Ben Williams

2-16-12

Mr. Emmi

7th Hour

Gummy Bear Lab

Gummy Bear in tap water / Length / Width / Height / Volume
Before Water / 1cm / 1cm / 2cm / 2cm cubed
After Water / 1.75cm / 1.75cm / 3.5cm / 10.72cm cubed
After Salt Water / 0.5cm / 1cm / 1.5cm / 0.75cm cubed
Gummy Bear in Distilled Water
/ Length / Width / Height / Volume
Before Water / 1cm / 1cm / 2cm / 2cm cubed
After Water / 2cm / 1.5cm / 4cm / 12cm cubed
After Salt Water / 0.5cm / 0.5cm / 2cm / 0.5cm cubed

A.  When the bear was put into the distilled water, it grew significantly, and ended up larger than the Tap Water bear. This is because a type of diffusion called “osmosis” happens commonly when water makes contact with a permeable membrane and one side of this membrane contains less water than the other. Osmosis forces the water level to balance out by moving through the membrane. Since distilled water is pure water with no impurities, more water can fill into the bear than plain Tap Water.

B.  When the bear was placed into Tap Water, it followed almost the exact process that the distilled water bear followed, except that the tap water contains more impurities, causing less water to flow in. Again, osmosis takes effect and the bear fills with water, but this time, impurities as well. These impurities fill space that could be filled with water, so less water exists in the bear.

C.  When the bears, both tap water as well as the distilled water, were submerged in salt water, they both significantly shrank. This may be caused by the fact that salt immediately tries to bond with water, explaining the change in water level and the ring of salt where the water used to be. The salt first went to a large source of water, being the bear, and taking the water from it, giving it it’s new small size.

D.  If these small bears were now, after being submerged in salt water, to be put into distilled water for 24 hours more, I predict then would grow to be a fairly large size again. This is because they are now in a more water filled environment, and would absorb this water to a size between their original size and the size they assumed when they were put in the distilled water previously.

Bears / % Change in Water / % Change in Salt Water
Tap Water Bear / 525% Increase / 93% Decrease
Distilled Water Bear / 600% / 95.83% Decrease

In our Gummy Bear experiment, we have concluded that gummy bears have a permeable membrane out side of it, allowing water to freely flow in and out, also known as the process of diffusion or osmosis. We have also discovered that the bear grows significantly more in distilled water, which is free of impurities, than tap water, which includes impurities. This does cause a higher percent of shrinkage when put in the salt water, because they shrink to close to the same final size. Osmosis takes place in all of these portions, whether it is filling the bear with water, or removing it to cover for the amount of saturated water existing around it. If we were to put the bears into distilled water now, I hypothesize that they would expand to a volume of some where in between the original volume and the volume it had after 24 hours of sitting in distilled water. Overall, we see that the bear has wide capabilities of expanding from large to small as shown in the graph and in the charts, and that the bears have a very permeable membrane that water easily passes through.