Rain Cloud In A Jar Experiment
- Adult supervision recommended.Take the cup and cut small slits or pierce small holes in the bottom of the cup and around the bottom half of the cup. (I used a sewing needle to make the holes.)
- Place the cup into the empty jar top. It should not touch the bottom of the jar so that you will be able to see the rain from your rain cloud.
- Drop the cotton balls into the cup (not the jar) and push them down to the bottom of the cup. If you don’t have cotton balls, ball up a paper towel or tissues into the bottom of the cup.
- Add 2-3 drops of blue food coloring to ½ cup to ¾ cup of water. The water amount varies to the size of the cup you are using. You’ll see why as we start the experiment.
- Using the eyedropper, drip the blue water into the cup (not the jar) a dropperful at a time. This will take time, so be patient. Notice the darker color the “cloud” cotton balls are turning as they fill with the water. What happened? How much water did it take before you finally saw the rain come out of your rain cloud? You may have to make more water to finish the experiment.
- Take your fingers and press down on the clouds full of rain. What happens to the rain? Is there more rain, or less? Does it drip faster or slower? What happened after all the rain was squeezed out of the clouds? Did the cloud color lighten?
The Science Behind the Experiment
In this experiment, the cotton balls are the clouds, the water is the water droplets. As you add the water to the clouds, the clouds absorb the water. When the clouds have absorbed beyond their capacity (saturation point), then the rain will fall out of the holes of the cup due to gravity pulling the water to the earth.
What Is A Rain Cloud?
What Is A Rain Cloud? Clouds are formed when water vapor rises into the air and attaches to tiny particles of dust forming water droplets. When billions of these droplets come together, a visible cloud forms. Over time, these droplets and/or crystals attract more water droplets from around them making the cloud larger and darker in color. When the cloud has too many droplets and the droplets grow heavy, gravity pulls them downward towards the ground forming rain.
What Is Snow and Sleet?
Just as the rain falling in the above explanation, snow occurs when the atmosphere is freezing cold (32 degrees) all the way from the clouds to the surface of the earth. Sometimes the ground temperature is warmer than the cloud area, which is why sometimes snow turns to rain before hitting the ground. If that rain begins to refreeze before hitting the ground, then sleet is formed.
What Is Hail?
Unlike snow and sleet, hail occurs during warm temperatures. Hail is a chunk of ice that forms from supercooled raindrops that gather in updrafts during warm temperature thunderstorms. The updraft gathers more and more of these frozen raindrops and will eventually fall to the ground because of gravity. The size of the hail is directly based upon the strength of the storm and has been reported as large as the size of a softball.
Tornado In A Jar Experiment
- Fill the jar about ¾ full of water. The water temperature doesn’t matter.
- Add 2-3 drops of the food coloring. This depends on how dark you want the water to be.
- Add a few drops of Liquid Dish soap.
- Add a teaspoon of vinegar (lighter color if possible)
- Add a teaspoon of glitter.
- Place lid on tight to keep from leaking. You are going to hold the jar by the top so make sure it’ssealed tightly.
- Holding jar from the top securely with your hand, begin to swirl the jar in a smooth steady motion until you see the vortex form in the water.
- If you are having trouble seeing the tornado, after swirling, place in front of a white paper or light-colored background. It will be easier to see.
The Science Behind the Experiment
Adding the soap to the water created the bubbles that will allow you to see the tornado, to keep the bubbles to a minimum, the vinegar was added. The food coloring colors the water so that the inner tornado will be easier to see.
When you spin the water in the jar, it creates a vortex (funnel) in the center. As the water spins, centripetal force, causes the water to spin around that vortex making a mini tornado. The glitter allows you to see how objects can be pulled into the vortex during a true tornado. If you had other small, light objects in the jar they would spin as well in the vortex. Try it! But make sure that the lid is secure before spinning! Have fun!
What Is A Tornado?
Tornadoes begin with storms. Storms create condensation (rain or sleet) and that creates heat on the ground. That heat creates upward drafts of air back into the clouds. The stronger the storm is, the more drafts are created moving up into the air. As the drafts move up, they begin to change directions, absorbs the moisture in the air and continues climbing into the sky. This creates a long tube of air between the drafts which becomes a “mesocyclone”. The dry air circles around the back of the cyclone creating a draft moving back down to the earth. This funnel of air will have different temperatures of air inside the cyclone and outside of the cyclone. The mesocyclone will then start to draw in the parent cloud to grow. As it grows and picks up speed the bottom of the funnel(mesocyclone) will stretch downward and continue to gather speed. Once it touches the ground, it is then referred to as a tornado. Most tornadoes are very short lived, however, some can last an hour and have speeds up to 200mph. When the moisture in the air dries or the temperature differences return to normal in and out of the funnel, then the tornado will lose momentum and return to the parent cloud.
- Did you make a cloud in a jar? What happened when you or Ms. Crystal added more cotton balls and pressed down? Can you remember what she called that?
- What is the water cycle? Maybe you would like to draw a picture instead of writing about it. If you feel like sharing, we love to see pictures at STEAMfest.
- Ms. Crystal created a tornado in a jar with water and formed a “vortex” or funnel. Where else might you see a vortex of water like a tornado? Hint – Close the drain in a sink or tub, add a couple of inches of water, and release the drain. Did you see the water spinning in a vortex like you saw in your jar?
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