Heavy water facts for kids

Heavy water, also known as deuterium oxide (D₂O), is a special type of water. It's different from the regular water we drink because of a tiny change in its building blocks.

The main difference comes from a special kind of hydrogen called deuterium. Regular water mostly has a lighter type of hydrogen called "protium." But heavy water has a much larger amount of this heavier deuterium. This makes heavy water slightly heavier and gives it different properties compared to normal "light water."

What is Heavy Water?

Heavy water is a form of water that contains a special type of hydrogen. This special hydrogen is called deuterium, also known as "heavy hydrogen." Its scientific name is deuterium oxide.

How is it Different from Regular Water?

The main difference between heavy water and regular water is the type of hydrogen it contains.

• Regular water uses a common type of hydrogen called protium (¹H).
• Heavy water uses a heavier type of hydrogen called deuterium (²H or D).

Because deuterium is heavier than protium, water made with deuterium is also slightly heavier. This difference in weight changes how heavy water behaves. It has different physical properties, like its freezing and boiling points, and also different chemical properties compared to regular water.

What is Deuterium?

Deuterium is a special version, or isotope, of hydrogen. Think of it like a twin brother to regular hydrogen, but one that weighs a little more. It has an extra tiny particle called a neutron in its center, which regular hydrogen doesn't have. This extra neutron makes it "heavy."

Where is Heavy Water Used?

Heavy water has some very important uses, especially in the world of energy.

Heavy Water in Nuclear Reactors

One of the most important uses for heavy water is in certain types of nuclear reactors. These are power plants that create electricity using nuclear energy.

• Heavy water acts as a "neutron moderator." In a nuclear reactor, tiny particles called neutrons move very fast. Heavy water helps to slow these neutrons down.
• Slowing down the neutrons is important because it allows the reactor to work efficiently. It helps control the nuclear reaction.
• Because heavy water is so good at slowing neutrons, some reactors, like the CANDU reactors, can use uranium fuel that hasn't been specially prepared or "enriched." This makes it a very useful material for these power plants.

Is Heavy Water Radioactive?

Pure heavy water itself is not radioactive. This means it doesn't give off harmful radiation on its own. However, if heavy water has been used inside a nuclear reactor, it can become slightly radioactive. This happens because it absorbs some of the tiny particles (neutrons) from the reactor.

Images for kids

• 

  "Heavy water" made by Norsk Hydro

See also

In Spanish: Agua pesada para niños