You probably wouldn’t believe me if I told you we could fill a bag with water and then poke holes in it and the water wouldn’t leak out. But you’d be wrong because that is exactly what we are going to do!
Prepare to be amazed at the experiment, then grab a plastic baggie and pencil and try it yourself.
Why Doesn’t the Water Leak Science Experiment Video
- Plastic Baggie
- Sharpened Pencils
Step 1 – Fill a plastic baggie a little more than 1/2 way full of water.
Step 2 – Seal the baggie.
Step 3 – Quickly stab a sharpened pencil through the baggie.
Step 4 – Try stabbing multiple pencils through the baggie. Why doesn’t the water leak?
How Does the Experiment Work?
The magic of this experiment lies in polymers. Polymers are long chains of molecules that make up many items we use in our everyday lives – specifically plastic items. Zipper top plastic baggies (like the one used in our experiment), plastic grocery bags, plastic water, and soda bottles, and plastic food packaging are all made of polymers. Products made of polymers are flexible, lightweight, leak-proof, and low in cost to produce.
Think of polymers as long chains of beads. When you stab a pencil through the bag, the polymers move apart. This is the same as if you stuck a pencil between two chains of beads. Because polymers are flexible, when you stab a pencil through the bag, the polymers push back toward the pencil and form a temporary seal. This prevents the water from leaking out of the holes. If you remove the pencils from the bag, the holes will remain in the bag because you have permanently pushed the polymers aside, allowing water to leak out.
I hope you enjoyed the experiment. Here are some printable instructions: