Cloud in a Bottle (5/6/15)
- Empty plastic soda bottle
- Rubbing Alcohol
- Duct tape
- Foot pump
- Sharp pencil
- Safety glasses
- Adult supervision
- Put on your super cool safety glasses!
- Pour a tiny amount of rubbing alcohol in the bottle, just enough to cover the bottom.
- Swirl the rubbing alcohol around to coat the sides of the bottle, and securely seal the bottle opening with duct tape.
- Poke a small hole in the duct tape, just big enough to fit the foot pump in the opening.
- While tightly holding onto the cap and bottle, slowly pump air into the bottle. 15-20 pumps should do the trick!
- When you are ready, remove the pump and check out the instant cloud!
HOW DOES IT WORK?
Even though we can’t see them, water molecules are floating in the air all around us. These invisible water molecules are called water vapor. When water molecules are moving around in the air, they normally don’t stick together.
When we pump air into the bottle, it forces the molecules to squeeze together tightly or compress. When we release the pressure, the air expands, which makes the temperature of the air cool down. This cooling process allows the molecules to stick together – or condense – more easily, forming tiny droplets. Clouds are nothing more than groups of miniature water droplets!
Rubbing alcohol forms a more visible cloud than water, because alcohol evaporates more quickly than water. Since there are more evaporated alcohol molecules in the bottle, there are also more molecules able to condense. This is why you can see an alcohol cloud more clearly than a water cloud.
- Two empty plastic soda bottles
- Metal washer
- Lots of duct tape
- Fill up one of the bottles 2/3 full with water.
- Place the metal washer on top, and place the other bottle upside-down on top of the washer so it looks like an hourglass. This will help prevent any leaking.
- Wrap duct tape around the bottle openings to create a good seal. Don’t be afraid to get a little crazy with the duct tape!
- Flip your tornado maker upside-down, give it a swirl, and watch a twister form!
HOW DOES IT WORK?
Even though one of the bottles may appear empty, it is actually filled with air. Since air takes up space, the water can’t flow into the other bottle unless the air has somewhere to go. The trick is to get the water to move out of the way of the hole in the bottle so that the air can go up, and the water can fall down.
Swirling the water around in the bottle creates a vortex. If you’ve ever watched water drain from the bathtub, then you’ve seen a vortex! A vortex happens when a rotating liquid falls through an opening, and gravity pulls the liquid through the opening. The vortex makes it easier for air to come into the bottle and allows the water to pour out faster.
NOW TRY THIS!
Try adding food coloring, glitter, oil, small objects, or anything else you can think of!