Fill a small, plastic zip-lock baggie with water. Carefully seal the baggie.
Quickly pierce the baggie with a sharp pencil forcing the pencil through
one side and out the other. Look! No leaks. Find a few more pencils
and puncture the baggie again and again. What do you think will
happen if you pull one of the pencils out of the baggie?
Lesson Title: Baggie Pencil Puncture
Objectives: Observe the properties of polymers.
Materials: Small zip-lock baggies, sharp pencils, water
Key Question: What will happen when a sealed, baggie-full of water is
punctured by pencils?
Engage: Fill a zip-lock baggie with water. Seal it. Ask students to
speculate what they think will happen when the water-filled baggie is
pierced by sharp pencils.
Explore: Quickly plunge a pencil into and out of the baggie. Observe
what happens. Insert several other pencils and observe what happens.
Explain: Molecules called polymers cause the baggie to stretch and seal
around the pencil preventing the water from escaping.
Evaluate: Write a description of the experiment, draw a diagram, and
explain what happened.
J.Tuschl
MNPS
2000