Photodissociation of the Hydroxyl Radical (OH)
The hydroxyl radical (OH) is sort of a piece of a molecule. It is made up of one oxygen atom and one hydrogen atom. One way to make OH is to knock a hydrogen atom off of a water molecule (H2O).
This movie shows how an ultraviolet (UV) photon can break apart the hydroxyl radical. When the photon hits the radical, it adds energy to the radical. The extra energy breaks the bond between the oxygen atom and hydrogen atom. The two atoms fly apart! This is called photodissociation.
You need the latest version of the Flash player to see this movie.
Photodissociation of Water
Photodissociation of Oxygen
Photodissociation of Nitrogen
Shop Windows to the Universe Science Store!
Our online store
includes fun classroom activities
for you and your students. Issues of NESTA's quarterly journal, The Earth Scientist
are also full of classroom activities on different topics in Earth and space science!
You might also be interested in:
Most things around us are made of groups of atoms bonded together into packages called molecules. The atoms in a molecule are held together because they share or exchange electrons. Molecules are made...more
Light is very strange. Sometimes it is best to think of light as a series of waves. At other times, it is useful to think of light as a swarm of particles. When we think of light as particles, we call...more
Photons are tiny bits of light and other kinds of electromagnetic radiation. Photons can sometimes break apart molecules. When this happens, it is called photodissociation. When a photon runs into a molecule,...more
Nitric acid is a very strong acid that can burn your skin. Nitric acid has nitrogen, oxygen, and hydrogen atoms in it. There is a very tiny bit of nitric acid gas in Earth's atmosphere. Nitric acid is...more
Sulfuric acid is a very common type of acid. Acid rain has sulfuric acid in it. Acid rain harms plants, fish, and other living things. A type of air pollution causes acid rain. When people burn fossil...more
Methane is a kind of gas. There is a small amount of methane in the air you breathe. A methane molecule has carbon and hydrogen atoms in it. Methane is a greenhouse gas. That means it helps make Earth...more
Ammonia is a kind of gas. Ammonia molecules (NH3) have hydrogen and nitrogen atoms in them. The air you breathe has a tiny bit of ammonia in it. When plants and animals die and decay, they give off ammonia....more