|MadSci Network: Chemistry|
I would say that bubblegum is both plastic and elastic, since plasticity relates to the ability of something to deform without breaking and elasticity relates to the ability of something to stretch and return to its original shape or dimensions.
To test "stretchiness", I would define it conveniently as the distance a piece of bubble gum would stretch before it broke into 2 pieces.
I would suggest collecting your information at the fair to make it interactive, allowing your visitors to give you the information you need.
In order to test the effects of sugar and sugar subsitutes, choose one brand of gum with high sugar and another that is sugar free. Weigh out gum pieces so that you are giving equivalent amounts to attendees of the fair.
Ask people to be in one of 8 groups (at least 2 people per group):
1.sugary gum, 1 min of chewing,low temperature 2.sugar free gum, 1 min of chewing, low temperature 3.sugary gum, 5 min of chewing, low temperature 4.sugar free gum, 5 min of chewing,low temperature 5.sugary gum, 1 min of chewing,high temperature 6.sugar free gum, 1 min of chewing, high temperature 7.sugary gum, 5 min of chewing, high temperature 8.sugar free gum, 5 min of chewing,high temperatureSupplies you'll need:
Give out gum to volunteers and make sure they know their group (1,2,3,etc.). Tell them to chew their gum for the given amount of time (They can time themselves using your clock).
The low temperature group will take the gum out of their mouths and roll it into a cylinder of a given diameter (use small ruler), then they'll drop the cylinder into ice water for 30 seconds. After that, they'll pull out the cylinder and, holding onto it with both hands, stretch it over top of the yardstick to see how far it goes before it snaps.
The high temperature group will do the same as the low temp group, but will not drop their gum into ice water.
Your job will be to record the results as the people give them to you. At the end you will have finished your experiment with everyone's help.
I hope this suggested experiment is helpful.
Try the links in the MadSci Library for more information on Chemistry.