Making a Hygrometer with Strands of Hair

[deleted-306378]

Hi Whoever is reading this!
I really need help with this project. I'm using the original science project from science buddies that IS my subject. SO in this project I am making a hygrometer using a 25x10 cm piece of wood, a few nails and several long strands of hair. So I will briefly try to explain my project. You nail one nail into the top of the board about a cm from the bottom and a cm in from the left side. Then you cut a small triangle of thin plastic (such as plastic from a deli container) and attach the flat long edge of it to the nail before you nail it in. (Sorry that its not in the right order ). Then you glue the hair strands (3) ends to the triangle. Then making a straight up about a cm from the top of the board nail another nail in. Then glue the other ends of the hair to the side of the nail. Then on top of the plastic triangle you tape a dime. After its dry put the whole thing into a sealed box with a wet sponge. In ten minutes the hair is supposed to change shape (shorten) and pull the plastic triangle towards it. But I have tried it and tried it with different temperatures of water and it DOESN'T change! It stays exactly the same. The only problem I can think of is that we could not find a big enough box that would hold the hygrometer so we changed it to 21cm x 10cm. I also tried it without the dime. The problem also might be that there are not enough hair strands since my hair is very thin. (I used my own hair) But I am absolutely one hundred percent sure that I constructed the hygrometer correctly. PLEASE help me!! The science fair is in January but I am determined to win and need as much help as possible!!
Thank you SO much whoever reads this!!
Hannah Loftin
(I am fourteen and in eighth grade and I am NOT a teacher. I don't know why they call me that)

[norman40]

Hello hannahloftin14,

I’m assuming that you are working on the project described here:

https://www.sciencebuddies.org/science- ... p010.shtml

I’m sorry that you’re having trouble making your hygrometer work properly. One possibility is that the thin plastic triangle is fastened to the board too tightly to move freely. If that’s the case, you might try enlarging the hole made by the nail in the plastic triangle so that this piece is free to move when the hair strands pick up moisture. Also, you might try letting your hygrometer sit in the 100% humidity sealed box for more than ten minutes to see if you get a change in hair strand length.

I hope this helps. Please post again if you have more questions.

A. Norman