LF-02 · TEACHER LESSON PLAN

Gummy bear osmosis

How a gummy bear changes in water and salt solution

BiologyGrades 5–8About 15 min active work on each of two days; 24 h soakHazard low; test candy, vinegar and spillsNGSS MS-LS1-2

01 //

Driving question

START THE LESSON WITH THISHow does the type of liquid a gummy bear soaks in change its mass overnight?

02 //

Learning objectives

Students prepare same-brand gummy bears in 100 mL each of distilled water, about 10% salt water and vinegar for a 24-hour soak.
Students measure starting and final mass to 0.01 g, calculate mass and percent change, and compare each bear's size before and after soaking.
Students model how water movement can change a gummy bear's mass while explaining why gelatin candy is only a limited model of a cell membrane.

03 //

Standards

Dimension	Alignment
Performance expectation	MS-LS1-2Develop and use a model to describe the function of a cell as a whole and ways the parts of cells contribute to the function. (Partial alignment: this lab does not list a performance expectation; MS-LS1-2 is the closest match because a gelatin gummy bear is a limited model of how a membrane-bounded cell gains or loses water. Gummy bears have no living cell membrane, so the activity does not model cell parts.)
Practices	SEP 3Plan and carry out investigations. SEP 4Analyze and interpret data.
Core idea	LS1.AWithin cells, special structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell.
Crosscutting	Structure and functionComplex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function.

Standards text paraphrased from nextgenscience.org. Alignment is partial; this hands-on activity does not cover every part of the performance expectation.

03A //

State standards crosswalk

Use the row as a planning crosswalk, then confirm local district pacing and grade placement. “Partial” labels describe a skill connection, not full mastery of the complete standard.

State	Verified standard	How this lesson aligns	Official source
California	CA NGSS MS-LS1-2	Partial model connection. The bear's mass change can prompt a water-movement model, but gelatin candy has no cell membrane or cell parts and cannot demonstrate the whole-cell expectation.	Open standard ↗
Texas	Science.8.13(A)	Limited model connection. The standard identifies cell-part functions, while a gummy bear has no membrane or organelles; use the candy only to discuss limits of a visible water-movement model.	Open standard ↗
Florida	SC.6.L.14.4	Partial model connection. This activity compares mass changes in candy rather than describing the structures and functions of the cell parts named by the benchmark.	Open standard ↗
New York	NYSSLS MS-LS1-2	Partial model connection. Students discuss water movement and model limits, but the candy has no living cell membrane and does not represent a whole cell or its parts.	Open standard ↗
Pennsylvania	STEELS 3.1.6-8.B	Partial model connection. The measured candy response can support discussion of model limits, but it cannot show cell parts or the function of a living cell as a whole.	Open standard ↗

04 //

Materials and prep timeline

PER GROUP

Three same-brand, same-color gummy bears
Three labeled cups and a tray
100 mL each of distilled water, 10% salt solution and vinegar
10 g table salt and up to 100 mL extra distilled water to prepare the salt solution
Balance readable to 0.01 g, ruler, spoon and paper towels
Labels, timer and recording sheet

TEACHER ONLY

Check ingredient labels for allergies and keep small candies away from young children. Students must not eat bears after soaking or handling them.
For a 10% mass-per-volume salt solution, dissolve 10 g salt and add distilled water until the final solution volume is 100 mL. Use equal 100 mL liquid portions and room-temperature conditions.
Place cups on a tray where they can remain undisturbed for 24 hours. Set teacher-directed disposal for salt water and vinegar, and provide handwashing supplies.

CLASS-SIZE KIT PLANNER

One per-group kit contains every item in the team materials list above. Groups are balanced around the listed 3–4 students target.

Students	Groups	Per-group kits	Student sheets	Suggested group split
20	6	6 complete kits	20 copies	2 groups of 4 and 4 groups of 3
25	7	7 complete kits	25 copies	4 groups of 4 and 3 groups of 3
30	8	8 complete kits	30 copies	6 groups of 4 and 2 groups of 3

DAY 1 SETUP — ABOUT 0–5 MINPredict and label

Predict which liquid may cause the largest mass increase or loss. Label water, salt water and vinegar cups; review allergies, no tasting and handwashing.

DAY 1 SETUP — ABOUT 5–15 MINMeasure and begin the soak

Use same-brand bears, record each starting mass and longest length, add 100 mL of the assigned liquid per cup, then soak undisturbed for exactly 24 hours.

DAY 2 RESULTS — ABOUT 0–6 MINRecover and blot

Use a spoon to lift each bear, blot all bears the same way and record final mass to 0.01 g and final length without squeezing the softened candy.

DAY 2 RESULTS — ABOUT 6–12 MINCalculate changes

For each bear, calculate final minus starting mass and divide mass change by starting mass for percent change. Record size observations.

DAY 2 RESULTS — ABOUT 12–15 MINCompare and clean

Compare all three liquids and discuss the model's limits, especially vinegar's effect on gelatin. Do not eat test bears; wash hands and dispose of liquids as directed.

04A //

Lab figures and data visuals

Reviewed article images support the lesson flow. Use the tables and student sheet to record actual observations; pictured patterns are not target results.

Matched gummy bears are measured before and after a 24-hour soak in plain water, salt water or vinegar, with consistent blotting. — **Measure before and after soaking.**Keep liquid volumes and soak time matched; blot every sample the same way before weighing.

A cutaway gummy bear shows a gelatin network taking up water, with a clear warning that it is not a living cell membrane. — **Use a limited gel model.**Gummy candy is gelatin, not a cell; its mass and shape changes are a limited model of water uptake.

A blank percent-mass-change graph compares water, salt water and vinegar while leaving all outcomes to students' data. — **Graph the measured results.**Use the zero line to distinguish mass gain from mass loss; do not assume every candy behaves the same way.

04B //

Printable shopping list

TEACHER PREP · Gummy bear osmosis

Shopping and staging checklist

Multiply the per-group kit contents by the class-size planner. The teacher section includes teacher-provided materials and setup or safety notes.

PER-GROUP KITS

Three same-brand, same-color gummy bears
Three labeled cups and a tray
100 mL each of distilled water, 10% salt solution and vinegar
10 g table salt and up to 100 mL extra distilled water to prepare the salt solution
Balance readable to 0.01 g, ruler, spoon and paper towels
Labels, timer and recording sheet

TEACHER-PROVIDED MATERIALS + SETUP RULES

Check ingredient labels for allergies and keep small candies away from young children. Students must not eat bears after soaking or handling them.
For a 10% mass-per-volume salt solution, dissolve 10 g salt and add distilled water until the final solution volume is 100 mL. Use equal 100 mL liquid portions and room-temperature conditions.
Place cups on a tray where they can remain undisturbed for 24 hours. Set teacher-directed disposal for salt water and vinegar, and provide handwashing supplies.

QUANTITIES BY CLASS SIZE

Material	Per group kit	20 students	25 students	30 students
Same-brand gummy bears	3 bears	18 bears	21 bears	24 bears
Labeled cups and tray	3 cups and 1 tray	18 cups and 6 trays	21 cups and 7 trays	24 cups and 8 trays
Distilled water for control and brine prep	Up to 200 mL	1.2 L	1.4 L	1.6 L
Prepared 10% salt solution, mass per volume	100 mL	600 mL	700 mL	800 mL
Table salt for 10% solution	10 g	60 g	70 g	80 g
Vinegar	100 mL	600 mL	700 mL	800 mL
Balance, ruler and spoon	1 set	6 sets	7 sets	8 sets
Labels, paper towels and timer	1 set	6 sets	7 sets	8 sets
Student data sheets	1 per student	20 copies	25 copies	30 copies

Prepare 6 kits for 20 · 7 kits for 25 · 8 kits for 30 students.

05 //

Lesson flow

Minutes	What happens
Day 1 setup — about 0–5 min	Engage Predict the liquid expected to change gummy-bear mass most. Label the three liquids and review allergies, no tasting and handwashing.
Day 1 setup — about 5–15 min	Explore Record starting mass and longest length for same-brand bears. Place one in each 100 mL liquid sample and leave the cups undisturbed for 24 hours.
Day 2 results — about 0–6 min	Explore Lift each bear with a spoon, blot in the same way and record final mass to 0.01 g and longest length without compressing it.
Day 2 results — about 6–12 min	Explain Calculate mass change and percent change from each bear's starting mass. Compare the size observations with the mass data.
Day 2 results — about 12–15 min	Evaluate Explain water movement and the limits of candy as a cell model. Do not eat test bears; wash hands and follow teacher directions for liquid disposal.

06 //

Discussion questions

1. Why does a gummy bear usually gain mass in distilled water?

SAMPLE ANSWERThe gelatin candy contains concentrated dissolved sugar. Water can move into its porous gelatin network, increasing its mass and often its size.

2. Why might salt water reduce the mass gain or make a bear lose mass?

SAMPLE ANSWERSalt water has dissolved solute outside the bear. That concentration difference can reduce inward water movement or draw some water out; the result depends on the bear and the salt concentration.

3. Why can vinegar make a bear soft or partly dissolve it?

SAMPLE ANSWERVinegar is mildly acidic and can affect gelatin as well as the movement of water. A vinegar result should not be explained by osmosis alone.

4. How is a gummy bear different from a cell?

SAMPLE ANSWERIt has a gelatin network but no living cell membrane or cell parts. It can model a visible change in water content only in a limited way.

07 //

Common misconceptions

STUDENTS OFTEN SAY“A gummy bear is a cell with a membrane.”

BETTER IDEAIt is a gelatin candy without living cell parts or a cell membrane, so it is only a limited model of water movement.

STUDENTS OFTEN SAY“Vinegar mass change proves osmosis is the only process.”

BETTER IDEAVinegar can soften or partly dissolve gelatin, so its effect can include changes beyond water movement.

STUDENTS OFTEN SAY“The soaked bear is still a snack because it started as candy.”

BETTER IDEAThe samples have been handled in lab liquids and must not be eaten. Check allergies, discard them as directed and wash hands.

08 //

Differentiation

SUPPORT

Provide pre-labeled cups and a balance checklist for tare, starting mass, blotting and final mass.
Use a calculator and a worked example for change = final − start and percent change = change ÷ start × 100.
Offer the frame: “The bear in __ changed from __ g to __ g, a __% change; its length changed from __ to __ cm.”

EXTEND

Repeat with additional bears from the same bag and compare the range of percent changes for each liquid.
Measure width as well as longest length and explain why an irregular soft bear is difficult to size consistently.
Test a second salt concentration while keeping liquid volume, bear type, room temperature and soak time at 24 hours.

09 //

Assessment rubric

Criterion	Beginning	Developing	Secure
Matched soak	Does not label liquids or uses unmatched soak times.	Labels all liquids but misses equal volume or same-brand bears.	Uses same-brand bears in 100 mL samples and records a 24-hour soak in all three liquids.
Mass and size	Leaves starting or final measurements blank.	Records mass but omits units, consistent blotting or size observations.	Records start and final mass to 0.01 g, longest length in centimeters and consistent blotting.
Calculations	Does not calculate changes or uses the wrong starting value.	Calculates mass change or percent change but not both correctly.	Calculates final-minus-start mass and percent change using starting mass for each bear.
Explanation and safety	Treats the candy as a living cell or eats a test bear.	Explains water movement but ignores vinegar effects or allergy precautions.	Uses mass evidence, notes vinegar and model limits, avoids tasting and washes hands after handling.

10 //

Vocabulary

Osmosis – Net movement of water across a selectively permeable boundary.
Solute – A substance dissolved in a liquid, such as sugar or salt.
Concentration – The amount of dissolved substance in a stated amount of liquid or solution.

Percent change – The change divided by the starting value, multiplied by 100.
Model – A representation that helps explain a system but has limits.
Gelatin – A protein material that forms the flexible network in gummy candy.

11 //

Safety, cleanup and troubleshooting

BEFORE STUDENTS TOUCH ANYTHING

Do not eat gummy bears after they have been soaked or handled. Check ingredient labels for allergies and keep small candies away from young children who could choke.
Use cups on a tray, clean spills promptly and wash hands after handling samples. Avoid splashes when pouring vinegar, and keep liquids away from eyes and mouths.
Keep cups labeled and undisturbed for 24 hours. Dispose of salt solution and vinegar according to teacher directions; do not taste any liquid or sample.

Troubleshooting: If a bear tears or partly dissolves, especially in vinegar, record the observation and do not force it onto the balance. Blot each bear using the same gentle method; if it is too soft to handle, note the measurement as unavailable. Do not extend the soak past 24 hours, and discard all test bears as directed.