Hi Jose1,
One of the neat things about silly putty is that its rheological properties change depending on how fast you deform it. In other words, the behavior of silly putty is "strain-rate dependent". For example, if you pull slowly on silly putty, it will act a bit like melted cheese on a pizza--stretch out and form stringers. But, if you pull on silly putty very quickly, it will break instead of flow. The viscosity of silly putty, which is defined as how much stress you apply to the putty divided by how much it deforms per unit time, depends on temperature.
This is a pretty basic, but clear, discussion of silly putty rheology:
http://www-old.me.gatech.edu/jonathan.c ... yputty.pdf
This website provides a more advanced discussion of silly putty's rheology (silicone putty = silly putty):
http://www.geology.um.maine.edu/geodyna ... heory.html
For an overview of what strain rate is, take a look at this Wikipedia article:
http://en.wikipedia.org/wiki/Strain_rate
So, you could look at a couple of different variables. One is strain rate, the other is temperature. Read up on the rheology of silly putty (the links above are a good starting point, but I suggest doing some additional research on your own), and see if you can think of a question you could test about how strain rate or temperature affects the behavior of silly putty. This Science Buddies webpage does an excellent job of explaining how to formulate a good question:
https://www.sciencebuddies.org/science- ... tion.shtml
If you get stuck, feel free to post back. I'll get an email when you reply to this post, so I'll get back to you within a day of when you reply.