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In this month’s STEAM Experiment for Kids, we’re reusing the empty soda bottles from the Soda Geyser Experiment last month to make a tornado in a bottle!
As you explain this experiment to your kids, it’s a good time to talk to your kids about tornadoes and your tornado safety plan if you live in an area that is prone to tornadoes.
This is one of those sensory bottle activities that provides endless fun for the kids. You’ll be surprised at how long they will want to sit and watch the water swirl around like a tornado and try it over, and over, and over again.
Let’s Talk about the Science
Tornadoes are a fascinating and frightening meteorological phenomenon. Tornadoes are a violently rotating column of air that when mixed with rain droplets appears as a funnel coming from storm clouds. They are the most violent atmospheric storms.
Every year around 1,200 tornadoes are recorded in the United States. That’s why it’s important to have a tornado safety plan in place for your family in case a tornado occurs near you. For more information on tornadoes head to the National Severe Storm Laboratory website.
The “tornado” we see in the bottle in this experiment is really a vortex. The vortex is created when the liquid moves in a circular motion around a counterpoint. Gravity pulls the liquid down while air rises through the center of the vortex.
You can read more about this experiment on Steve Spangler Science.
Tornado in a Bottle Experiment
This is a great activity for kids age 1+. Younger kids will observe and may want to play with the bottles (which is great!), and older kids will be able to create the tornado themselves.
Make sure to have towels on hand in case of spills and leaks to prevent slips and falls. Also, if using food coloring, be sure to protect surfaces and clothing from stains.
- 2 identical plastic bottles (We tested 2L and 16oz – both worked great and the smaller bottles were perfect for little hands)
- Food coloring (optional)
- Duct tape
- Small toys – such as glitter, beads, buttons, toy animals, etc (optional)
- Tornado Tube (optional)
- Explain to your child what is a tornado, and what your tornado safety plan is at your home. Here are some notes on what to say:
“A tornado is a funnel cloud that can form during a severe thunderstorm. It produces high winds and can cause lots of destruction, but they are also very rare. If a tornado warning is issued while we are at home, we will hide together in the pantry. This is our innermost room in the house with no windows.”
2. Fill one bottle almost to the top with water
3. Add a few drops of food coloring to the water
4. Duct tape the empty bottle to the full water bottle (opening to opening)
5. Flip the bottle over (so the bottle with the water is on top), what happens? The water starts to go to the bottom bottle slowly while “glugs” of air come up.
6. Rotate the bottle, so the water is once again in the top bottle, then rotate it in a tight, clockwise circular motion. As you rotate the bottle a tornado should form as the water moves into the lower bottle.
7. Flip the bottles over and try again!
8. Repeat as many times as you like, changing small things to see how they affect the timing and tornado (vortex) formation. Here are some examples of fun variations you can try:
8a) Rotate the bottle in the counterclockwise direction (the opposite direction as your did previously)
8b) Time how long it takes for the water to completely empty from one bottle to the other. Does the vortex make it go faster or slower?
8c) Add dish soap (this will make the vortex more noticeable as it fills with bubbles). Even better – add lamp oil if you have it (this will color only the tornado in the bottle)
8d) Add items to your water bottle (such as glitter, beads, beans, small toy animals, etc…), and observe how they move with the water as the vortex forms. Do they get sucked into the vortex or do they remain in the perimeter of the bottle?
The formation of the vortex makes it easier for the air to enter the top bottle and water to exit into the bottom bottle. The air comes up through the hole in the middle of the vortex and the water pours out around the edges of the bottle opening. If you don’t have a vortex, the air and water have to take turns entering and exiting the bottle making bubbles and moving much slower.
I hope you and your kids enjoyed this simple STEAM experiment. It’s an easy and fun way to introduce STEM to your kids.
The experiment is easy to do with very few materials required, and you don’t need a strong science background to do this and explain it to your kids (just use my notes from the What Happened section above!).
Have you tried this experiment before? If you try it out, let me know how it goes in the comments below.