HOMEMADE ThERMOMETER

A homemade thermometer can be created from simple household materials and provides a reliable and accurate indication of changes in an environment's temperature. Heat and cold will affect the liquid in the homemade thermometer the same way temperature affects a thermometer filled with mercury. As the temperature around your homemade thermometer rises, so will the liquid inside. As the temperature drops, the liquid will drop as well.

Things You'll Need

• Clear plastic bottle
• Tap water
• Rubbing alcohol
• Clear drinking straw
• Red food coloring
• Modeling clay
• Permanent marker
• Traditional thermometer or thermostat

Instructions

1. • 1
     Fill 1/4 of the bottle with room-temperature tap water.
   • 2
     Pour rubbing alcohol into the bottle until it is half full.
   • 3
     Add a few drops of red food coloring to resemble mercury.
   • 4
     Place a small amount of modeling clay on one end of the straw, and put the other end of the straw in the bottle. Position the straw so that it does not touch the bottom of the bottle and affix the clay to the top of the bottle to hold the straw in place.
   • 5
     Put the bottle inside a container with hot water.
   • 6
     Observe how far up the straw the liquid has risen. If desired, use a permanent marker to draw a line on the bottle to indicate the current temperature. The exact temperature can be determined with a traditional thermometer or thermostat, then written on the bottle.
   • 7
     Now place tha bottle inside a container with cold water. The liquid will then contract and flow back down the straw to the bottom of the bottle.

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