Ever since I can remember I have had a ridiculously exaggerated fear of tornados. I credit it to living the first 2 years of my life in Kansas, but my mom credits it to the annual viewing of the Wizard of Oz (I grew up in the 80’s before real cable, and the networks aired it once a year. I got to stay up late to watch it). Either way, I am irrationally terrified of tornadoes, and I don’t want to pass this phobia on to my children. As a scientist, I do know (intellectually at least) that the odds of an F5 tornado leveling my house or tossing my car across the interstate are fairly slim. But every time the Emergency Alert Service beeps on my phone or the clouds look a little dark and swirly, my stomach drops and I get a little twitchy around the eyes.
The only thing that has ever helped me is to learn all I could about weather. So here it is, the “whys” of tornados! In this set of activities, kids will make a tabletop tornado and demonstrate the power of air pressure. These are best for kids over 3 (my 3-1/2-yr-old thought everything was really cool), though the tornado tube will provide some entertainment for tiny scientists as well!
LEARN SCIENCE VOCABULARY:
Tornado – a destructive spinning funnel-shaped wind storm that usually accompanies supercell thunderstorms. They are most common in the midwestern part of the United States, but also occur on every continent besides Antarctica (according to the Weather Channel, Argentina and Bangladesh report the most tornados annually after the U.S.).
Vortex – a whirling funnel shape of water or air (like a tornado or water spout).
Air Pressure – air pushing against any object with an amount of force. Even though we usually can’t see air, it is still pushing against us all the time! In fact our bodies are made to stay together in the ambient air pressure on Earth (14.7 pounds per square inch or psi). If there were no air (and therefore no air pressure, like out in space) our bodies would essentially explode! If there is too much pressure (like in very deep water) our lungs and blood vessels would collapse!
MAKE A TABLETOP TORNADO
- Two 2-liter bottles with caps (I used 1-liter bottles, because we go through a lot of tonic water at our house, and it worked just as well.)
- Drill (Adult use only, of course!)
- Duct tape
- Glitter (optional, for effect…and sparkle)
HOW TO MAKE IT:
- Drill a hole in each bottle cap (please have an adult do this and be really careful. And wear gloves!) and then tape the caps together.
- Fill one bottle with water (and glitter if you like).
- Screw on the cap and attach the other bottle to the other side of the cap contraption. (I also applied extra Duct Tape around the caps to secure it. Without it, the caps started leaking when I twisted them too hard.)
- Turn it over and swirl the bottle vigorously to form the VORTEX of water (the “TORNADO” inside the bottle)!
THE SCIENCE BEHIND IT:
The funnel shape, or VORTEX, you see is the water spinning around an upward moving column of air in the center, which is basically the ‘eye’ of the TORNADO. The air is coming up from the bottom bottle, as it is being displaced by the water moving down. If you don’t swirl it fast enough, you will hear the “glug glug” sound of the alternating air going up and water falling down through the small opening between in the caps.
AIR PRESSURE DEMONSTRATIONS
AIR PRESSURE is the reason for the destruction caused by a TORNADO! Super fast-moving air inside a TORNADO creates low pressure which can pull houses apart and lift trees from the ground (think suction inside a vacuum, although true scientists will argue that ‘science doesn’t suck.’ But, hey…we’re teaching preschoolers here!). These 2 classic science demos show how air pushes on things even though we can’t see it!
- THE ‘DRY PAPER’ DEMONSTRATION
- You need a small clear cup or glass, a larger clear container of water and a crumpled piece of paper (or paper towel).
- Ask your kid, “Hey, do you think we can put this paper under water without getting it wet?” (They will either vehemently agree or disagree depending on their contrary attitude of the day, you know how toddlers are…)
- Have them put the crumpled paper inside the small glass and then turn it upside down and push it into the water inside the larger container.
- When they lift it up, they will see that they paper remained dry!
- WHY? There was air inside the small glass that took up space and pushed down on the water as you dropped the glass inside the large container. The AIR PRESSURE prevented the water from coming up inside the cup to get the paper wet!
2. THE ‘FLOATING’ CARD DEMONSTRATION (my son thought this was so cool!)
- Fill up a small glass with water all the way to the brim.
- Put a playing card or similar sized card (preferably with a plastic-like coating so it doesn’t fall apart when it touches the water. I used a Pampers coupon) on top of the the water glass and push it down to seal it.
- Carefully turn the glass and card upside down (you will need to hold onto the card while turning it). Best to do this outside or over a sink in case it goes wrong!
- The card will stick to the bottom of the glass and hold the water inside!
- WHY? The ambient AIR PRESSURE in the room (14.7 psi) is pushing up on the bottom of the card. This pressure is strong enough to counteract gravity pulling down on the water and holds the card in place! (There is also surface tension of the water at work here…the water molecules ‘stick’ to each other, helping to hold the card in place.)