Jelly Marbles

Materials:
Jelly Marbles(polymers)
Water
Test Tube or Cup
Food Coloring or Color Tablets, optional

Directions:
Place the jelly marbles into the water and watch them grow. It takes a whole day for them to fully expand.

We put the marbles into the test tube in the morning and the children carried the closed tubes around all day checking out the progress. (If using test tubes, the marbles will get stuck in the tube meaning you have to break them to get them out. This was very disappointing for the children. Next time I will remove the marbles before they are full size.) We tried this experiment on a second day in a cup and throughout the day their fingers were in the water trying to feel how big the marbles had become. They have been checking on their shrinking marbles for the past week. This experiment was a HUGE hit for the children.

Variations:
Place a few marbles in a cup and a few marbles in a test tube. Will one set grow larger when water is added?
Will the marbles grow in a sphere form or will they expand in different ways?
Will the marbles absorb the coloring from the water or just the water?
What will happen if you dump the water off the marbles?
When the marbles shrink, will they keep their new coloring?