ROANOKE COUNTY, Va. (WFXR) — WFXR News’ meteorologist Kara Thompson visited the Icimani Adventure Center for the Dark Hollow Day Camp’s STEAM Day. STEAM stands for “science, technology, engineering, art, and math.”

The young campers ranged from rising third-graders to rising sixth-graders. For their STEAM Day, the scouts learn about the medical field, robotics, engineering, and meteorology.

The girls learn about how weather impacts our lives and how meteorologists do their jobs. They talked about different types of severe weather and how weather radars operate.

One of the activities the scouts took part in was making a “cloud in a jar.” This simple experiment can be completed at home and shows how clouds form.

Making a Cloud in a Jar

Things You’ll Need:

  • A glass jar with a lid or a glass cup with a small plate
  • A can of aerosol hairspray
  • Hot water
  • Ice


  • Fill about 1/4 of the jar with hot water
  • Take the jar lid, flip it upside-down, and fill it with some ice
  • Spritz some hairspray inside the jar
  • Quickly place the upside-down lid on top of the jar. Wait a couple of minutes and you’ll notice a faint cloud forming in the jar
  • After two minutes or so, you can release the cloud by taking the lid off of the jar.

Why Does This Happen?

You need evaporation and condensation in order for clouds to form. Evaporation will cause water vapor to form. As the water vapor rises, the air cools.  The cooler air higher in the atmosphere cannot hold as much water vapor as the warmer air near the surface of the earth.

Some of the water vapor will want to condense in the cooler air. Condensation happens with the help of tiny particles in the air; this can be dust, pollen, smoke, or even salt from the ocean. Those particles provide surfaces on which water vapor can change into liquid droplets or ice crystals. We call these particles cloud condensation nuclei.

In this experiment, the water vapor was created by using warm water in the jar. The hairspray acted as the cloud condensation nuclei.  When you added the ice-filled lid on top, you cooled the warm air. The cold lid causes the water vapor to condense on the surface of the hairspray particles. This helps to form a cloud.