fluid again once the
pressure is released. The application of pressure forces the polymer chains in the starch to align,
increasing the likelihood of intermolecular attractions. These attractions break once the pressure is
released. Two interesting demonstrations of gack can be found at:
http://www.youtube.com/watch?v=hMvxYuZpDpk&feature=fvsr
http://www.youtube.com/watch?v=RUMX_b_m3Js
Designs and Detergents
Topics: physical properties, e.g., surface tension
Add 4 drops of different colours of food colouring to a plate of tap water. Soak a cotton swab into in
liquid detergent. Dip the swab into the middle of the drops and hold it there for about 10 s.
Repeat with milk.
What happens?
Soaps and detergents are large ionic compounds that can disrupt the hydrogen bonds between water
molecules. Since milk is mostly water, you would expect soap to have the same effect on milk. However,
milk also contains proteins and fat. Protein molecules form hydrogen bonds with water molecules. Fats
do not attract water. Rather, fat molecules clump together in microscopic globules within the milk. Fat
molecules also form attractions with the hydrophobic hydrocarbon chains of the soap ions. These
attractions result in considerable molecular motion, resulting in some spectacular colour blending. If
you really want to be creative, vary the amounts of each colour and where the colour is added. For an
example of what can be done see:
http://www.youtube.com/watch?v=pW-bn9zssak&feature=related
The Penny Stretch
Topics: physical properties, e.g., surface tension
This is a fun activity to use early in the strand or even on the first day of school to reactivate inquiry
skills.
Procedure:
• Place an empty wine glass in a shallow plastic tub.
• Fill the wine glass to within 1-2 mm of the rim with tap water.
• Ask students to predict how many pennies can be added to the glass without overflowing.
• Have a volunteer add pennies
What Happens?
As pennies are added, students notice that the water level “domes” above the rim of the glass. This is a
result of surface tension. As many as 40-60 pennies can be added to the glass. This demo can be
followed by a student activity in which students attempt to put as many drops of water as possible on
the surface of a penny. In the process, they brainstorm possible factors that influence the number of
drops that the penny can support.
http://www.youtube.com/watch?v=tv4Jrc06yLA&feature=related
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
3
Fizz n flame evidence of a chemical change
Procedure:
• Light a small tea candle.
• Use tongs to transfer the candle to a beaker.
• Add a teaspoon of baking soda to another beaker.
• Slowly add vinegar to the baking soda beaker. Tilt the beaker such that carbon dioxide can flow
from it into the beaker containing the candle.
What Happens?
The reaction of baking soda and vinegar produces carbon dioxide gas. The flame is slowly
extinguished as carbon dioxide gas invisible sinks into the beaker. This shows that carbon
dioxide is less dense than air and that it does not support combustion.
Collapsing Can Topic: air pressure
Add about 10-20 mL of water to an empty soft drink can. Bring the water to a boil. After steam has been
observed for about 10-15s, quickly invert the can and immerse the opening into a pan of cold water.
What happens: The can quickly collapses because the atmospheric pressure is greater than the air
pressure inside the can.
This is an amazing video clip of a rail car collapsing under vacuum. The tank had a vent designed to
release pressure, not vacuum. Also, since the tank was designed for internal pressure, it had no vacuum
support rings. The rail car had just been steamed out and it was still hot inside when it started to rain.
The cool rain caused sufficient vacuum to suddenly and completely collapse the tank.
http://www.youtube.com/watch?v=Uy-SN5j1ogk
http://www.youtube.com/watch?v=2WJVHtF8GwI&feature=related
Out Goes the Salt
Topic: physical properties, electrical conductivity
This activity is useful to introduce ionic compounds and deal with the common misconception that
“water conducts electricity”.
Procedure:
• Use a low current conductivity tester to test the conductivity of distilled water.
• Pour a small volume of distilled water into the palm of your hand and swirl it for a few seconds.
This allows salt on the surface of your skin to dissolve in the water.
• Dim the lights and test the fluid in your hand for electrical conductivity
What Happens?
Since pure water is a nonelectrolyte, no evidence of conductivity is initially observed. Distilled
water in the palm of your hand conducts due to electrolytes on the surface of your skin.
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
4
Halt the Salt
Topic: physical properties, nutrition
Procedure:
• Students compile the sodium content of a breakfast, lunch and dinner consisting only of
processed foods
• This data is compared to sodium content of equivalent meals of unprocessed foods
What Happens?
The processed food salt content is often three times the daily accepted intake of sodium.
Pop Rocks
Topics: evidence of chemical change, formation of an acid
Pop rocks are hard candy that contains trapped CO2. Pop rocks are made by heating hard candy until it
melts and then pumping pressurized carbon dioxide into it. As the candy cools and solidifies, bubbles of
carbon dioxide become trapped inside the candy. A sudden release of pressure to room conditions
causes the candy to shatter into tiny pieces. As the candy dissolves in your mouth, carbon dioxide is
released, creating a popping sound. Pop Rocks can be purchased at many dollar stores and party supply
stores.
Procedure:
• Half fill a Petri dish with water.
• Place the dish on an overhead projector. Add enough bromothymol blue indicator to colour the
water a noticeable blue.
• Sprinkle about ¼ package of Pop Rocks in dish.
• If a projector is not available, half-fill a 1 L flask with water. Add enough bromothymol blue
indicator to colour the water. Add about ½ package of Pop Rocks and swirl to mix.
What Happens?
Carbon dioxide released from the candy combines with water to form carbonic acid. The
increased acidity of the mixture causes the indicator to change from blue to yellow.
http://www.youtube.com/watch?v=-QiXePPTvBo
Nomenclature Cut-Outs
Topic: Nomenclature
Ion cut-outs are a great tool to help students see why the sum of the ionic charges in the chemical
formula of an ionic compound is zero. They are also useful for students who may need a quick review of
chemical formula. (See attached)
Procedure:
Students use the cut outs to determine the correct chemical formula of a series of ionic compounds,
e.g., NaCl, Na2O, Na3N, etc. The correct formula is achieved when all charges are balanced.
What Happens?
Students soon realize how to determine the chemical formula without the aid of cut-outs.
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
5
Can Ripper Topics: evidence of chemical change, single displacement reactions, metal corrosion
Caution: Copper(II) chloride is toxic. Avoid skin contact.
Procedure:
• Use a sharp object (e.g., nail) to score a line around the interior circumference of a soft drink
can. This cuts the plastic liner on the inside of the can.
• Place the can in a plastic pan to contain spills.
• Pour 0.5 mol/L copper(II) chloride into the can to a height that is slightly above the line. Wait
for about 5 minutes for the oxidation of aluminum to occur.
• Carefully pour off the solution and reuse it. Rip the can apart.
What Happens?
How it works: The copper ion, Cu2+(aq) oxidizes aluminum, weakening the can enough for you to pull it
apart. The reaction doesn’t work if copper(II) sulfate is used.
Defoaming Styrofoam Topic: physical and chemical properties
Procedure:
• Add about 100 mL of acetone to the large beaker.
• Add a Styrofoam cup to the acetone. Push the cup into the acetone.
• Use a spoon to remove the polystyrene residue that is produced.
(Caution: acetone is flammable)
What Happens?
Acetone breaks down the structure of the polystyrene polymer in the cup, causing a drastic
reduction in the volume of the cup. The bubbles observed in the demo result from air trapped
within the polymer.
http://www.youtube.com/watch?v=gXjKYuD_AlY
Milk of Magnesia Neutralization
chemical reactions
Topic: acids/bases, neutralization, reversibility of some
Milk of magnesia is a suspension of magnesium hydroxide. Because Mg(OH)2 is insoluble, the
concentration of hydroxide ions in the suspension is very small. The colours of universal indicator
are:
1. Very acidic – Red 2. Acidic - Orange/Yellow 3. Neutral – Green 4. Basic/base/alkali - Blue
5. Very basic/base/alkali - Purple
Procedure:
• Add about 400 mL of water, half a teaspoon of milk of magnesia, and a squirt of bromothymol
blue indicator to the large flask.
• While stirring continuously, gradually add a dilute hydrochloric acid solution until the flask
contents have been neutralized.
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
6
What Happens?
The initial indicator colour is blue. Each addition of acid changes the suspension colour to green and
perhaps orange/yellow before returning to blue or blue/green. Eventually, all the hydroxide in
Mg(OH)2 is neutralized. If an excess of acid is added, the solution turns yellow to red and becomes
transparent.
http://www.youtube.com/watch?v=dwNboZesSs4
Visualizing the pH scale
Topic: acidity, pH scale
This activity is useful to show a small change in pH results in a significant change in the acidity of a
solution.
Procedure:
• Place a clean dry well plate on the overhead projector.
• Add one drop of blue food colouring to a well in a well plate. The intensity of the blue colour is
used to represent an acid with pH 0.
• Add one drop of blue colour and 9 drops of water to the second well. Mix well.
• Add one drop of the mixture in well #2 to well #3. Add 9 drops of water and mix well.
• Continue the dilutions until the blue colour is no longer visible.
What Happens?
The concentrated food colouring can be used to represent a solution of pH 0. Therefore, the second and
third wells correspond to pH 1 and 2, respectively. Students see that only a few successive dilutions are
needed for the blue colour to no longer be visible. This dramatically shows that each step along the pH
scale corresponds to a significant change in acidity.
Biology Strand Activities
Human population Clock
Topic: human ecology
The website shows a real time estimate of the human population. Start it at the beginning of your class
and see how much the human family has increased by the end of the period.
http://math.berkeley.edu/~galen/popclk.html
Selective Solubility
Topic: bioamplification
This can be used to show the selective solubility of fat soluble pesticides like DDT.
Add a small volume of Lugol’s solution (a mixture of I2, KI and water) to a mixture of water and mineral
oil in a test tube. Mineral oil is used to simulate fat tissue. Shake and allow the contents to settle.
What Happens?
The iodine in the Lugol’s solution dissolves in the mineral oil layer but not in the water layer.
Arable Land Limitations
Topic: ecology
This activity is useful to show students how little soil exists on the surface of the Earth. An apple is used
to represent the Earth Cut an apple into four quarters. Discard three quarters. The remaining quarter
represents the dry land on Earth. Cut away and discard about 4/5th of this quarter. The skin of the
remaining piece represents the area of the Earth’s surface suitable for food production.
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
7
Earth and Space Strand Activities
STAO Online Climate Change Workshop
This collection of resources is free to download. However, registration is required.
http://stao.ca/scienceworks/SOW-Intro.php
Constellation Connections
Provide students with a star chart. Instruct each pair of students to connect the “dots” to form random,
inspired images. This activity is useful to show that the shapes of the constellations are arbitrary.
Model the Expanding Universe
This activity is provides students with a concrete analogy to help understand the concept of an
expanding universe. Fill a balloon with air until it is the size of a large apple. Mark four dots on the
balloon, about 1 cm apart so that the dots form a square. Label the dots A, B, C, and D. Measure the
exact distance between the dots. Inflate the balloon to the size of a volleyball. Measure the distances
between the dots.
Video Materials
Fun but too dangerous:
Gr. 10, 11 Types of Chemical Reactions
a) Synthesis of NaCl from its elements
http://www.youtube.com/watch?v=Mx5JJWI2aaw
b) Decomposition of nitrogen triiodide
http://ca.youtube.com/watch?v=2KlAf936E90
c) Single displacement reactions of the alkali metals
http://ca.youtube.com/watch?v=m55kgyApYrY - Brainiac
d) Double displacement reactions: Silver nitrate and sodium hydroxide
http://www.youtube.com/watch?v=SuoN0hQPeMw&feature=related
Other useful online material:
1. Conductivity Tester
The conductivity tester shown below costs less than $3 to assemble and is very effective. Instructions
for making a simple tester can be found at:
http://atlantis.coe.uh.edu/texasipc/units/energy/conductivity.pdf
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
8
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
9
STAO 2011 – Hands-on Inquiry-based Activities That Will Engage Students in the Applied 9-10 Science Classroom
(SNC1P & SNC2P)
Session #1120
Presenter: Milan Sanader
www.facebook.com/nelsonschoolsciencek12
10