In this science activity for kids, students will discover how a warm air mass (red water) and a cold air mass (blue water) combine to create a thunderstorm.

Conduct this science experiment to create convection currents with students:


  • Blue ice cubes (made by adding a few drops of food coloring to the ice tray before freezing)
  • Red food coloring
  • Plastic container
  • Water


  • Fill the container with water about half way. Wait until the water is still, and then gently add a couple of ice cubes to one side of the bin.
  • Add a few drops of red food coloring to the other side. Be very careful not to disturb the bin of water.
  • Observe the bin.
  • Students will observe a convection occur as the red color rises and the blue coloring sinks to the bottom. Water is flowing from one position to another, and heat is being transferred.

The Science:

The red water represents a warm air mass and the blue water represents a cold air mass. When convection currents occur, the air becomes unstable and a thunderstorm forms. A body of warm air is forced to rise by an approaching cold front forming a strong, persistent updraft of warm moist air. The approaching cold front helps build the updraft into a cumulus cloud. When the warm air rises and meets the cold air, it condenses, releasing latent heat. The heat helps fuel the thunderstorm.