Nicole Martineau
Vocabulary Activity Plan
SCED 4300-001
Utah 7th Grade Science Core Standard 3: Students will understand that the organs in an organism
are made of cells that have structures and perform specific life functions.
Objective 1: Observe and describe cellular structures and functions.
d: Model the cell processes of diffusion and osmosis and relate this motion to the motion
of particles.
Essential Question: How do the processes of osmosis and diffusion affect living cells? Nice
focused question.
Vocabulary Words:
diffusion
osmosis
facilitated diffusion
active transport
concentration
equilibrium
gradient
hypertonic
hypotonic
isotonic
Activity #1: Introduction and Semantic Analysis
Using Think-Pair-Share, discuss the following questions with the students: If air freshener is
sprayed in the front of the room, will students in the back be able to smell it? What happens
when you place a wilting flower in water? Why? Demonstrate the first question by spraying
Lysol in the front of the classroom and asking students in the back when they can smell it.
Explain that particles and water are in constant motion towards equilibrium. The movement of
particles is called diffusion; the movement of water is called osmosis. I like how you first start
off with students’ everyday experiences and observations, and then connect them to the official
scientific principle. I am going to send you one of my favorite articles on science teaching…it’s
totally not required reading, but it reminds me a lot of your instruction. The whole point of the
article is that you need to draw from students’ funds of knowledge in science teaching, much as
you’re doing here.
Distribute the reading and ask students to highlight the following words when they find them:
diffusion, osmosis, facilitated diffusion, concentration, equilibrium, hypertonic, isotonic,
hypotonic, and gradient. Instruct students to then highlight the definition found anywhere in the
text near the highlighted word. Nice job of introducing the words in the context of an authentic
text.
After students have completed the reading, assign them to small groups (3-4) to complete the
Diffusion and Osmosis semantic feature analysis. Draw the analysis matrix on the board, and
with the class, fill it in and discuss the features of each.
Activity #2: Model Diagram
On the board, model the flow of particles and water between cells and hyper/hypo and
isotonic solutions. Throughout, ask students to hypothesize the movement of the particles or
water. Divide students into groups and instruct students to create a poster which will show one
picture of diffusion and two pictures of osmosis (one in which a cell is burst, and one in which a
cell is shriveling), and one picture of active transport. In this poster, students must accurately
depict the flow of particles or water using arrows, must title each picture “diffusion,” “active
transport,” or “osmosis,” and must label their solutions “hypertonic,” “hypotonic,” or “isotonic.”
Afterwards, students discuss their posters and share their examples with the other groups.
Activity #3: Potato Osmosis Lab
Remind students of proper lab attire and behavior and distribute copies of the Potato Osmosis
Lab (attached). Ask students to go to their lab stations and complete the lab set-up and lab
notebook entry – including the students’ hypotheses (using words like osmosis, mass increase,
mass decrease, concentration, gradient, hyper/hypo/isotonic) and methods summary. I really like
how you ask students to write an authentic text (e.g., lab results) using core vocabulary words.
Some research says that students produce better writing when they have the chance to talk about
their papers first. I wonder if, here, you could give students a prompt that says, “Explain what
happened in the lab using the following vocabulary words.” They could describe what happened
in the lab in a think/pair/share before putting their thoughts in writing. Just brainstorming ideas
here.
After 2 days, allow students to take their final measurements and write their conclusions in
their lab notebook (including the same vocabulary words from above). Students should be
specific about whether water or sugar particles moved, which way their moved, and why. Discuss
the lab results with the class. Draw the beakers and solutions on the board and review the results,
labeling which solutions were hyper/hypo tonic to the potato and the direction of the movement
of water into or out of the potato.
Activity #4: Quick Write
Give students the following prompt: “You are a researcher working in a biology lab on
human skin cells, and you have just hired a new lab assistant. In your lab, you have to keep your
skin cell samples alive and healthy, so you keep them in a slightly salty isotonic solution.
Explain to your new lab assistant why it is so important to keep the cells in an isotonic solution.
Convince her that it is very important that she does not add too much salt or too much water to
the cells by explaining what might happen if she does! Use the words osmosis, diffusion,
hypertonic, hypotonic, isotonic, gradient, concentration, and equilibrium to write your
instructions to your lab assistant.” Students should use all of the provided words, and should
describe each in detail to demonstrate their understanding. Again, excellent job of asking
students to use the words in the context of an authentic text. 
5/5: Let me know where you end up teaching! I want my daughter to take your chemistry class.
 Thanks for your description of absolutely top-notch instruction.
Rubric
Word Selection
The words you select are key
words that students would need
to know to engage in the
standard and essential question.
Contextualized
Instruction
Students have multiple
opportunities to encounter the
vocabulary words in context.
That means they may have
opportunities to write whole texts
using these words; conduct
Word Attack Strategies
or Showing Relationships
Between Words
You do at least one of the
following:
(1) Show students how the
words are related to each other
Students would have
multiple opportunities to hear,
read, and write these words as
part of natural instruction on this
standard.
The words are thematically
related to one another.
science experiments requiring
them to speak, listen and
investigate these words; use
manipulatives related to these
words; participate in simulations
related to these words; read these
words in the context of whole
texts; or otherwise encounter
these words as part of natural
instruction.
You chose 7(ish) words.
By the end of this unit,
students would have various
opportunities to develop in-depth
conceptual understandings of the
words.
The words you chose were
related to the standard but did
not represent key concepts.
The words may be loosely
thematically related.
You provide students with
some context for these words,
but students may not hear
multiple iterations of the
words in the activities that you
planned.
or to other concepts in your
discipline (e.g., through some
type of graphic organizer such
as the Frayer Model or
concept/definition map;
through Semantic Feature
Analysis, etc.).
(2) Teach students how to
use context clues or
morphemes to figure out
unknown words in the future.
You present words as
discrete, separate entities
without showing how they are
interrelated with students’
background knowledge or
with each other.
You chose more than 15
words, making it difficult for
students to remember them all.
Over half of your activities
You define the words
present the words out of the
without showing students how
context of meaningful
they might figure out
activities (e.g., flashcards,
unknown words in the future.
writing definitions from the
glossary).
The words you chose are not
thematically related to each other
and they are not essential to
engaging in the standard you
selected.
You present the words in
isolated, decontextualized
ways, such as asking students
to look the word up in a
dictionary.
Students will likely not
know the meaning of the
words by the end of this unit.
Diffusion and Passive Transport
By Regina Bailey
Diffusion
Diffusion is the tendency of molecules to spread into an available space. This tendency
is a result of the intrinsic thermal energy (heat) found in all molecules at temperatures
above absolute zero. Without other outside forces at work, substances will move/diffuse
from a more concentrated environment to a less concentrated environment. No work is
performed for this to happen, as diffusion is a spontaneous process.
Passive Transport
Passive transport is the diffusion of substances across a membrane. As we stated
above, this is a spontaneous process and cellular energy is not expended. Molecules
will move from where the substance is more concentrated to where it is less
concentrated.
As illustrated in the image above: "This cartoon illustrates passive diffusion. The dashed
line is intended to indicate a membrane that is permeable to the molecules or ions
illustrated as red dots. Initially all of the red dots are within the membrane. As time
passes, there is net diffusion of the red dots out of the membrane, following their
concentration gradient. When the concentration of red dots is the same inside and
outside of the membrane the net diffusion ceases. However, the red dots still diffuse
into and out of the membrane, but the rates of the inward and outward diffusion are the
same resulting in a net diffusion of O."- Steven Berg
Although the process is spontaneous, the rate of diffusion for different substances is
affected by membrane permeability. Since cell membranes are selectively permeable
(only some substances can pass), different molecules will have different rates of
diffusion. For instance, water diffuses freely across membranes, an obvious benefit
for cells
since water is crucial to many cellular processes. Some molecules however must be
helped across the cell membrane through a process called facilitated diffusion.
Facilitated Diffusion
Facilitated diffusion involves the use of a protein to transport molecules across the cell
membrane. Mariana Ruiz Villarreal
Facilitated diffusion is a type of passive transport that allows substances to cross
membranes with the assistance of special transport proteins. Some molecules and ions
such as glucose, sodium ions and chloride ions are unable to pass through the lipid
bilayer of cell membranes.
Through the use of ion channel proteins and carrier proteins that are embedded in the
cell membrane these substance can be transported into the cell. Ion channel proteins
allow specific ions to pass through the protein channel. The ion channels are regulated
by the cell and are either open or closed to control the passage of substances into the
cell. Carrier proteins bind to specific molecules, change shape and then deposit the
molecules across the membrane. Once the transaction is complete the proteins return
to their original position.
Osmosis
Osmosis is a special case of passive transport. These blood cells have been placed in
solutions with different solute concentrations. Mariana Ruiz Villarreal
Osmosis is a special case of passive transport. In osmosis water diffuses from a
hypotonic (low solute concentrated) solution to a hypertonic (high solute concentrated)
solution. Generally speaking, the direction of water flow is determined by the solute
concentration and not by the "nature" of the solute molecules themselves. If the blood
cells in the image above are placed in salt water solutions of different concentrations,
the following will occur:

If the salt water solution is hypertonic it would contain a higher concentration of
solute and a lower concentration of water than the blood cells. Fluid would flow from
the area of low solute concentration (the blood cells) to an area of high solute
concentration (water solution). As a result the blood cells will shrink.

If the salt water solution is isotonic it would contain the same concentration of solute
as the blood cells. Fluid would flow equally between the blood cells and the water
solution. As a result the blood cells will remain the same size.

If the salt water solution is hypotonic it would contain a lower concentration of solute
and a higher concentration of water than the blood cells. Fluid would flow from the
area of low solute concentration (water solution) to an area of high solute
concentration (the blood cells). As a result the blood cells will swell and even burst.
Accessed via:
http://biology.about.com/od/cellularprocesses/ss/diffusion_3.htm#step-heading
movement
of water
movement
of
particles
moves from high
concentration
to low
moves from low
concentration
to high
needs
membrane
proteins
needs
energy
movement
of water
movement
of
particles
moves from high
concentration
to low
moves from low
concentration
to high
needs
membrane
proteins
needs
energy
diffusion
osmosis
facilitated
diffusion
active
transport
diffusion
osmosis
facilitated
diffusion
active
transport
NAME _______________________________
LAB
MEASURING OSMOSIS: POTATO CORES
(Modified from Boulay, 2007)
INTRODUCTION
In this lab, different concentrations of sucrose solution will be poured over cores of
potato and allowed to sit overnight. Sucrose is a disaccharide, a large double-sugar
molecule that is unable to diffuse across cell membranes. It is composed of the
monosaccharides glucose & fructose. As the potato cores soak in the different sucrose
concentrations, they will either GAIN or LOSE mass, depending on the direction of
osmosis. Osmosis is the diffusion of water from an area of high concentration to an area
of low concentration.
What will determine the direction of osmosis? By graphing the % change in mass of the
potato cores in the different sucrose solutions, we will be able to determine the
concentration of the solution that is isotonic to the potato cores. At this concentration of
sucrose, the potato cores will neither gain nor lose mass.
Objectives


To measure osmosis in potato cores in varying concentrations of sucrose
To determine the isotonic solution of the potato cores &
the sucrose solutions via a graph
MATERIALS

6 plastic cups, potato(s), cork borer, balance, marker, razor blade, metric ruler,
sucrose sugar solutions: 0%, 4%, 8%, 12%, 16% & 20%
PROCEDURE – Day 1
1. Obtain 6 cups & label (using the marker) one of the sucrose concentrations on each
cup: 0%, 4%, 8%, 12%, 16% & 20%. Note that 0% is distilled water (dH2O).
2. Label your initials on each cup.
3. One partner can use the cork borer to cut 4 potato cylinders for each cup.
(24 cylinders total)
4. The other partner can trim each cylinder (using the razor blade) so it’s about 3 cm
in length. Try not to handle the cylinders more than necessary.
5. Use a scale (electronic balance) to find the mass (g) of each pile of 4 cylinders. Be
sure to "zero out" the cup each time before adding the 4 cores.
6. Record the mass on the Data Table as Initial Mass. Round to the nearest tenth
(0.1 g).
7. Swirl the 0% sucrose solution. Pour the 0% sucrose solution into the 0% cup.
Pour enough solution to just cover the potato cylinders.
8. Repeat Step 7 with the remaining solutions in the other cups.
9. Cover each cup with a plastic lid and let the potato cores sit overnight.
10. WASH & DRY all the tools you used today. Wipe down your lab bench with a
sponge.
11. What is the independent variable in this experiment?
---------------------------------------------------------------------------------------------------12. What is the dependent variable in this experiment?
---------------------------------------------------------------------------------------------------PROCEDURE – Day 2
13. Remove the potato cores from the 0% cup and place them on paper towel.
14. Gently blot them and quickly find their mass. Use the SAME scale you used on Day
1. Record this as Final Mass on the Data Table. Round to the nearest tenth (0.1
g).
15. Repeat this procedure for the remaining cores. Be sure to record all data.
16. Throw away the potato cores and all the cups (including the lids). Wipe down your
lab bench with a sponge.
17. Calculate the % change in mass for the potatoes in each cup using the formula
below. Show ALL your work for each cup in the table provided.
% Change in Mass
0%
=
(Final Mass
–
Initial Mass)
Initial Mass
x
100
4%
8%
12%
16%
20%
18. Record your individual % change in mass in the Data Table.
 Note that NEGATIVE %’s mean the potatoes LOST weight
19. Record your individual % change in mass on the computer spreadsheet as well.
20. Determine & record the class average % change in mass for the cores in each cup.
DATA TABLE
Cup Contents
0% Sucrose
(100% dH2O)
4% Sucrose
8% Sucrose
12%
Sucrose
16%
Sucrose
20%
Initial Mass (g)
Final Mass
(g)
Individual %
Change in Mass
Class Average %
Change in Mass
Sucrose
DISCUSSION
1. GRAPH – Use the graph paper on the back of this handout.




Label the X axis Sucrose Concentration
ABOVE the 0, label the Y axis % Increase in Mass of Potato Cores
BELOW the 0, label the Y axis % Decrease in Mass of Potato Cores
Label both axes with their proper Units
2. Graph your individual data. Connect the points with straight lines.
3. Graph the class average data in a different color. Connect the points with straight
lines.
4. Include a Key.
5. Give the graph a Title.
6. In which solutions did the potatoes GAIN mass? List them all. (Use the class data)
------------------------------------------------------------------------------------------------------Why did they gain mass?
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------7. In which solutions did the potatoes LOSE mass? List them all. (Use the class data)
------------------------------------------------------------------------------------------------------Why did they lose mass?
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------8. Do the following to calculate the concentration of sugar in the potatoes:

Locate the class average line



Put a dot where the class average line crosses the 0% change in mass
Draw a line down to the bottom of the graph from this point
What concentration of sugar does this line point to? ________
Explain why there was NO net gain or loss of mass at this concentration.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------9. Does equilibrium mean that water molecules stop moving? Explain.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------10. Why do you think we graphed the % change in mass rather than the actual change in
mass? (Think about the starting mass of all the cores)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------11. How do you think the surface area of the potato cores affects the data?
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------12. If you were in a hospital and had to have an I.V., would you prefer a solution that
diffuses into your cells, one that draws fluids out of your cells, or one at equilibrium
with your cells? Explain why. Be specific!
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------13. Discuss 3 places error could have occurred during this lab. Do NOT list human error.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------14. Was the movement of water into/out of the potato cores passive OR active transport?
Explain why.
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