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Clouds, lightning, and thunder (for youth)

By Julianna Costanzo and Cailyn Raper, UF/IFAS Extension Sarasota County 4-H Interns 2020 and 2021.

Have you ever wondered how clouds, lightning, and thunder form? All three of these natural phenomena occur in relation to one another. Thunder is produced by lightning, and lightning is produced by clouds. Let’s explore how these three interact and learn how to make our own bottle cloud.

Clouds

clouds

Water droplets, ice crystals, and particulate matter are what make up clouds. [CREDIT: Pero Kalimero on Unsplash]

Clouds are a collection of water droplets, ice crystals, and particulate matter floating together in the air. Matter makes up all of the physical, material stuff in the entire universe! Particulate matter, or aerosols, is a word for tiny pieces of matter floating in the air, like dust, dirt and sea salt.

 

When water evaporates, clouds form. Evaporation is the process in which the water turns from a liquid into a gas and it rises into the air. Water vapor continues to rise high into the sky, where the air is really cold. The cold temperatures cause the gas to turn into water droplets and ice crystals. These water droplets cling to the particulate matter floating in the air. When the water droplets, ice crystals, and particulate matter all come together, a cloud is formed!

Clouds are very important. During the day, clouds protect us from the sun’s harmful rays. At night, clouds insulate the earth by keeping warm air trapped close to earth’s surface, keeping the planet from getting too cold. Sometimes, the amount of ice crystals, water droplets, and particulate matter becomes too heavy to remain floating in the air. When this happens, we receive precipitation through rain, snow, sleet, hail, or mist.

Lightning

Lightning coming out of clouds

[CREDIT: Tsvetoslav Hristov on Unsplash]

Lightning is a giant burst of electricity that happens between a cloud and the ground, or between two areas within a cloud. This burst of electricity is caused by the polarization of charges. Everything around us positive and negative charges: there are charges within you, the water, a table, a soccer ball, the air, the ground, and everything in between!

Polarization

Protons are tiny forms of matter that carry positive charges. Electrons are tiny forms of matter that carry negative charges. There are protons and electrons in everything. When an object has more protons, the object is positively charged. If the object has more electrons, the object is negatively charged. If there is an equal amount of protons and electrons in an object, that object has a neutral charge. Electrical polarization is caused by the separation of charges. That means that one area or object builds up a positive charge, and another area or object close by builds up a negative charge.

Magnets are also polarized, but not with protons and electrons. They are polarized because they are separated into a north pole and a south pole. When we put two sides of two different magnets together and they repel each other, that is because two like poles are coming close together. When two magnets attract each other and snap together, that is because a north pole and a south pole are coming close together. Similar to magnets, like charges repel each other and opposing charges attract each other. To recap:

  • Negative charges repel negative charges
  • Positive charges repel positive charges
  • Negative charges attract positive charges
  • Positive charges attract negative charges
Lightning Formation

Lightning is caused by polarization within the cloud. [CREDIT: Max LaRochelle on Unsplash]

The top of a cloud is very cold. When the ground beneath the cloud is warm, it causes the surrounding air to heat up as well. The warm air then heats the bottom of the cloud. The hot air and cold air within the cloud begin to mix and particles in the cloud start running into each other. This leads to polarization within the cloud. The cloud experiences electrical polarization: the bottom of the cloud builds up a negative charge and the top of the cloud builds up a positive charge.

 

The ground beneath the cloud also builds up a positive charge. When the polarization intensifies, the negative charges rush towards the positive charges at speeds of up to 60 miles per second! Those electrons could travel from Sarasota, Florida to Disney world in less than two seconds! When the opposing charges meet, lightning strikes. Lightning can strike between the positively charged ground and the negatively charged bottom of the cloud, or it can strike between two polarized areas within a cloud.

Light Waves

Light waves are what allow us to see the world around us. [CREDIT: Sebastien Gabriel on Unsplash]

The burst of electricity in the sky creates light waves! Light waves are very small. The length between the top and bottom of the wave is smaller than a grain of sand, so we cannot see the actual wave pattern that light waves create. Light waves are what cause us to see things. These waves travel from sources such as lightning strikes, light bulbs, or the sun, and bounce off of the objects around us. These waves then travel through our eyes to be processed by our brains. When we see a lightning strike, light waves are traveling directly to our eyes. When we are looking at an object in such as a chair, tree, car, or cup of juice, light waves are traveling from their source, reflecting off of that object and then traveling through our eyes.

Thunder

[CREDIT: Dave Hoefler on Unsplash]

Thunder is the sound caused by lightning. When lightning strikes, the air around the lightning strike heats up to temperatures as high as 50,000 degrees Fahrenheit! The air around the strike then cools off very quickly. Hot temperatures cause air to expand. Cool temperatures cause air to contract, or shrink. Just like lightning strikes extremely fast, the heating and cooling of air also happens extremely fast. That means the air around the lightning strike expands and contracts quickly!  This rapid expansion and shrinking of air results in the creation of sound waves. We do not see these sound waves, we hear them! The sound produced by the expansion and contraction of the air is what we call thunder. Lightning and thunder happen at the same time, the reason that we see lightning before we hear thunder is because light waves travel faster than sound waves!

Create a Bottle Cloud

Follow these directions to create a cloud in a bottle!

You will need:

  • a clear glass jar with a lid
  • aerosol hairspray
  • 1 cup of boiling water
  • ice cubes
  • food dye (optional, but it makes the experiment more fun!)

Directions:

  1. Boil the water.
  2. Pour the boiling water into the glass jar until the glass jar is about halfway full.
    1. OPTIONAL: add food dye to the water that is in the jar! This makes it easier to see the difference between the water and the cloud.
  3. Spray hairspray into the glass jar and immediately close the lid.
  4. Place 2-3 ice cubes on top of the jar lid.
  5. Watch the cloud form!

Can you explain why the cloud is forming in the jar?

Additional resources:
  • Youth can get involved with their local 4-H club to explore their interests in science, technology, engineering, math and many more topics. Kids (ages 5-18) can join a club, choose a project and earn pins for exploring their interests and passions. Learn more at our Join 4-H page.
  • To see a demonstration of how hot temperatures cause air to expand and cool temperatures cause air to contract, check out UF/IFAS Sarasota County’s LIFE: Science Shorts – Clouds, Thunder and Lightning!
  • Learn more about weather using the National Oceanic and Atmospheric Administration’s SciJinks website.
  • Check out the Is your 4-H project animal enjoying the weather? blog.

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