Weather & NatureNGSS* K-ESS2-210–15 min

Nature Detectives

How a beaver changes a stream, and other evidence of animals changing their world. A narrated earth science lab for kindergarten.

Open the lab Try the free lab

“Nature Detectives! See how a busy beaver changes a stream.”

A stream through the woods with a beaver on the bank

In the lab

What your child does

Helps a beaver build a dam and sees a stream turn into a pond; compares before and after; then, for five pictures, says who changed the place (the claim) from the clues in the picture (the evidence) and what they needed (the reason): food, water or a home.

1
Wonder
A stream in the woods. A beaver walks in.
2
Guess
Can one little beaver change a whole stream?
3
Build
Tap the stick pile six times. Each time the beaver carries a bundle into the stream. Over the first three loads a dam grows and the water deepens. Over the next three it becomes a wide pond with a stick lodge, and the beaver swims home.
4
Compare
Drag a before/after slider over the same spot. Which picture is "after"? Why did the beaver do it? (A safe home.)
5
Nature detective
Five evidence photos. For each, tap who changed it, then what it needed. Squirrel holes → food; roots cracking a sidewalk → water; a nest → a home; an anthill → a home; a house built where trees were cut → a home.
Badge
The big ideas in a sentence, a badge, and a printable lab record.

A beaver carrying sticks into a stream — Build: carry sticks for the beaver's dam

A half-built beaver dam across the stream — The dam grows and the water rises

A finished dam, a wide pond and a beaver lodge — A stream becomes a pond, with a lodge

A photo of holes in a lawn with picture buttons: bird, squirrel, ants — Nature detective: who changed this place?

The standard

K-ESS2-2*

Children construct an argument, supported by evidence, for how plants and animals (including people) can change their environment to meet their needs.

Core idea: Earth's Systems
Science practice: Engaging in Argument from Evidence
Grade: Kindergarten (ages 5–6)

Read K-ESS2-2 on nextgenscience.org

For grown-ups

Talk about it

"How do you know a squirrel did it?"
"Why did the tree's roots crack the sidewalk?"
"How have people changed our street?"

Try it for real

Go on a walk and hunt for evidence: holes in a lawn, a cracked sidewalk, a nest, an anthill, a garden someone planted. For each, ask "Who changed this, and why?"

Weather & Nature