Bottle Holes Stop When Capped
Three related teacher demonstrations: Bottle Holes Stop When Capped, Straw Holds Water With a Finger, Blow Over a Paper Strip.
Teaching & key ideas
1. Bottle Holes Stop When Capped
Materials: Plastic bottle with tiny side holes; water; cap; tray
What you do: Let water stream with cap loose, then tighten cap.
What students see: Water flow slows/stops when air cannot enter.
Question: Why does the cap change the holes at the bottom?
2. Straw Holds Water With a Finger
Materials: Clear straw; colored water
What you do: Dip straw, cover top with finger, lift it.
What students see: Water stays inside until finger is removed.
Question: What is holding the water up?
3. Blow Over a Paper Strip
Materials: Thin strip of paper
What you do: Hold strip under lower lip and blow across its top.
What students see: Paper rises into the air stream.
Question: Why did blowing over it make it go up?
Lesson flow
Predict → observe three demonstrations → compare what changed → choose independent activity station → cleanup/share.
Guiding questions:
Question: Why does the cap change the holes at the bottom?
Question: What is holding the water up?
Question: Why did blowing over it make it go up?