WHAT YOU NEED: 

• Water

• Rubbing alcohol

• Empty water bottle

• Red food coloring

• Clear straw

• Modeling clay

• Permanent marker

WHAT YOU DO: 

• Mix equal parts rubbing alcohol and water in the bottle with 2 drops of red food coloring. You should only fill the bottle about 1/4 full 

• Put the straw in the bottle so it’s in the liquid but doesn’t touch the bottom. Wrap the clay around the straw and the mouth of the bottle to create a seal, but be careful not to cover or pinch the straw. 

• When the liquid has risen in the straw, mark the level and the temperature in the room (check the thermostat in your house). 

• To make your measurements more precise, set the bottle in a bowl of warm water. When the water stops rising in the straw, mark it. Take the temperature of the warm water and write it on the line. Do the same thing with a bowl of cold (not frozen) water.  

WHAT IS HAPPENING:

Since the bottle is air tight, the warmth causes the air to expand and push the water up the straw.  Cold air contracts so the water in the straw drops. 

DISCUSSION IDEAS:

Why is it important to know what the temperature is?