Thermometer Experiment

Supplies:

Plastic or glass bottle Straw (clear plastic/silicon is best) Food coloring Modeling clay Water Rubbing alcohol

Directions:

1. Place a drop of food coloring into your bottle and fill it about 1/4 of the way with water and 1/4 of the way with rubbing alcohol. Close tightly and shake to mix the food coloring, water, and rubbing alcohol evenly. Open the bottle once everything is thoroughly mixed.

2. Hold the straw in the middle of the bottle opening so that it sits in the liquid about 1 inch from the bottom.

3. Fill in the bottle opening around the straw with the modeling clay to hold it in place. This should create a seal around the straw. Be careful to leave the straw open to the air.

4. Try moving your thermometer to different places inside and outside your home to see the liquid rise and fall in the straw.

Try this:

What happens if you make your thermometer with just water? It should respond to temperature changes a lot slower or less. Rubbing alcohol has a much lower boiling temperature so heat can transfer a lot faster.

What’s happening:

As the temperature rises, the water and rubbing alcohol in the bottle will expand and rise into the straw. The hotter it gets, the higher up the liquid should rise. As it gets colder, the liquid will contract which should make the level of liquid in the straw drop.