We experience quite a bit of thunderstorms here in Arizona, which is a new thing for my kids! They love to stand by the window and watch the lightning and heavy winds and are amazed at the loud thunders.
Do you know that most tornados form from thunderstorms? A tornado is a violently rotating column of air extending from a thunderstorm to the ground.
You don’t want to be anywhere near a tornado when it happens. So we made a tornado in a bottle to demonstrate to the kids what the tornado looks like. It turned out to be one of my kids’ favorite weather experiments!
How to Make Tornado in a Bottle
- Two clear plastic bottles
- Duct tape
- Optional: Crazy glue or hot glue gun
- Optional: Food coloring and glitter
1. Fill one of the plastic bottles about ¾ full of water. Add food coloring and glitter to make the tornado more visible.
2. Place the washer on top of the water-filled bottle. Use crazy glue to secure the washer to the bottle if you wish.
3. Turn the empty bottle upside down and place the opening on top of the washer. Again, use crazy glue to ensure a tight seal.
4. Use duct tape to connect the two bottles together (with the washer in between the openings).
5. Quickly turn the bottle over and set it on the table or ground. Move the top bottle (the one with water) in a circle until a vortex forms. Water will start spiraling into the lower bottle in the form of a tornado!
The kids loved watching the tornado spin round and round in the bottle. They had a little trouble getting it started at first, but after a few tries, they were experts at forming the tornado!
We did start off the experiment on the wrong foot. We used a washer that had a very small opening, and no matter how much we twirled the bottle, we could not get the tornado to form. Since we used crazy glue, we could not separate the bottles from the washer and had to ditch the whole set up. Thankfully, our second try was successful!
Science Behind the Tornado in the Bottle
You might have noticed that when you first turn the bottles over, hardly any water drips from the top to the bottom bottle. Strange, isn’t it? Why doesn’t gravity pull the water down?
When the water is not spinning, the surface tension across the small hole in the washer prevents the water from dripping. You can try the experiment without the washer and observe what happens.
When you twirl the bottle in circles, the water starts rotating and forms a vortex that looks like a tornado. This is due to the centripetal force, or the inward-facing force pulling the water toward the center of its circular path. The hole in the vortex breaks the surface tension and allows air to flow from the lower bottle to the top bottle.
I have lost count of how many times my kids spun the bottle to create the tornado. They can’t get enough of this tornado in a bottle experiment! I don’t blame them, how many times can you say you form one of the deadliest weather phenomenons at home?
My kids also love the rain cloud in a jar experiment, where you can produce colorful rain from a fluffy cloud. Try it out!