Name:______________________________________ Date: ____________ Period: ______
Purpose
To investigate osmosis (the movement of water) into and out of a polymer.
Background
Gummy bears are made of gelatin and sugar. Gelatin is a polymer that forms large threedimensional matrices, which give structural support to jellies and jams. The movement of water into or out of a Gummy bear is very similar to how water enters and leaves living cells.
Testable Question
How will soaking Gummy bears in tap water, distilled water and salt water affect the mass (and overall size) of a Gummy Bear?
Variables
Manipulated variable: type of liquid that Gummy bears are placed in
Responding variable: mass (and overall size) of the Gummy bears
Controlled variables (4+): initial size of Gummy bear, brand of Gummy bear, color of Gummy bear, amount of liquid, type of cup, environment
Hypothesis: If Gummy bears are soaked in different solutions, then the Gummy bear soaked in tap water will…, the Gummy bear soaked in distilled water will… and the Gummy bears soaked in salt water will… because…
Materials o (2) Gummy Bears o (2) plastic cups (16 oz) o 100 mL graduated cylinder o Centimeter ruler o Distilled water o Tap water o o
Saturated salt solution
Paper towels o Aluminum screen o Weigh boats o Balance o Labeling tape (2 pieces)

Procedure: Day 1
1.
Obtain two plastic cups and two bears of the same color.
2.
On one piece of labeling tape, write “Bear 1,” “Tap Water,” your group member’s names, today’s date and the class period using a writing utensil.
3.
The other piece of labeling tape should indicate “Bear 2,” “Distilled Water,” your group member’s names, today’s date and the class period.
4.
Place the bears in the cups.
5.
Find the mass of each bear using a balance. Record the data in the data table.
6.
Measure your bears from top to bottom (height), from side to side (width) and from front to back (depth). Use your measurements to calculate the volume (h x w x d). Record your data in the data table. Measure the values for each one separately, since they may have different measurements.
7.
Measure 70 ml of tap water and pour into cup “Bear 1”.
8.
Measure 70 ml of distilled water and pour into cup “Bear 2”. Never return distilled water back into the original container, as it may get contaminated.
9.
Place the cups on the counter on the periphery of the classroom and let them soak overnight.
Procedure: Day 2
10.
On the next lab day, gently pour the water from each cup over a sink.
11.
Catch each bear on a piece of paper towel. While on the towel, measure the height, width, and depth. Calculate the volume. Record your data.
12.
Blot the bear dry by using paper towel.
13.
Find the mass of each bear. Do this by placing measuring the bear IN A WEIGH BOAT on the balance. Record the total mass. Carefully slide the bear back into the empty cup.
14.
Cover the bears with 70 ml of saturated salt solution. Let this sit over the weekend.
15.
Rinse out your graduated cylinder and return all materials to their respective locations.
Procedure: Day 3
16.
Create an experiment. You get two Gummy bears and access to various solutions. Write the procedure after your Data Table. Once Mr. Ashley checks off your Day 3 procedure create a data table to support your experiment.
17.
On the third lab day find the mass and dimensions of the bears using same procedure as the previous day, and record. Calculate the volume.
18.
CONDUCT your Day 3 experiment!

Data Table:
Dimensions Soaking
Height (cm)
Width (cm)
Depth (cm)
Volume (cm 3 )
Mass (g)
(day 1)
Gummy Bear 1 (Tap water)
Before After tap After salt water
(day 2) water
(day 3)
Data Analysis
Gummy Bear 2 (distilled water)
Before After After salt water
(day3) soaking
(day 1) distilled water
(day 2)
1.
Calculate the percent change in volume after each step of the experiment.
% change in volume = final volume - initial volume x 100 initial volume
Analysis
Bear 1 Bear 2
% Change in Volume
From Day 1 to 2
(soaked in water)
% Change in Volume
From Day 2 to 3
(soaked in salt solution)
% Change in Volume
From Day 3 to 4
(soaked in solution of your choice)
2.
Make a bar graph of the percent changes. a.
Label axes (x-axis is manipulated variable and y-axis is responding) b.
Place a scale on the vertical axis and give the graph a title. Place the data for both bears on the same graph. USE GRAPH PAPER. c.
If you have a negative value for a percent change, start the vertical axis at a negative number. (For example: -50, -25, 0, 25, 50, 75, 100, etc.)
Error Analysis

Include any important factors that may have affected your results

Discuss how these factors impacted the final results

Suggest ways of preventing these sources of error in the future

CONCLUSION
This section should be thorough, but concise, and should respond to the Testable Question. It should be written in paragraph form .

Restate the testable question and your original hypothesis

Summarize the results obtained in your analysis
 Accept / reject hypothesis based on data

Use data to write the specific reason that you are accepting or rejecting your hypothesis

What is the relationship between the manipulated and responding variables?

Explain WHAT happened to each Gummy bear in each solution, using data.

Include a trend

Include the high and low values for your RV

Explain WHY you got those results, using the concept of diffusion, hypertonic, hypotonic and isotonic solutions.

What is the significance of the results?

Discuss the results and explain and/or analyze with relationship to real-world application and ramifications

Present a new question(s) that emerged from your investigation