Science Buddies: "Ask an Expert"

i am doing a project on "Does chemical LIghtening Affect the Structure of Human Hair?". One of the materials i was confused about was the glue- hot glue or regular glue? WHAT KIND OF GLUE? I dont know if using hot glue would heat the human hair strand and affect it to lose strength or something, but I wasn't sure.
Specifically, i am testing the strength of a untreated swatch of hair, a swatch of hair lightened for fifteen min., and a swatch of hair lightened for 30 min. When i test the strength, would it be unwise to test 3 strands at once using your penny-in-a-cup method? Should i worry that one of the three hairs might break before the other two?

Hello and welcome to the forums!

Any kind of glue should work. Hot glue will be quicker for you. White glue may be a problem if you test the hygrometer in a very humid environment for long periods of time, as it is water soluble.

For the penny in a cup method, I would recommend testing one hair strand at a time. To get the best results, as the experiment says: "Test at least 10 separate untreated strands and at least 10 separate treated strands." Lots of tests of each type of hair is good!

Keith