Now here's a great trick and a fun way to keep cool in the summer!
In this month's 20 Minute Lab, we'll use some household items to see how some forms of plastic are leak-resistant, even when you poke holes in it!
The supplies for this experiment are very simple, and it's a great one for a sunny day. It'll go fast, but you can extend the fun by experimenting with different materials to see what happens.
What's going on?
Plastic bags are made out of something called a polymer. A polymer is a type of molecular structure that is a chain of repeated units - like beads on a necklace. ('Poly' means 'many', so polymer means 'many' units.)
Most bags are made of a particular polymer called low-density polyethylene (LDPE), which has a lot of branching atoms on its chains of polymers. This makes it very flexible.
LDPE is a very common material because it is light, tough, leak resistant and inexpensive. Perfect for packing material and bags!
When the pencil was poked through the bag, the long flexible molecules formed a seal around the pencil, so the water didn't leak out!
But if you try removing the pencils, the hole remains because the polymers were permanently squeezed aside by the pencil and can't return to the original shape. So when you're done, you can pull out the pencils to make a summer shower!
Try these variations to keep the fun going:
What happens using these materials? What changes? What works best?
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