Science ideas for preschoolers – Part 1: Stream table science

Teach young children about how streams and erosion work in waterways where they live.

Preschoolers are fascinated by the world around them. Most of them ask lots of questions and conduct science experiments without even realizing they are doing it. What happens when I throw this stick? How high can I stack these rocks? What happens when I chase those animals? This is the first in a series of articles on science activities about the natural world that anyone can conduct with preschoolers. This can be done within a family, in a day-care setting, as part of school activities or with any group working with preschoolers. The ideas for this two-part series focuses on water.

What preschooler doesn’t like getting wet and playing in the mud? (I am an adult and I still enjoy it!) On a rainy day kids watch the way the water moves down a driveway. They enjoy making dams, bridges, canals and levees and watching how the water direction changes completely with just a few adjustments on their part.

You can set up an experiment by taking a long plastic or wooden table/board with a lip or an edge, and putting sand or soil on the surface. Elevate one end of the table, and either pour water from a pitcher, or have a hose at the high end of the table. Let the kids push the dirt around and experiment on their own, or ask some of the following questions:

  1. What parts of the river are moving the fastest? The preschoolers can have races with small toys or sticks in the stream.
  2. Where is the sand being eroded? Look at the inside or outside of a curve.
  3. What happens if you block off part of the stream? Does it matter if the blockage is dirt or something more solid?
  4. Would you build a house next to this stream? If so, where would you put it? You can use toy houses to demonstrate this. It can be fun to watch the stream move and “sink” the house.
  5. Can you do anything to stop the erosion? Placing small potted plants with root systems into the sand can demonstrate how plants can prevent erosion. Placing rocks, pieces of wood or other materials can also prevent erosion. Which works better?
  6. Try using a piece of rain gutter or pipe to control a section of stream. Can you control the stream or does it go around?
  7. Vary the intensity of the water flow in the stream. Does that change erosion rates?
  8. Can you make water flow uphill? Give it a try!
  9. Make an island in the middle of the stream. How does that affect the flow?
  10. Try splitting the stream into two. Does it work? Does water appear to prefer one side over the other?

Issues of concern: erosion is a serious problem and sand, silt and mud washing into storm drains and local rivers can make life difficult for your storm sewer system, bugs and fish. When you do these experiments, set up an erosion control structure to stop the sand, silt and mud from washing into storm drains, ditches or local streams. You can do this by placing straw bales between your experiment and a storm drain, ditch or stream. You can also perform this experiment in an area where you have at least 50 feet of vegetation between the experiment and a storm drain, ditch or stream.

For ideas on how to teach preschoolers about the connection between surface water and groundwater, see part two of this article series.

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