Electrolytes, Acid-Base Disorders
Unit 7
Be sure to include photographs of all your experiments and if you work
with a partner be sure everyone’s name is included on the lab!
I. Gummy Bear Experiment
Incredible Growing Gummy Bears
1. Measure and weigh gummy bears before starting. Use a data table to record your
changes.
2. Fill 3 glasses with water.
3. Leave one glass alone and add about a tablespoon of salt to one and a tablespoon of
sugar to the third.
4. Add a few gummy bears to each glass.
5. Wait about 12 hours, measure and weigh the bears.
6. Check back after 24 hours, measure and weigh the bears.
7. Check back after 48 hours, measure and weigh the bears.
How Does it Work?
Why do the gummy bears grow instead of dissolve in the water?
Most sugary candies dissolve when added to water after a few minutes (not a pretty sight!)
Gelatin – one of the main ingredients in gummy bears – is the key.
When gummy bears are made, gelatin and water are heated, just like making Jell-O. As the
mixture cools, the water is drawn out of the bears and they harden to a chewy little bear.
Gelatin is a long chain-like molecule that twists and forms a solid form. As the water is removed
in the cooling process, the gelatin solidifies.
A solute is the dissolved material within another material. So, the gummy bear is the solute in
the water. The water is the solvent. When adding salt to water, the salt is the solute and the
water is the solvent.
When the gummy bears are added to water, the water molecules will move into the bear by
means of osmosis. Osmosis is the movement of solvent molecules (water) through a partially
, permeable membrane into an area of higher solute (gummy bear/gelatin) to equalize the solute
concentration on both sides.
So, what does that mean? There is less water and more gelatin inside the gummy bear. There is
more water outside the gummy bear. The water doesn't want to be crowded, so some of the
water molecules will move inside the gummy bear where there are fewer water molecules and
a lot of gelatin molecules.
The gummy bears started out with a lot of water but when they cooled and hardened, most of
the water was removed.
Why does salt dissolve in water and gelatin doesn't?
Salt cannot form chains like gelatin. The gelatin molecules are much larger than the salt. The
gelatin makes the gummy bear act more like a sponge, absorbing the water instead of
dissolving in it.
What happens when you add salt to the water?
The salt ions are much smaller than the gelatin molecules in the water. The salt water has about
10-20 times the molecules that is in the gummy bear. Through osmosis, the water molecules
are going to move to the area with more solute or molecules in it to even out the number of
water molecules in both the salt water and inside the gummy bear. The water will leave the
gummy bear and move to where there are more salt molecules. The gummy bear won't shrink,
so it looks like it stays the same size.
Adding extra sugar to water will cause the same effect as the salt.
Test this yourself
A. What happens to the gummy bears when you use tap
water vs. distilled water? Will you get different results by
using a different solvent instead of water? What about soda?
Safety note – do not eat the gummy bears after they have sat in the water. When you touch
them with your fingers and drop them in the water, something else is added to the water and
begins to grow – bacteria.
© Copyright 2015 Steve Spangler Science.
http://www.stevespanglerscience.com/lab/experiments/candy-chemistry-experiments/
Unit 7
Be sure to include photographs of all your experiments and if you work
with a partner be sure everyone’s name is included on the lab!
I. Gummy Bear Experiment
Incredible Growing Gummy Bears
1. Measure and weigh gummy bears before starting. Use a data table to record your
changes.
2. Fill 3 glasses with water.
3. Leave one glass alone and add about a tablespoon of salt to one and a tablespoon of
sugar to the third.
4. Add a few gummy bears to each glass.
5. Wait about 12 hours, measure and weigh the bears.
6. Check back after 24 hours, measure and weigh the bears.
7. Check back after 48 hours, measure and weigh the bears.
How Does it Work?
Why do the gummy bears grow instead of dissolve in the water?
Most sugary candies dissolve when added to water after a few minutes (not a pretty sight!)
Gelatin – one of the main ingredients in gummy bears – is the key.
When gummy bears are made, gelatin and water are heated, just like making Jell-O. As the
mixture cools, the water is drawn out of the bears and they harden to a chewy little bear.
Gelatin is a long chain-like molecule that twists and forms a solid form. As the water is removed
in the cooling process, the gelatin solidifies.
A solute is the dissolved material within another material. So, the gummy bear is the solute in
the water. The water is the solvent. When adding salt to water, the salt is the solute and the
water is the solvent.
When the gummy bears are added to water, the water molecules will move into the bear by
means of osmosis. Osmosis is the movement of solvent molecules (water) through a partially
, permeable membrane into an area of higher solute (gummy bear/gelatin) to equalize the solute
concentration on both sides.
So, what does that mean? There is less water and more gelatin inside the gummy bear. There is
more water outside the gummy bear. The water doesn't want to be crowded, so some of the
water molecules will move inside the gummy bear where there are fewer water molecules and
a lot of gelatin molecules.
The gummy bears started out with a lot of water but when they cooled and hardened, most of
the water was removed.
Why does salt dissolve in water and gelatin doesn't?
Salt cannot form chains like gelatin. The gelatin molecules are much larger than the salt. The
gelatin makes the gummy bear act more like a sponge, absorbing the water instead of
dissolving in it.
What happens when you add salt to the water?
The salt ions are much smaller than the gelatin molecules in the water. The salt water has about
10-20 times the molecules that is in the gummy bear. Through osmosis, the water molecules
are going to move to the area with more solute or molecules in it to even out the number of
water molecules in both the salt water and inside the gummy bear. The water will leave the
gummy bear and move to where there are more salt molecules. The gummy bear won't shrink,
so it looks like it stays the same size.
Adding extra sugar to water will cause the same effect as the salt.
Test this yourself
A. What happens to the gummy bears when you use tap
water vs. distilled water? Will you get different results by
using a different solvent instead of water? What about soda?
Safety note – do not eat the gummy bears after they have sat in the water. When you touch
them with your fingers and drop them in the water, something else is added to the water and
begins to grow – bacteria.
© Copyright 2015 Steve Spangler Science.
http://www.stevespanglerscience.com/lab/experiments/candy-chemistry-experiments/
