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Difference Between Ordinary Water And Heavy Water

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You know your regular tap water is H₂O, but have you ever heard of heavy water? D₂O, to be specific. It might sound fascinating, but heavy water is actually a thing, and it has some amazing properties that make it very useful in certain situations. So what is this mysterious stuff, and what makes it so special?

The main difference between heavy and ordinary water is that heavy water has a higher Deuterium concentration. Deuterium is a hydrogen isotope that has an extra neutron in its nucleus. This makes heavy water about 11% heavier than regular water.

This blog post will further discuss the difference between ordinary and heavy water and how they are both important for different reasons!

What is Ordinary Water?

water h2o

Ordinary water, also known as light water, is the most common type of water on Earth. It consists of two hydrogen atoms and one oxygen atom and has a molecular weight of 18 g/mol.

Light water is important for many reasons. First, it makes up most of the Earth's surface water, which is vital for all life. Second, light water is used in most human activities, such as drinking, cooking, and bathing.

Third, light water is also used in many industrial processes, such as cooling and heating. This is because it has a lower boiling point than heavy water and can therefore be easily turned into steam.

What is Heavy Water?

heavy water d2o

Heavy water, also known as deuterated water or D20, is water that has been enriched with the hydrogen isotope deuterium. Deuterium is an isotope of hydrogen with a neutron in its nucleus, which makes it heavier than regular hydrogen.

Heavy water has a molecular weight of 20 g/mol and is about 11% heavier than light water. Despite this difference in weight, heavy water looks and feels quite the same as regular water.

Heavy water is mainly used in nuclear reactors, which is used as a moderator to slow down neutrons. This makes it possible to sustain a nuclear chain reaction necessary for generating electricity.

Heavy water is also used in medical research, as it can be used to study the effects of radiation on living tissue.

Differences Between Ordinary And Heavy Water

Some of the differences between ordinary and heavy water are:

Deuterium Concentration

Deuterium is an isotope of hydrogen with a proton and a neutron in its nucleus. "Heavy water" (D₂O) is water that contains a higher proportion of deuterium than "ordinary water" (H₂O).

Heavy water is therefore used in some nuclear reactors because it absorbs neutrons better than ordinary water. This makes it more efficient at slowing down the nuclear reactions that take place in the reactor.


While ordinary water is vital for everyday life, heavy water plays an important role in nuclear reactors and other scientific applications.

Heavy water contains a higher concentration of the hydrogen isotope deuterium. This gives the water a slightly different chemical structure than ordinary water, which mostly contains hydrogen isotope protium.

Heavy water is used as a moderator in some nuclear reactors because it slows down neutrons, making the reactor more efficient. In addition, heavy water is used in scientific research to study the properties of atoms and molecules.

Although heavy water is not necessary for everyday life, it plays an important role in some scientific and industrial applications. By understanding the different properties of heavy and ordinary water, we can better use this vital resource.

Thus heavy water has more scientific applications than ordinary water, which is widely used in almost all day-to-day activities.

Density and boiling point

The boiling point of heavy water is slightly higher than that of ordinary water, and its density is also greater. These properties arise because heavy water has Deuterium, an isotope of Hydrogen, in its molecules.

The increased density of heavy water means it is less likely to evaporate than ordinary water. This is why heavy water is used in some nuclear reactors, as it can better absorb neutrons. The extra weight of the atoms makes it harder for the molecules to escape from the liquid state, so the boiling point is higher.

Comparison Chart: Ordinary Water Vs Heavy Water

ParametersOrdinary WaterHeavy Water
Boiling Point100°C101.4°C
Deuterium ConcentrationLowerHigher
Fit for consumptionYesNo
Freezing Point0°C3.8°C
UsesDrinkingScientific purposes (reactors, etc.)
Molecular Weight18 g/mol20 g/mol


Is drinking heavy water safe?

Heavy water is safe to drink in very small amounts. However, it can be toxic if you drink large amounts of it. Therefore it is better to be safe and stick with drinking your normal water.

How is heavy water made?

Heavy water is made by a process called electrolysis. This process uses electricity to separate water molecules into their parts: hydrogen and oxygen. The hydrogen atoms are then distilled, and Deuterium is reacted with Oxygen to produce heavy water.

What are the uses of heavy water?

Heavy water is used in nuclear reactors to help control nuclear fission. Finally, it has been used in medicine to treat certain types of cancer.

What are the dangers of heavy water?

Heavy water can be dangerous if you drink too much of it. It can also be dangerous if it leaks into the environment, as it can contaminate groundwater and soil. Therefore, it is important to be careful with this type of water and ensure it is properly contained.

Is ordinary water used for reactors?

Ordinary water is normally used in light water reactors. Heavy water reactors use heavy water to help control nuclear fission.

Is there any similarity between the two?

There are some similarities between ordinary and heavy water. They are colorless, odorless, and tasteless.


So there you have it! The difference between heavy and regular water is pretty interesting, right? While you probably won't be using heavy water in your everyday life, it's still good to know that this fascinating substance exists!

Feel free to comment and discuss about the article in the comment space below if you have any information or remarks to add. If you think we made a mistake, you can also report it there.
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About the Author: Nicolas Seignette

Nicolas Seignette, who holds a scientific baccalaureate, began his studies in mathematics and computer science applied to human and social sciences (MIASHS). He then continued his university studies with a DEUST WMI (Webmaster and Internet professions) at the University of Limoges before finishing his course with a professional license specialized in the IT professions. On 10Differences, he is in charge of the research and the writing of the articles concerning technology, sciences and mathematics.
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