Introduce the the activities, then students rotate through them:
1. Stream flow:
Investigate how water flows in rivers and streams. A slow flow of water will move over the sand, move it around and and make channels. You can add rocks to block the flow and see how it changes.
2. Warm/cold/salty water flow:
Add clear water to a little tube. Drip one of the coloured waters down the side of the tube. See where it layers and how it flows. Try different combinations.
The soap and food dye added to this water lets you see how the water is moving.
Move your finger through the water, fast or slow, different shapes. Blow or try other ways of moving the water. Let it settle to see a pattern really well.
After all students have done all the activities, ask what they found in each, and relate what they find to how they show how water flow on earth changes our landscape and our oceans. Some key points for each activity:
Streams carve out the landscape, make valleys and mountains.
The rate of flow depends on how wide the stream is.
Rockslides or human building change the flow of the water.
Water carries sand and soil along with it, which gets deposited when the flow is low.
Streams bring water to animals and plants; provide homes in it and by it; bring food to living things.
Warm/cold/salty water flow:
The oceans are not still - they flow around the world. The currents are partly caused by water of different temperatures and different saltiness - cold or salty water sinks, warm water rises.
Ocean conveyer belt “starts” in the North sea, where warm water from the loses heat to the atmosphere and cools. The cold water sinks. Through evaporation and ice formation, the water becomes more salty, so sinks. This cold bottom water moves to make way for the incoming water and flows south of the equator all the way down to Antarctica. Eventually, the cold bottom waters mix with warm water and return to the surface. Upwelling moves nutrient-rich waters from the deep ocean, brings them to the surface, and distributes them around the world.
In the ocean, tides and winds push the water around. Animals also move the water as they swim through it.
The movements mix up the water, bringing food to animals that can’t move, and moves nutrients and heat around
e.g. krill (that whales eat) move all together to the surface of the ocean to feed (on algae), and make a moving current of water that brings nutrients from the bottom of the ocean to the surface. The nutrients feed phytoplankton (single-celled plants) that live at the ocean surface. As phytoplankton die, some slowly sink, carrying nutrients to the deep ocean.
4. A boat making activity replaced the warm/cool/salty water flow for kindergarteners: make boats out of tin foil, and see how many rocks or seeds they can carry before sinking. Then add a little flow to the water by moving a finger or stick through it to see if they can still float.