Kyle Chisholm 2/26/12 Emmi 5th Hour Science Gummy Bear Lab Analysis A. What happened to the bears when placed in distilled water? Why? The bears, when placed in distilled water, grew about four time bigger. This is because of osmosis. The water concentration of the water is greater than that of the gummy bear so osmosis occurs. The substances that make up the gummy bear- glucose, starch, and gelatin- absorb the water instead of the water dissolving the bear. This causes the bear to swell and increase in size. B. What happened to the bears when placed in tap water? Why? The bears, when placed in tap water, grew about 12 times bigger. This happens because of the same reasons of the distilled water, but the bears grew bigger. This is because of the impurities in the tap water. The impurities caused the bears to swell more than the distilled water. C. What happened to the bears when placed in salt water? Why? The bears, when placed in salt water, shrunk to about their original size. The bears grew due to their concentration of water molecules increasing. Salt water, however has a low concentration of water molecules due to it's salt crystals. When the large bears were placed in salt water, osmosis occurred balance the concentrations of water. After osmosis, the water concentration of the gummy bears was much less than it was to start which therefore caused the gummy bears to shrink. D. What do you think would have happened to the bears if, after the last day, they were again placed in distilled water? I think the bears, if again placed in distilled water, would grow roughly as much as they did when they were first placed in distilled water. E. Calculate the percent change in the volume after each step of the experiment. Tap Water Length Width Height Volume Before Water 1.1 cm 1 cm 2 cm 2.2 cm After Water 2.5 cm 2.5 cm 4.5 cm 28.125 cm After Salt Water 0.9 cm 1 cm 1.75 cm 1.575 cm Distilled Water Length Width Height Volume Before Water 1.2 cm 1 cm 2.1 cm 2.52 cm After Water 1.75 cm 2.2 cm 3.25 cm 12.5125 cm After Salt Water 1.5 cm 1.2 cm 2 cm 3.6 cm Bears % Change in Water % Change in salt water Tap Water 1178.41% Increase 94.4% Decrease Distilled Water 396.53% Increase 71.23% Decrease F. Make a bar graph of the percent changes. 1400 1200 1000 800 600 400 200 0 Distilled Water Tap Water -200 G. Write a paragraph which explains the results of this experiment using the concepts of diffusion and swelling. Many important principals of discussion, osmosis, and swelling can be observed from the gummy bear lab. The reason osmosis first occurred is because of the concentrations of water. There was a very low concentration of water in gummy bears so when the bears were placed in water the water molecules moved from the higher concentrated area, or the water, to the lower concentrated area, or the bears. This happened until the water molecules were balanced on each side. The water was absorbed due to some of the ingredients that makes up the bears. Without these ingredients, the water would have dissolved the bears. The swelling occurred in proportion to the water concentration and ended when osmosis finished. While the bear in distilled water grew 396.53% times bigger, the bear in tap water grew 1,178.41% more than it's original size. The tap water had impurities which caused t7he bear to swell larger than the distilled water bear.