Soap-Powered Paper Fish
Three related teacher demonstrations: Soap-Powered Paper Fish, Pencils Through a Water Bag, Dry Paper Towel Underwater.
Teaching & key ideas
1. Soap-Powered Paper Fish
Materials: Paper fish with rear notch; water; soap
What you do: Float fish and touch soap into the rear notch.
What students see: The fish shoots forward.
Question: What pushed the fish if nobody touched it?
2. Pencils Through a Water Bag
Materials: Freezer zip bag; water; sharpened pencils; tray
What you do: Push pencils straight through both sides of the filled bag.
What students see: Very little water leaks out.
Question: Why doesn't the hole stay open?
3. Dry Paper Towel Underwater
Materials: Clear tub; cup; paper towel
What you do: Stuff towel in cup, invert cup straight down into water, then remove.
What students see: The towel stays dry.
Question: What is inside the 'empty' cup?
Lesson flow
Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share.
Guiding questions:
Question: What pushed the fish if nobody touched it?
Question: Why doesn't the hole stay open?
Question: What is inside the 'empty' cup?