How to Make a DIY Hydrometer

A hydrometer is an instrument used for measuring the relative density of liquids based on the concept of buoyancy.
Materials Needed to Build a DIY Hydrometer:
- 1 plastic straw
- 1 permanent marker
- 1 pair of scissors
- 1 lighter OR matches*
- 1 measuring tape OR ruler
- 1 water glass (the thinner and taller the better)
- 1 candle
- table salt
- metal nails (or other metal objects thin enough to fit into a straw)
*NOTE: Parental advisory is suggested for use of any object able to start an open flame. Please use caution.