N AM E _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ P R D _ _ _ _ _ D AT E _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
WHAT IS NUCLEAR FUSION
(AND WHAT MAKES THE SUN
SHINE?)
Every day, you enjoy the effects of nuclear fusion, probably
without even realizing it. What is nuclear fusion? Well, before I
explain that, let’s take a quick refresher course in atomic theory.
Everything in the universe is made up of atoms. Inside atoms
there’s a nucleus, positively-charged protons, and negativelycharged electrons.
Amazingly, it’s the fusion of these smaller-than-microscopic atoms
that powers our sun and provides both heat and light to earth.
Here’s how it works:
Nuclear fusion is a reaction where two atomic nuclei fuse
together to create a larger nucleus. There are various kinds of
nuclear fusion, determined by what kind of atom starts the
process and what kind of atom finishes the process. Our Sun
uses proton-proton fusion. It begins with hydrogen atoms and
ends with helium-4.
This process involves several steps. First, two protons fuse to
form a deuterium, among other things. Then a proton and a
deuterium fuse and form helium-3. Then two helium-3 atoms form
helium-4. This process releases a tremendous amount of energy.
That energy is released in the form of electromagnetic
radiation, and is important for us, because it provides light, and
heat to Earth.
Our sun fuses, on average, about 716 million tons of hydrogen
each second!
You need a tremendous amount of heat and pressure for nuclear
fusion to occur. Stars, including our sun, have both. The amount
of pressure in a star heats it up to sufficient temperatures for this
process to unfold. And this process is so powerful we can feel the
heat of the sun from 93 million miles away and can see stars that
are many, many light years away.
What about nuclear fission? Well, fusion and fission are
different, and FISSION can produce some pretty deadly effects
here on earth when utilized in certain ways! Yep, that kind of way!
Nuclear fusion is the process we’ve covered today. Fission is the
opposite process as things break down and you “split the atom”.
Stars can’t continue nuclear fusion forever. Eventually they’ll run
out of energy. But, that day won’t come for at least 5 billion years
for OUR Sun.
Everyone is now probably thinking…What about nuclear power
plants and nuclear bombs that were used in war? Is that FUSION
or FISSION? Remember, FUSION is a reaction where two
atomic nuclei fuse together to create a larger nucleus and in the
process release energy. FISSION is the process in which a large
nucleus splits into two smaller nuclei with the release of energy.
There are two main types of nuclear weapons: atomic bombs,
which are powered by fission reactions similar to those in nuclear
reactors [power plants], and hydrogen bombs, which derive their
explosive power from fusion reactions.
An atomic bomb slams together two pieces of fissionable
material, usually uranium-235 or plutonium-239. This releases its
energy instantaneously as atoms inside it split in an uncontrolled
chain reaction. On August 6, 1945, an atomic bomb called Little
Boy was dropped on the Japanese city of Hiroshima, followed
three days later by another, called Fat Man, on Nagasaki.
Hydrogen bombs fuse together hydrogen atoms to form heavier
helium atoms, releasing far more energy than a fission bomb.
Two isotopes of hydrogen are used – deuterium (𝐻𝐻 1 2 ) and
tritium (𝐻𝐻 1 3 ). Hydrogen bombs have never been used in war
and are thousands of times more powerful than atomic bombs.
For questions 1-7 identify each as a fusion or fission (You may use google
search)
1. Used in nuclear power plants:
2. Occurs on the sun:
3. More power per gram:
4. A larger nucleus divides to make a smaller nucleus:
5. Two hydrogen atoms fuse to make a helium atom:
6. An atomic bomb:
7. A hydrogen bomb:
8. Why can’t we use fusion reaction in a nuclear power plant?
9. Why is it so hard to dispose of nuclear waste?
10. What are the benefits to having a nuclear power plant nearby?
11. What are the hazards to having a nuclear power plant nearby?
Fill in the blanks.
12. There are two types of nuclear reactions, fusion and fission. ______________
involves fusing particles together. This is the nuclear reaction that occurs in the
sun. Fission involves _______________ a heavy nucleus into smaller particles. This
is the reaction that produces nuclear energy.
13. Compare and contrast FISSION and FUSION in terms of energy production,
particles involved and examples.