When my kids are bored, we usually try a new science activity. In this case, we had a few minutes to kill and decided to try one of our favorite experiments, the leak proof bag science experiment. This science experiment demonstrates how polymer chains work, and it looks just like magic to little ones. Why won’t the bag leak when it has huge holes in it? Kids will love this mixture of messy play and science and it’s perfect for the combination of curious kids and a warm afternoon.

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

Leak Proof Bag: Quick Science Experiment for Kids

Have a few minutes to kill? Why not try the easiest science experiment ever? The leak proof bag is always a hit with kids, and it’s so easy to do! You’ll need just a few things:

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

  • Sharp pencils
  • Plastic baggie
  • Water

Make sure your pencils are really sharp. If they aren’t, you might get leaks anyway.

Fill the bag with water and seal it up tight.

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

Hold the bag up and tell the kids to poke a pencil through. Some might hesitate, but go ahead and tell them to go for it. If they don’t poke the pencil through with confidence, it might still leak.

Poke the pencil through both sides of the bag.

It doesn’t leak!

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

When the pencils are removed, a shower of water leaks out. Use this water to play in, or use it to water the garden!

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

Kids will love trying this activity on a hot day.

Leak Proof Bag Science Explained

Kids will love trying the classic science experiment of the leak proof bag! Just a pencil and a bag produces the most impressive science demonstration.

Flexible plastic is made of polymer chains. The polymers have many molecules inside of them. When the pencil goes through the bag, the molecules in the polymer chains surround the pencil, sealing it up tightly and preventing leaks. But when you remove the pencil, the molecules don’t move to seal the hole, allowing the water to escape.

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