Fourth Grade · Science · week 29

Stream-table investigations

Conduct a stream-table investigation modeling how flowing water erodes and deposits sediment, and relate water flow rate to erosion rate.

A stream table is a simple model: a shallow tray filled with sand or soil, tilted slightly, with water poured at the top to act like a stream. Watching where the model stream cuts into the sand, and where it drops sand back down, lets you observe erosion and deposition happening in minutes instead of years.

Changing how fast the water flows changes how much erosion happens. A slow trickle barely moves the sand, while a fast pour cuts a visible channel and carries sand a long way before dropping it. This mirrors real rivers, where a fast flood can erode far more material than the same river on a calm day.

📋 For the teacher
Teach it (10–15 min):
  • Build a simple stream table using a baking tray or plastic bin, damp sand or potting soil, and a pitcher or bottle of water; tilt the tray on a book.
  • Test a slow trickle first, observe and describe the channel, then rinse and reset the sand for a fast-pour trial.
  • Have your child sketch or photograph the channel shape after each trial to compare them side by side.
  • Connect the results directly back to week 28's vocabulary: which parts show weathering, erosion, and deposition in the model?
Talk about it:
  • What changed in your model stream when you increased the water flow?
  • Where did most of the deposition happen in your tray, and why there?
  • How does this small model help explain what happens in a real river during a storm?

Mastery looks like: They can run a controlled stream-table test comparing flow rates and explain that faster flow produces more erosion and longer sediment transport.

Common stumbles: Changing more than the flow rate between trials (different sand, different tilt); describing the results without connecting them back to erosion and deposition vocabulary.

Homework for this lessonType it, write it with a stylus, or print it for pencil & paper.open →
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