Magic thermometer

Materials:

-Bottle (50cl.), water, alcohol (96º), food coloring, straw and putty (play-doh).

Instructions:

-Combine the alcohol with water (same quantity, 1/1) and food coloring. Mix it.

-Make a hole in the bottle’s cap.

-Put the straw trough the hole.

-Seal the hole with putty.

-Leave it in a sunny place.

Why does it work?

It works because when an object gets hot, usually gets bigger.