Believe it or not, a portion of Earth’s water isn’t entirely made out of H2O molecules.
Less than a century ago, the hydrogen isotope deuterium – 2H was discovered. It is often simplified to “D”. It led to the discovery of another kind of water with the chemical formula 2H2O, also known as D2O.
There is an essential difference between D2O and regular water.
A regular hydrogen atom contains one proton within its nucleus.
However, the deuterium isotope has a neutron in addition to the proton, thus giving it a greater mass. The increased mass led to the name of “heavy” water.
Heavy water is on average 10% denser than usual water.
Ingesting deuterium in D2O can lead to mishaps in bodily chemistry, meaning that it is not recommended to drink heavy water, at least not in high doses, scientists say.
An international team of researchers led by first authors and biochemists Natalie Ben Abu and Philip E. Mason, who explained:
“There is anecdotal evidence from the 1930s that the taste of pure D2O is distinct from the neutral one of pure H2O, being described mostly as ‘sweet’.”
Tests in rats proved that too much heavy water consumption could be fatal to animals.
“Despite the fact that the two isotopes are nominally chemically identical, we have shown conclusively that humans can distinguish by taste (which is based on chemical sensing) between H2O and D2O, with the latter having a distinct sweet taste,” stated senior author and physical chemist Pavel Jungwirth of the Czech Academy of Sciences.
A taste-testing experiment carried on 28 participants revealed that more significant proportions of heavy water were perceived as tasting sweeter than regular water.