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Weather kid of the month: Punctured water bag

Posted at 8:53 AM, Jun 04, 2021

GRAND RAPIDS — Have you ever tried sticking sharp pencils through a plastic bag full of water? What do you think would happen?? The West Michigan Chevy Dealer weather kid of the month learned the science behind this experiment showcasing polymers.

Let’s get started and figure what happens when we puncture this bag for of water. Here’s what you need.

- Plastic baggie
- Water
- Sharpened pencils (must be sharp)

Step 1: fill the plastic bag a little more than half-way with water

Step 2: seal the plastic baggie

Step 3: make sure you have perfectly sharpened pencils and quickly puncture the baggie all the through

Step 4: watch what happens!

What happened?? Did the pencil poke a hole in the bag?? Is water leaking out? What did you expect to happen?? The scientific magic happening here is all due to polymers! A polymer is like a long chain of molecules that are all bonded together to make up a lot of items we use in our everyday lives including many plastic products. Polymers are flexible, lightweight and leak-proof!

So here’s whats happening… When you stab the plastic bag the polymers move apart. Since the polymers are flexible, when you stab the pencil through the bag, the polymers push back toward the pencil and form a temporary seal. This seal prevents the water from leaking out the holes the pencil made. Of course if you remove the pencils the holes remain because you have permanently pushed the polymers aside then allowing water to leak out.