The equation E = mc 2 is probably the most recognized symbol of physics. This equation tells us that...
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The equation E = mc 2 is probably the most recognized symbol of physics. This equation tells us that matter and energy are really two forms of the same
The equation E = mc 2 is probably the most recognized symbol of
physics. This equation tells us that matter and energy are really
two forms of the same thing.
Slide 3
If you put enough energy in one place, you can create matter.
If you make matter disappear, you get energy.
Slide 4
The law of conservation of energy becomes a law of mass-energy
conservation.
Slide 5
The amount of energy it takes to create a kilogram of matter is
calculated using Einsteins formula.
Slide 6
Nuclear reactions also obey the energy conservation laws. The
total amount of energy before the reaction has to equal the total
amount of energy after the reaction. Energy stored as mass must be
included in order to apply the law of conservation of energy to a
nuclear reaction.
Slide 7
The energy from mass is given by Einsteins formula E = mc 2
where m is the mass of the particle. Even small amounts of mass
contain tremendous energy because c 2 is such a large number
90,000,000,000,000,000 (Ninety quadrillion!!!)
Slide 8
A fission reaction splits up a large nucleus into smaller
pieces. A fission reaction typically happens when a neutron hits a
nucleus with enough energy to make the nucleus unstable. Fission
breaks the nucleus into two smaller pieces and often releases one
or more extra neutrons. Some of the energy released by the reaction
appears as gamma rays and some as kinetic energy of the smaller
nuclei and the extra neutrons.
Slide 9
A nuclear chain reaction occurs when the fission of one nucleus
triggers fission of many other nuclei. In a chain reaction, the
first fission reaction releases two or more neutrons. The two
neutrons can hit two other nuclei and cause fission reactions that
release four neutrons. The four neutrons hit four new nuclei and
cause fission reactions that release eight neutrons. The number of
neutrons increases rapidly. The increasing number of neutrons
causes more nuclei to have fission reactions and enormous energy is
released.
Slide 10
The atom bomb is based on the uncontrolled fission of uranium
235 or plutonium 239.
Slide 11
In a conventional nuclear power plant, the U235 fission
reaction is used to generate electricity.
Slide 12
Today, about 20 percent of U.S. electric power comes from
nuclear fission plants.
Slide 13
Nuclear fusion is a nuclear reaction in which two or more
atomic nuclei collide at a very high speed and join to form a new
type of atomic nucleus. During this process, matter is not
conserved because some of the matter of the fusing nuclei is
converted to photons (energy).
Slide 14
Stars, like the sun, make energy from fusion reactions, because
the core of a star is both hot and very dense. All of the energy
reaching Earth from the sun ultimately comes from these fusion
reactions in the suns core.
Slide 15
When a single heavy nucleus splits into two or more lighter
nuclei (fission), the sum of their masses is less than the mass of
the original nucleus. Some mass is missing, and some energy is
released. When two light nuclei fuse into a single heavier nucleus
(fusion), the mass of the heavier one is less than the sum of the
masses of the two light ones. Some mass is missing, and some energy
is released. In both events (fission and fusion), the missing mass
has been converted to energy.
Slide 16
Radioactive decay, also known as nuclear decay or
radioactivity, is the process by which a nucleus of an unstable
atom loses energy by emitting particles of ionizing radiation
Slide 17
If the amount of missing mass is 'm', and you multiply 'm' by
the square of the speed of light 'c 2 ', the answer you get is the
amount of energy that was released 'e'.
Slide 18
How much energy is contained in matter with a mass of 2kg? E =
(2) (3x10 8 ) 2 E= 1.8x10 17
Slide 19
A piece of carbon-14 that originally had a mass of 2 kg is
later found to have a mass of 1.75 kg (due to radioactive decay).
How much energy was released? E = (.25) (3x10 8 ) 2 E= 2.25x10
16