• Using a funnel, pour equal parts of rubbing alcohol and water into the empty clear bottle
• Add a few drops of food coloring and swirl to mix in
• Place the straw into the bottle, hovering it right at the surface of the liquid
• Use the play-dough to hold the straw in place and form a tight seal around the straw and over the top of the bottle

Experimenting

• Hold the bottle in your hands. Ask, why did the liquid rise? The temperature around the bottle will go up from the warmth of your hands. Try rubbing hands together to get them nice and warm, and try again.

  Grab a bowl of hot water, and hold the thermometer in the hot water. Watch as the colored liquid rises through the straw. Add ice cubes to the bowl, and watch the liquid slowly drop back down. Why is that?

  Place the bottle outside in the sun and see how long it takes for the liquid to rise. Mark the bottle with a marker. Come back at sunset and set it in the same place. See if the liquid increases as much at a colder temperature. Check each day and compare the markings. Is the temperature cooler or warmer than the last time I checked?