Gummy Bear Lab PURPOSE: To demonstrate homeostasis in a cell by investigating how water moves through a gummy bear. MATERIALS: for pairs of students 1) 2 Gummy Bears 2) 2– 50 or 100 ml. Beakers 3) Masking tape 4) Permanent marker 5) Plastic forks 6) Waxed paper or paper plates 7) Distilled Water 8) Saturated Salt Solution 9) Centimeter Rulers 10) Triple Beam Balance PROCEDURE: DAY 1: 1. Obtain two beakers, two Gummy Bears and a ruler. 2. Label one beaker with “Distilled water” and one with “Salt Water” 5. Measure your bear (in cm) from top to bottom (length) and from side to side (width) and from front to back (height). 6. Record the dimensions in centimeters in the data table (Day 1 Initial). 7. Calculate the volumes for the two bears (L × W × H). 8. Find the mass of each bear. Record the mass in the data table in grams. 9. Place one bear in each beaker. 10. Cover one with distilled water and then cover the other with the saturated salt water. The bears should be completely covered. 11. Place the beakers on the counter away from direct sunlight and let them sit overnight. 12. Have the students then predict what with happened to the two gummy bears overnight. © Copyright 2014 – all rights reserved www.cpalms.org DAY 2: 1. The next lab day, gently pour the water over a screen into a sink. 2. Catch each bear using the screen. Place on paper towel or waxed paper. 3. Measure the length, width, and height. Record in the data tables (Day 2 Final). Blot dry by placing bear on a paper towel. 4. BE CAREFUL not to break the bears, they are very fragile. 5. Find the mass of wax paper. Then place the dried bear on the paper and carefully find the mass of the bears. Record in the data tables. 6. Record the difference in the length, width, height and mass of each bear. 7. Calculate the volumes (L × W × H). 8. Complete the conclusion questions. © Copyright 2014 – all rights reserved www.cpalms.org LAB SHEET PREDICITION: Describe what you think will happen to the gummy bear placed in distilled water and the gummy bear placed in salt water: 1) Distilled Water Prediction:________________________________________________ 2) Salt Water Prediction:____________________________________________________ DATA TABLES: SALT WATER DAY Length Width Height Volume Mass 1 – Initial 2 - Final Amount of Change DISTILLED WATER DAY Length Width Height Volume Mass 1 – Initial 2 - Final Amount of Change CONCLUSION QUESTIONS: 1. Were your predictions about the gummy bears correct or incorrect? Why or why not? 2. What happened to the bears placed in distilled water? Why? Be sure to use your data to help explain the result. 3. What happened to the bears placed in salt water? Why? Be sure to use your data to help explain the result. 4. What do you think would have happen to the bear from the salt solution if, they were again placed in distilled water? Why? 5. Explain how this activity relates to homeostasis for the cell. © Copyright 2014 – all rights reserved www.cpalms.org ANSWER SHEET FOR CONCLUSION QUESTIONS: 1. Dependent on student predictions. 2. The gummy bears in the distilled water should increase in length, width, height, volume and mass. The highest concentration of water is outside the gummy bear and so the water will diffuse into the gummy bear causing the gummy bear to increase in size and mass. Make sure the students use their data to support their answers. 3. The gummy bears in the salt water should decrease in length, width, height, volume and mass. The highest concentration of water is inside the gummy bear and so the water will diffuse out of the gummy bear into the cup, causing the gummy bear to decrease in size and mass. Make sure the students use their data to support their answers. 4. If the bear from the salt solution is placed into distilled water, the size and mass of the bear will increase since the water will diffuse from the cup into the gummy bear. 5. Homeostasis is the maintenance of the internal environment of a cell. Water and nutrients will diffuse inside the cell and waste will diffuse out in order for the cell to maintain a stable internal environment. © Copyright 2014 – all rights reserved www.cpalms.org