And for my next trick, I will attempt to move this red liquid through a glass tube using nothing but my hand!
(For about 22 seconds nothing really happens, but be patient!*)
Here’s the secret: The heat from my hand increased the temperature of the liquid just enough to create an increase of air pressure in the container; that increased air pressure is what pushes the liquid up through the tube. When the liquid is at the top of the container, air is then forced up the tube and cause the liquid to bubble. As the liquid cools so does the air pressure, causing the liquid to fall back down the tube.
And that’s the magic of Charles’s Law**!
*song in the video by Cherub
**the volume of a gas, at a constant pressure, expands as the temperature increases