Turbulence visualized

Use pearlescent soap and colouring to visualize the swirls and movement of water.
Science content
Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7)
Earth/Space: Water cycle, Water conservation (2)
Earth/Space: Sustainable practices, Interconnectedness (2, 5, 7)
  • water
  • pearlescent liquid soap (containing glycol stearate or glycol distearate)
  • food colouring
  • white tray or clear sided bottle
  • optional: chopstick, ruler, other items to move water around/over in the tray

Mix 3:1 water:soap in a bottle or tray, gently to keep bubbles to a minimum. Add a couple of drops of food colouring.
Move the water around: tip the bottle back and forth or drag a finger through/blow on water in the tray.
The pearlescent particles show the movement of the water.
Watch the swirls (turbluence) in the water, and find the sometimes unexpected patterns that result from water flow.

For discussion on ocean currents:
In the ocean, tides and winds push the water around. Obstacles such as land or underwater mountains create turbulence as the water hits them. All this movement of the water, much of it turbulent and moving in complex patterns, both on a large scale (e.g. along a coastline) and small scale (e.g. around a reef) churns and mixes the oceans' water.
See “Perpetual Ocean from NASA” for excellent video of turbulence patterns in the world's oceans.
Water movement brings food to animals that can't move, and moves nutrients and heat around.
Some animals have a profound effect on ocean water mixing e.g. krill move en masse to the ocean surface to feed on algae, creating a moving current of water that brings nutrients from the bottom of the ocean to the surface. Phytoplankton (single-celled plants) at the ocean surface can then feed on these nutrients. When they die they sink to the bottom, cycling nutrients back to the deep ocean.….
Some animals use these ocean currents to migrate: Loggerhead turtles migrate from Florida to the open ocean (where the young are safer), then return as adults. Atlantic Leatherbacks travel from Indonesia to Nova Scotia to feed on jellyfish. Pacific Leatherbacks have the longest migration on Earth: they are born in Japan, migrate to Mexico to feed on crabs, then head back to breed, nest. The Green Sea Turtle rides the East Australian Current, though does not go out into the open ocean (Crush in Finding Nemo).

For discussion of the movement of air in our atmosphere:
The turbulence patterns in the tray are the same as the turbulence patterns made by air flowing in our atmosphere (as both water and air are fluids, so behave similarly). When air flows past islands, mountain ranges or other obstacles, turbulence patterns are created. Visual of atmospheric turbulence patterns shown by clouds:

Attached documents

The bottle is less messy, but you have less control over the patterns, and they are not as interesting. Tray recommended if the set up/clean up can be dealt with.
This activity from the Exploratorium:

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5
Gr 6
Gr 7