We had a great time at the science party we hosted with Seattle store Satsuma last weekend! A big hit was the tornado in a bottle activity – great for even the smallest kiddos!
With some common household items, this project goes together quickly. Simple and fun!
- Water bottle
- Dish soap
- If water bottle is empty, fill ¾ full with water. If water bottle is full, empty it until ¾ of the water remains.
- Add a few pinches of glitter to the water.
- Add four drops of dish soap.
- Replace water bottle cap.
- Holding the water bottle upside down, move it around in a big circle – this will create a “tornado” inside the water bottle, which is easy to see because of the glitter.
So what causes the tornado in the bottle? There are two things going on. One has to do with how you spin the bottle, and the other has to do with what is inside the bottle.
First, spinning the bottle in a circle creates force that moves the water. Where can it go? So long as you screwed the lid on tight, it can’t leave the bottle. So, the water moves around the edge of the bottle. It is going along a circular path. When something moves along a circular path, it also moves toward the center of the circle. That is called centripetal force.
The second part to understanding how you created a tornado in a bottle is what is in the bottle: water – or a fluid. When you spin a fluid around a central point, it creates a spiral called a vortex. You couldn’t do this experiment if you filled the bottle with gummy bears. (Though, that would be a much tastier experiment.)
If you look around, you can see examples of vortices in lots of places. Some are created by very powerful forces, such as a tornado or a whirlpool. Others are not as chaotic, and you can find them in your home. If you fill a bathtub and open the drain, then a whirlpool is created as the water rushes out. You can even see a vortex when you drop a bit of cream into a cup of hot coffee. The swirls of cream are vortices – and look really pretty, too.
So get your water bottles ready!! The kiddos who did this activity with us loved it, and we hope that you will, too!!