Liquid Nitrogen in a Microwave!

What happens when the world's most beloved cryogenic liquid meets one of the most common household appliances? Find out when we try to microwave liquid nitrogen!

Announcer: Frostbite Theater presents... Cold Cuts! No baloney!

Joanna and Steve: Just science!

Joanna: Hi! I'm Joanna!

Steve: And I'm Steve!

Joanna: A little while ago we received an email from Star of the Sea Catholic School in Virginia Beach, Virginia, asking what happens when you place liquid nitrogen in a microwave.

Well, I just happen to have some liquid nitrogen!

Steve: And I just happen to have a microwave!

Joanna: Let's find out!

Steve: Okay, so this is how this is going to work.

I have two cups of water and Joanna's going to get two cups of liquid nitrogen. We're going to place one cup of water and one cup of nitrogen into the microwave and then blast them on high for one minute. We'll then take the cups out and compare them to the ones that stayed outside the microwave.

Before we get started we'll go ahead and measure the temperature. And both cups of water are at about seventy degrees Fahrenheit. The nitrogen, though, is too cold for me to measure with this thermometer. But we can tell that, since they're boiling, they're both about three hundred twenty one degrees below zero and we can also tell there's about the same amount of nitrogen in each cup.

So, if we're ready, we'll go ahead, load 'em up, set the timer, and away we go!

Okay, time's up!

The cups of water still look alike, but the one that was in the microwave is now about a hundred and forty degrees Fahrenheit whereas the one that stayed outside is still about seventy.

The nitrogen, still too low to read, but they're still both boiling, so they're still the same temperature. And they still have about the same amount of nitrogen in each cup.

So that means the nitrogen that was inside the microwave didn't boil any faster than the one that was outside the microwave. So the water was able to absorb energy from the microwaves, but the nitrogen didn't.

Why is that?

Joanna: Water molecules are polar molecules. That means that they have a positive end and a negative end. Because they're polar, they respond to electric fields. The rapidly changing electric fields created by a microwave cause the water molecule to jitter about. The faster they jitter about, the hotter they become.

Nitrogen, however, is non-polar. This means that they do not respond, or are largely unaffected by, microwaves. The microwave passes through the liquid nitrogen as if it wasn't even there.

Steve: So, to answer the question "What happens when you try to microwave liquid nitrogen?"

Joanna and Steve: Nothing!

Joanna: Thanks for watching! I hope you'll join us again soon for another experiment!

Steve: Hot chocolate?

Joanna: Cold chocolate!

Steve: Cold chocolate?!

Oh, my!

Joanna: Taste it!

Steve: No!

Joanna: Taste it!

Steve: No!

Joanna: It's very tasty!

Steve: Okay...

Joanna: Taste it!

Steve: No!!