Why Do Snack Bags Puff Up When You Drive Into the Mountains?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do snack bags puff up when you drive into the mountains?

The Big Idea

Snack bags puff up in the mountains because the air outside gets thinner! A sealed bag keeps the air it had when it was packed. So when the pressure outside drops, the air inside pushes out.

Trapped Air

Step one: trapped air. A sealed snack bag traps air at the pressure of where it was packed. That air is stuck inside the bag, with nowhere to go. The bag is soft and can stretch.

Thinner Outside

Step two: lower pressure outside. When you drive up a mountain, the air around the bag gets thinner. There is less pressure pressing in on the bag.

Bag Swells

Step three: the bag swells. The air inside pushes outward, so the bag puffs up like a pillow. When you come back down, the pressure squeezes the bag again.

A Closer Look

Let's take a closer look! The bag is sealed down low, with low-level air inside. Then you drive up the mountain. The pressure outside drops. And the bag puffs up like a little pillow.

Quick Facts

Quick facts! Water bottles can also crunch when taken down from the mountains. A bottle sealed up high holds thin air, so the sides can squeeze in. When you go down, the thicker air pushes in on the bottle. It is the same idea in reverse.

Think Like a Scientist

Now, think like a scientist! Next time your family drives up a hill, ask a grown-up to check a sealed snack bag. Look at it at the top and at the bottom. Which one looks puffier? Tell your family what you found out.

Outro

Snack bags puff up because the outside air pressure gets lower. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!