Watch the following short video about nuclear fusion.

There are different kinds of fusion reactions. Most of these reactions involve the isotopes of hydrogen called deuterium and tritium. Here are two types of fusion reactions:

• The proton-proton chain – This is the fusion reaction of stars such as the sun.
1. Two pairs of protons form to make two deuterium atoms.
2. Each deuterium atom combines with a proton to form a helium-3 atom.
3. Two helium-3 atoms combine to form beryllium-6, which is unstable.
4. Beryllium-6 decays into two helium-4 atoms.

These reactions produce high energy particles (protons, electrons, neutrinos, positrons) and electromagnetic radiation (radio waves, microwaves, infrared, visible light, ultra-violet, x-rays, gamma rays).

The following animation shows the proton-proton chain fusion as it occurs in the sun.

Source: Inside our Sun a deeper look, ogniank, YouTube




• Deuterium-tritium reactions – One atom of deuterium and one atom of tritium combine to form a helium-4 atom and a neutron. Most of the energy released is in the high-energy neutron.

A deuterium nucleus consists of a neutron and a proton.

A tritium nucleus consists of two neutrons and a proton.

The following animation demonstrates a deuterium-tritium reaction. (Neutrons are white in this animation. Protons are red.)

In your notes, describe what is happening in the animation.

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Two nuclei come together and form a helium nucleus with two protons and two neutrons. That leaves a single neutron which breaks away during the reaction.