Foggy Fun

3.9 based on 10 ratings

Updated on Jan 18, 2013

Grade Level: 6th; Type: Environmental


The goal of this project is to create radiation fog to see how it forms and how environmental elements affect it. Studying fog in a bottle provides opportunities to test hypotheses such as whether light can shine through the thick layer of air.

Research Questions:

  • How does fog form?
  • How does wind affect fog?
  • How does light work in fog?

Fog is a cloud that forms just above the ground. There are two types of fog: advection and radiation. Advection fog occurs on the Pacific coast when warm, moist air blows over cold water, forming a low-hanging cloud that gets blown inland. The heavy, wet cloud provides water for coastal plants. Radiation or ground fog is common everywhere, especially in autumn. A thin layer of warm, moist air forms near the ground, and cooler, dry air lays atop it. As the temperature drops, condensation occurs. Clear nights with a slight breeze offer the optimum conditions for radiation fog.


  • At least two bottles with narrow necks to hold ice cubes
  • Hot and cool water
  • A ruler
  • Additional supplies: food coloring, a fan, etc

Experimental Procedure

  1. Fill one bottle with very hot water.
  2. Fill the other bottle with an inch of cool water.
  3. After several minutes, empty the hot water and replace with one inch of hot water.
  4. Place an ice cube in the neck of each bottle.
  5. Record what happens in each bottle.

Variations include:

  • Add food coloring to the inch of hot water and see if the fog colors.
  • Blow a fan over the fog, increasing the speed to judge the affect of a slight breeze versus a brisk wind.
  • Shine several flashlights through the fog to see what happens when light hits the wet, heavy cloud.

A simple logbook records the effects of creating fog and any conditions applied to it:

Initial Creation of Fog

30 sec. after inserting ice cube, wisps of smoke form just above the water’s surface. It grows until 2:30 when the cloud settles.

Second Test

40 sec. after the ice cube was put in the neck of the bottle, a small cloud formed above the water and grew until 2:45.

Fan on Low Setting

Terms/Concepts: Advection fog; Radiation fog


Jane Frances Healey taught for many years at both the college and high school levels. Currently, she's a freelance writer in the San Francisco area, and she enjoys doing research on a wide variety of topics.

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