Atoms and Nuclear
Energy
Andrea Chiang and Milan Desai
Table of Contents
Matter.........................................................................3
Charge........................................................................4
Protons.......................................................................5
Neutrons.....................................................................6
Electrons.....................................................................7
More about Electrons....................................................8
Different Types of Radioactivity......................................9
Importance of Radioactivity..........................................10
Dangers of Radioactivity..............................................11
Nuclear Power............................................................12
Fission.......................................................................13
Problems with Fission..................................................14
Fusion.......................................................................15
More about Fusion......................................................16
More about Nuclear Power...........................................17
Dangers of Nuclear Power............................................18
Nuclear Weapons........................................................19
Nuclear War...............................................................20
A Look into History: Hiroshima/Nagasaki........................21
Glossary....................................................................23
Illustration Credits......................................................25
About the Authors.......................................................26
M
A
T
T
E
R
The entire universe is made of energy and matter, which
is made of atoms, but what makes up an atom?
These atoms, which are
building blocks of matter,
are made of three small
particles called electrons,
protons, and neutrons.
The protons and neutrons
are tightly bound in the
center of the atom to form
the nucleus, which is
surrounded
by
the
electrons.
Let's explore the properties, such as
charge, of each of these particles –
protons, neutrons, and electrons!
C
H
A
R
G
E
First, all particles have several fundamental, or basic,
properties. One of the defining characteristics of these particles
is charge, which can be positive (+), negative (-), or
neutral (no charge).
Two positive charges or two negative charges
repel each other, while two opposite charges
attract each other. In an atom, protons have
a positive charge and electrons have a
negative one. Neutrons have no charge at all.
Therefore, the nucleus of an atom is positively
charged and attracts the electrons. In the
metric system, this property is measured in
Coulombs (C). This was named after the
scientist Charles-Augustin Coulomb. Scientists
assigned the charge of an electron to be 1.6 x
10-19 C. That's a really small number!
P
R
O
T
O
N
S
What are protons, and where do they come from? Protons
are particles with a positive charge that make up atoms, and
they are much, much smaller. More specifically, they make up
the center of the atom, or the nucleus. Protons cannot even be
seen with an electron microscope, but to explain how an atom
works, we must assume that they exist. All of the protons in the
universe were probably made right after the Big Bang
occurred. Each proton is exactly the same as any other proton
in the universe.
Atoms that have different
numbers
of
protons
are
different elements. So the
type an atom is depends on
the number of protons it has.
For example, an oxygen atom,
as shown on the right, has 8
protons…
An Oxygen Atom
A Helium atom
... whereas a helium atom
only has 2 protons. The
simplest atom is the hydrogen
atom, and it has only one
proton. The heaviest atom,
the atom with the most
protons, is the uranium atom,
which has 92 protons.
Let's look at neutrons next, which
share the nucleus with protons.
N E U T R O N S
Neutrons are tiny particles found in the nucleus of an atom.
Every neutron in the universe is identical, and most neutrons
are found inside of atoms. Like protons, all neutrons were
formed after the Big Bang occurred. However, unlike protons,
neutrons have no charge.
Why do atoms need neutrons if they have no charge?
Neutrons are necessary in atoms because they help keep
protons together. These particles are held together by a strong
force, conveniently called the strong nuclear force. Most
atoms have more than one proton, excluding the hydrogen
atom which has just one proton for a nucleus. Atoms generally
have the same number of neutrons and protons, but some
atoms may have more neutrons.
Did you know? An
electron and a proton can
come together to form a
neutron.
In
neutron
stars,
protons
and
electrons combine and
form neutrons because
there
is
so
much
pressure. Neutrons do
not have a positive or a
negative
charge
like
protons or electrons do,
so they don't push each
other away and can pack
together to form a very
dense star. On the left is
an image of a neutron
star, the tiniest of stars.
E L E C T R O N S
Where did electrons come from? Electrons were in the
universe after the Big Bang occurred as well. Because electrons
have a negative charge and protons have a positive charge,
they attracted one another and formed the first hydrogen
atoms in the universe. As time progressed, more complicated
atoms were formed, such as oxygen, carbon, and sulfur.
Where are the electrons in the atom? The electrons are not
just set loose inside of atoms; they are contained within specific
areas, which are called electron shells. Each shell holds a
different number of electrons. For instance, the first shell holds
just two electrons. Therefore, if an atom has more than two of
these particles, it needs more shells! The shells get farther
away from the nucleus, and each shell can hold more electrons
than the one before it.
M O R E
A B O U T
E L E C T R O N S
However, a shell does not need to be completely filled for
electrons to start filling the next shell. So the biggest atom
known, uranium, has 92 electrons and needs seven shells. If
the last shell of an atom is full (the farthest from the nucleus),
the atom is more stable and stronger. However, if an atom has
an incomplete last shell, it is called a valence shell. Atoms
with a valence shell bond more easily to other atoms with a
valence shell because electrons can be shared between them.
DIFFERENT TYPES OF
RADIOACTIVITY
What are the different types of radiation? In
alpha decay (refer to picture below), helium nuclei
(which have a proton and a neutron) are released.
In beta decay (shown on the
left), energy is released in the
form of electrons. There are two
types of beta decay, but all you
need to know is that in betaminus decay, the atom ends up
with one more proton and one
less neutron, and in beta-plus
decay, the atom ends up with one
more proton and one less
neutron.
Finally, in gamma radiation, a large
quantity of energy is released in the form
of electromagnetic waves, a topic for later.
X-rays, which doctors use to take a picture
of the inside of your body, are actually a
form of gamma radiation.
I M P O R T A N C E
O F
RADIOACTIVITY
If this strange thing called radiation is just a bunch of
protons, neutrons, electrons, and energy, then why is
it so important? Light is a form of radiation; it is a
stream of energy. Radios, televisions, and cell phones
also emit streams of energy to send signals across
the globe; thus, even they use radiation.
Even cell phones use radiation.
By understanding the atom and how it decays,
scientists can figure out how to create these
signals with the properties they want. For
example, we now know how to create blue light
versus red light, transmit signals from radio
stations, and send calls to people on the other side
of the world. In addition, when sharply focused,
high energy radiation can be used to kill cancerous
cells. X-rays and similar energy streams are used
to take a picture of what is going on inside the
body without doing surgery.
2
D A N G E R S
O F
RADIOACTIVITY
Why is it dangerous? If people are around radioactive
materials, it could potentially be very dangerous. High
concentrations of radioactivity can result in genetic changes by
damaging the DNA in your chromosomes. The radioactivity
emitted by objects can easily pass through people's skins. So if
you ever break a bone and need an x-ray, the doctors place a
thick mat over your chest to block radiation from going through
your skin.
Did you know?
Marie Curie was a physicist and chemist who lived from 1867 to
1934. She learned that radiation was significantly more complicated
than Becqueral initially thought. Throughout her life, she paved the
way for modern radiation studies. Although Curie personally
experienced the negative side effects of radiation (she died from
leukemia), she only wanted to focus on the potential medical
benefits of radiation. She also discovered two chemical elements,
polonium and radium, and in 1932, she founded the Radium
Institute. Not only did her work lead to the nuclear model of the
atom, but it also provided a new means by which cancer could be
attacked; if radiation is dangerous to cells, it can be used to kill
cancerous ones.
In fact, even now her journals are so dangerously radioactive that
they must be handled with gloves!
NUCLEAR POWER
What is it? Nuclear power is an energy source that uses
nuclear fission of uranium atoms to generate heat, which
through a series of steps will ultimately produce electricity.
Nuclear fusion can also be used to generate nuclear power, but
as of now, more research needs to be done before this nuclear
reaction will be reliable enough.
What happens in a nuclear power plant. Nuclear fission occurs in the reactor.
How does it work? Nuclear fission has to happen in order for
a nuclear reactor to generate energy. Briefly, fission occurs
when an atom splits into smaller particles and releases a large
amount of energy during the process, which will be discussed in
more detail on the next page. The reason uranium is used is
because it is unstable, and therefore, it can be broken down
more easily into smaller particles. The energy that is produced
transforms into heat energy, which is used to generate
electricity. The heat energy is transferred through a substance
such as water, which turns into steam. The steam turns a
turbine connected to a generator, and the generator produces
the electricity.
F
I
S
S
I
O
N
What happens in fission? In fission, a neutron is fired at an
atom which splits in half, releasing a neutron and a vast
quantity of energy. To be specific, scientists use Uranium235 or
Plutonium238. The subscript “235” or “238” shows the number of
nucleons (protons and neutrons) in the atom. Uranium and
plutonium are used because they have a large number of
nucleons; there is potential for the release of much more
energy. In addition, both of these elements are stable enough
to be used in fission.
The photograph above shows how fission
happens. A neutron is fired at the uranium or
plutonium atom, which splits in half and
releases another neutron. This one is used to
split yet another Uranium atom. Imagine how
much energy is released from chain reaction of
a few ingredients even smaller than a speck of
dust.
P R O B L E M S
F
I
S
S
I
W I T H
O
N
Fission has its problems. Uranium is very hard to find, unlike
the hydrogen used in fission. Hydrogen can be generated by
just electrocuting water with a normal battery. But uranium has
to be dug out of the ground in mines and imported from various
countries at various prices. In addition, fission reactions result
in the formation of other elements that decay very slowly.
These dangerous particles can last for decades, and burying
them underground only creates ground pollution.
Uranium Ore Mine
F
U
S
I
O
N
What happens in fusion? Fusion is a reaction that combines
many atoms into one atom. Nuclear fusion is the energy that
stars use to "shine" and hydrogen bombs use to explode. It
happens when two particles fuse together to yield a larger
nucleus and energy. Take D-T fusion, for example. Deuterium
and tritium, two different isotopes of hydrogen (forms of
atoms that have the same number of protons but different
numbers of neutrons) fuse together to produce an alpha
particle, a neutron, and a vast quantity of energy.
An alpha particle is simply a helium nucleus, which has two
protons and two neutrons. In fusion reactors (which have not
been built yet), the alpha particle heats up some more
deuterium and tritium to produce more energy, alpha particles,
and neutrons. This chain reaction is supposed to continue for a
long period of time, but no one has figured out a way to control
it in reactors yet. In fusion bombs, however, a fission reaction
triggers enough heat and pressure for a fusion reaction to
continue.
M O R E
F
U
S
A B O U T
I
O
N
The most simple nuclear fusion reaction is converting hydrogen
into helium. Products such as neutrons and energy are
produced. Like fission, this nuclear reaction does not happen in
one step. A fusion reaction produces energy because a helium
atom weighs less than the initial hydrogen atoms that were
used to make it. The total mass at the end of the reaction is
always less than the total mass from the beginning of the
reaction, and the lost mass is turned into energy.
Converting hydrogen into helium is the nuclear
fusion reaction that is used to provide energy for
stars, like our sun, as shown above.
\
M O R E
A B O U T
NUCLEAR POWER
How is nuclear power used? About 17% of electricity
worldwide is produced by nuclear reactors. However, nuclear
fission can be useful in other ways. Atom bombs use the same
concept of splitting an atom to generate large amounts of
energy. In medicine, cancer treatment and scanning devices
use radiation, which is energy produced by atoms that have
emitted smaller particles.
Cattenom Nuclear Power Station in France
What are its advantages?
Advantages: This type of power
is more efficient than other types
of power, meaning it produces
more electricity for the same
amount of substance used. Less
waste is produced, so it pollutes
the
environment
and
atmosphere less. The waste is
also stored in capsules that are
protected from fire, water, or
earthquakes. The process is
consistent enough to rely on for
many years.
What are its disadvantages?
The pollution is radioactive, but
new technology is making the
process much cleaner and safer.
There is also the possibility of
leaking radiation. The initial
investment of building a nuclear
reactor
is
very
expensive;
however, in the long run, the
expenses to keep the power
plant running are cheaper. Also,
accidents could happen as a
result of human error.
D A N G E R S
O F
NUCLEAR POWER
Nuclear power plants can generate a huge amount of energy,
but they are also possibly dangerous. Recall that fission is a
chain reaction; the neutrons released continue to hit other
uranium or plutonium atoms, releasing even more energy and
more neutrons. In a bomb, this occurs so quickly that a fireball
forms and explodes. In a reactor, the goal is not to produce an
explosion but to generate heat, so the reaction must be
controlled. Scientists do this by continually absorbing a large
percentage of the neutrons released; however, a single mistake
by a regulator (people who monitor the reactions to make sure
things are not getting out of hand) can ignite a giant explosion
in a matter of seconds. A famous example is the 1986
Chernobyl disaster in Ukraine, where two people died from the
initial explosion of a nuclear power plant and 28 people died
from radiation sickness within the next four months.
On the left is a picture of the
Chernobyl power plant. After
the explosion occurred in a
reactor, the people came to
this bridge to view the
reactor from a distance.
Rainbow
colored
flames
could be seen at the plant,
higher than the smokestack.
At
first,
people
were
reassured that the radiation
was minor, but they later
found out that the fatal
radiation had blown onto the
bridge.
NUCLEAR WEAPONS
Modern nuclear bombs (or atomic bombs) consist of both fission and
fusion reactions. There are two parts of the bomb: In part A, a
plutonium core is surrounded by two layers. The first layer is full of
neutrons, and the second has explosives (such as TNTs). When the
outer layer explodes, it compresses the neutrons into the plutonium
so much that scientists call it “supercriticality,” and a small fission
reaction occurs. This emits x-rays that hit part B.
This part of the bomb is a plutonium rod surrounded by a special
fuel that has deuterium and tritium (the two isotopes of hydrogen
used in fusion). This, in turn, is surrounded by polystyrene foam, the
same type of foam that comes in packaging. When the x-rays from
part A hit the foam, it melts into extremely hot plasma and
compresses the plutonium, causing it to fission. The heat from this
reaction ignites the deuterium/tritium fuel, sparking a fusion
reaction. The neutrons generated from the fusion cause even more
plutonium to fission. A fireball starts to form.
NUCLEAR
WAR
Nuclear weapons are so destructive that many countries,
including the United States, have agreements not to use
them on each other. A single atomic bomb can kill
millions of people instantly, destroy an entire city, and
afflict millions of people with radiation poisoning. High
levels of radiation can afflict people with serious health
affects including cancer and disorders that ultimately
lead to death. In addition, an explosion can kill all plants
and animals for miles. If one bomb alone can do this,
then imagine the consequences of a nuclear war. It has
not happened, but the idea is frightening. Some
scientists say that it could lead to the end of civilization.
We don’t know if that is true, but there is no doubt that
there would be terrible consequences.
A Look into History:
Hiroshima/Nagasaki
In 1945, World War II had turned into a war against Japan. The
Manhattan Project, a covert government operation in which the first
atomic bomb was built and tested, had produced the first nuclear
bomb for use in the war. President Harry S. Truman issued a
declaration telling the Japanese to either surrender or face “utter
devastation of the Japanese homeland”. This warning was ignored,
and on August 6, 1945, the first atomic bomb was dropped over
Hiroshima, Japan. Nearly 80,000 people, roughly 30% of the city
population, were killed instantly from the blast, and another 70,000
were injured. Those who stared directly at the bright white light from
the explosion had their eyes burned, and the scorching heat
immediately vaporized people nearest to the blast. All life within a
one mile of the blast site was destroyed, and structures within four
miles were set on fire. Those who did not die from the explosion or
fires developed radiation poisoning, which caused thousands of cases
of deadly cancer in the months that followed. All around the world,
people were shocked by the news of the blast. Japanese military
offices were unable to contact the people at Hiroshima, and there
were rumors of a terrible explosion, but no major air raid had been
detected. When people were sent to observe the situation in the city,
pilots were astounded to find that in place of the city there was a
giant mushroom cloud above a leveled landscape on fire.
Hiroshima Before
Hiroshima After
A Look into History:
Hiroshima/Nagasaki
Hiroshima, however, was not the only city attacked. Three days
later, a second nuclear bomb was dropped over the Japanese city of
Nagasaki. Another 40,000 to 70,000 people died instantly, with
thousands more dying in the following days from radiation sickness.
Just like in Hiroshima, the blast leveled the landscape, destroying
everything within one mile of the impact site. Fires spread for
another two miles, destroying thousands of buildings including
schools and hospitals. Finally, the shocked emperor Hirohito
surrendered to the United States, ending the World War II. August 9
was the day the world realized that technology had become powerful
enough to destroy human civilization.
What the terrain looked like after the bombings.
G
L
O
S
S
A
R
Y
Alpha decay: a form of radioactive decay in which the helium nuclei are
released
Atoms: the building blocks of matter. They are composed of protons,
neutrons, and electrons.
Attract: when a particle experiences a force compelling it to move toward
another particle
Beta decay: a form of radioactive decay in which a neutron is converted to a
proton and electron and the electron is released.
Charge: a fundamental property of particles. Charges can be positive or
negative. Like charges repel and opposite ones attract.
Deuterium: an isotope of hydrogen consisting of one proton and one neutron
Electrons: carriers of energy. They have a negative charge and surround the
nucleus of the atom.
Elements: atoms with different numbers of protons in the nucleus
Energy: a fundamental concept in the universe; something that results in
motion. Einstein proposed that energy and matter are interchangeable, which
led to the production of nuclear bombs.
Fission: a phenomenon in which a neutron smashes into a heavy nucleus,
splitting it and releasing a huge quantity of energy along with another neutron.
This neutron proceeds to hit the nucleus of another atom, releasing even more
energy.
Fusion: a phenomenon in which two subatomic particles (i.e. protons and
neutrons) combine into one, releasing a huge quantity of energy in the process.
Gamma radiation: a form of radiation consisting of energy in the form of
electromagnetic waves.
Hiroshima: a Japanese city destroyed by the first nuclear bomb ever used in
war. 70,000 people were killed instantly.
G L O S S A R Y
(
2
)
Ions: atoms that have the same number of protons but possibly a different
number of electrons. Different ions of the same element have different charges.
Isotopes: atoms that have the same number of protons but possible a
different number of neutrons. Different isotopes of the same element have
different masses.
Matter: anything that has mass and takes up space. Einstein proposed that
energy and matter are interchangeable, which led to the product of nuclear
bombs
Nagasaki: a Japanese city destroyed by the second nuclear bomb ever used in
war. 50,000 people were killed instantly, which forced the Japanese empire to
surrender, ending the Second World War.
Neutrons: found in the nucleus of the atom. These have no charge and are
there for stability.
Nucleus: a dense collection of protons and neutrons found in the center of an
atom
Plutonium: an element with 94 protons. It is commonly used in fission
reactions because it's both heavy and unstable.
Pollution: harmful contamination of the ground, air, or water with toxic
materials
Protons: carry a positive charge in the nuclear of the atom.
Radiation: a stream of energy or particles released by an unstable nucleus
Repel: when a particle experiences a force compelling it to move away from
another particle.
Tritium: an isotope of hydrogen consisting of one proton and two neutrons.
Uranium: an element with 92 protons. It is commonly used in fission reactions
because it’s both heavy and unstable.
X-rays: a form of gamma radiation. Doctors use these to take pictures of the
inside of the body
ILLUSTRATION CREDITS
*Book page background and about the authors background made by Andrea Chiang*
http://www.nurmuhammad.com/smc/atoms.gif
http://www.historyforkids.org/scienceforkids/chemistry/atoms/pictures/helium.jpg
http://www.historyforkids.org/scienceforkids/chemistry/atoms/pictures/oxygen.jpg
http://www.flickr.com/photos/7969902@N07/511103951/sizes/l/in/set-72157
600253743362/
http://www.btinternet.com/~chemistry.diagrams/electron-shells.gif
http://lc.brooklyn.cuny.edu/smarttutor/core3_22/images/chlorineatom.gif
http://info.babylon.com/cgibin/bis.fcgi?rt=GetFile&uri=!!TD435W9M42&type=0&index=2
http://iusedtohavehair.files.wordpress.com/2009/07/parent_xray.jpg
http://library.thinkquest.org/06aug/01335/nuclear.htm
http://www.cartage.org.lb/en/themes/sciences/Physics/NuclearPhysics/Applications/N
uclearWeapons/fission_supercritical.gif
http://iweb.langara.bc.ca/biology/mario/Assets/covalentbond.jpg
http://www.stkate.edu/physics/Astrobiology/alphadecay.gif
http://education.jlab.org/glossary/betadecay.gif
http://www.lancs.ac.uk/ug/hussainw/fusion.jpg
http://lh5.ggpht.com/_dlkAw43cLC0/SczTfxkN75I/AAAAAAAAEJ8/BH8ytdesdro/s800/
Chernobyl-Today-A-Creepy-Story-told-in-Pictures-bridge.jpg
http://www.mactonnies.com/neoruins.jpg
http://decibel.fi.muni.cz/models/cinema2007/xvanco/1/Nuclear_Power_Plant_Catteno
m.jpg
http://earthscience.files.wordpress.com/2007/01/sun.jpg
http://www.cameco.com/common/images/content/u101/reactor2.jpg
http://www.ionlinephilippines.com/wp-content/uploads/2009/09/Radiation
Cellphone.jpg
http://en.wikipedia.org/wiki/File:AtomicEffects-p7a.jpg
http://en.wikipedia.org/wiki/File:AtomicEffects-p7b.jpg
ABOUT THE AUTHORS
Andrea Chiang was a junior at Mass
Academy at the time this book was
written. She lives with her parents
and younger brother in Northboro,
Massachusetts. In her nonexistent
free time, she enjoys sleeping,
singing, mixing music, dancing,
and learning biology. She is also a
Boston/New England sports fan
who enjoys watching the Celtics,
Patriots, and Red Sox. One of her
favorite animals is a narwhal. She
likes working with young kids as
she is still very much a child at
heart. She hopes that all of the
readers enjoy this book.
Contact him at http://users.wpi.edu/~milandesai
Contact her at http://users.wpi.edu/~acc
Milan Desai was also a junior at
Mass Academy when he coauthored
this book with Andrea Chiang. He
lives
with
his
parents
in
Shrewsbury, Massachusetts. In his
spare time, he enjoys playing video
games on his xBox360, studying
for the SATs, and listening to
music. His favorite types of music
are hip hop and comedy. He likes
to sleep when he is supposed to be
doing homework, like this children's
book. Milan also likes tennis and
roller coasters. He and his coauthor
hope you enjoy this book!