What Happens When You Drink Heavy Water

Water itself is fascinating. Deuterium oxide, water's slightly overweight brother, is even more interesting. What happens when you drink it?
Shelby Rogers

What will you do for the sake of science? If you’re Cody from Cody’s Lab you risk radiation and even poisoning your body.

But hopefully, his passion for science also made him check out the risks before he started this video.

And what does Cody want to achieve?

I love that Cody reminded me that science—chemistry specifically—is so intricate, even one proton or neutron can result in a total transformation.

Water itself is fascinating. And as humans, we’re reliant on it.

But one change in the chemical structure and what we need becomes what we should fear.

Deuterium oxide, water's slightly overweight brother, is even more interesting than water. But what is heavy water and why do we call it overweight? Unlike regular dihydrogen monoxide, deuterium oxide contains hydrogen with a mass of 2, meaning that a neutron has joined in with the proton. This doubles the mass of the hydrogen and makes the deuterium oxide 10 percent heavier than regular water you consume daily.

And ‘heavier’ isn’t an abstract notion. When frozen, it sinks rather than floats like a typical ice cube.

Even though Cody says it tastes sweeter than regular water, please don’t replace the liquid in your water bottle with this. What happens when you drink it? Can you drink heavy water?

Too much heavy water can be toxic, as it slows down the body's chemical reactions. Cody from Cody's Lab decided to subject himself to some heavy water testing. And to make sure his findings weren’t subjective, he asked a friend to taste too. Their findings were the same. However, they didn't drink nearly enough to do significant damage. Or so we hope.

He likened the taste to the sweetness of hay or grass (which we'll take his word for). For obvious reasons, heavy water shouldn’t be found in most homes. There isn’t much use for it there.

But Cody wants to use it for slowing down neutrons. Obviously, this isn’t something that should happen in your body’s chemistry. But in a science lab, it can only result in fascinating experiments.

Even without getting too complicated heavy water’s characteristics are remarkable.

You’d think one neutron doesn’t make a huge difference. But simply because the molecule is bigger its heat capacity rises and it won’t evaporate as easily as normal water. It actually feels colder on your skin than normal water.

And of course, science should always involve some fun! Watch Cody as he discovers heavy water’s elevated heat capacity lets you have fun with ice cubes. The molecules freeze instantly and stick ice to your fingers.

Though he jokes about possible lead poisoning from when he tried making heavy water himself, we believe he stays safe in all his experiments. For this video, he opted to buy heavy water. The layman can take up to 20 years to produce enough of it to do experiments with. And Cody didn’t want to wait any longer.