Transcript 無投影片標題 - Shaw Communications

By: Tim Wei
MY AS 9
Block: A
What is Antimatter?
 Antimatter
is a theory that proposed that
every single individual matter or particle
that makes up our world has an exact
opposite partner particle. These are called
the antiparticles.
Properties of Antimatter
 Antimatter,
specifically, is the partner
particle that resembles our normal,
everyday particles in every property. From
the mass, size to even how it reacts with
other particles. Everything is exactly the
same, except the charge of the particle. A
normal particle with a positive charge
would have an antiparticle of a negative
charge.
Properties of Antimatter
 (continued)
 The
antimatter or antiparticles are also very
special and mysterious in another way. This
property of antiparticles is that antimatter,
unlike the normal particles of our world,
cannot be seen in any way. The only way of
detecting it is through its gravitational pull.
 It is like a mirror world exactly like our
own that we just can’t see.
The Origin of Antimatter
 The
theory was first formally predicted in
the year 1928.
 By an English Physicist named Paul Adrien
Maurice Dirac.
 He was the very first, as believed by many
other physicists, in the history of science to
ever predict things as revolutionary as
antimatter with such courage.
The Origin of Antimatter
 (continued)
 Dirac’s
proposal of such a theory was a
combination of mathematical insights from
many other scientists’ formulas and was
also proven with help of experiments
conducted by other physicists later on.
 One of these insights originated from
Bohr’s model of Quantum theory, published
in the year 1913.
The Origin of Antimatter
 (continued)
 Dirac’s
prediscovery of antimatter was first
just from his interest and attempt in solving
the meaning of the math behind the newly
developed Quantum Mechanics. For during
the 1900s, it was the time when Niels Bohr
founded the new Quantum theory through
Johann Jakob Balmer’s 1885 formula on the
frequencies of light of hydrogen spectrum.
The Origin of Antimatter
 (continued)
 After
Balmer’s formula has triggered the
discovery of basic Quantum Mechanics and
so influenced Dirac’s works. Yet another
origin of the Quantum theory that really
founded this field of Physics was taking
shape. In the year 1925, Werner Heisenberg
has successfully found the mathematical
framework for today’s Quantum Mechanics.
The Origin of Antimatter
 (continued)
 It
was these contributions that led to Dirac
being able to describe electrons using a
formula that incorporated both relativity and
the Quantum theory.
 This was when a problem of the formula
arose.
 The equation allowed electrons to have
negative energy.
The Origin of Antimatter
 (continued)
 This
was what really triggered the birth of
antimatter, because the equation is mainly
based on squares and as we know for each
square there are a positive and a negative
square root. So, Dirac reasoned that the
possibility of an electron with positive
energy would be the same as one with
negative energy. Since it’s predicted in the
math.
Invisibility
 If
Dirac’s predictions were true, then how
can one go about finding it? Since no one
has ever seen such things as “antiparticles”
let alone finding one for each and every
known particles that make up our world.
 A main problem to this was that
antiparticles are invisible and can’t be seen
in any way.
Blind Search
 Though
people can’t see these antiparticles
and have said that it was never observed. In
fact, it already has.
 It was common during the 1900s to use
cloud chambers to study cosmic rays
encountering Earth. Particles leave behind
tracks as it passed through the chamber.
And sometimes one could see a distinct trail
somehow traveling the opposite way.
Blind Search
 (continued)
 These
are the antiparticles that were
observed and these later supported Dirac’s
prediction on mirror particles.
Atom Colliders
 Later
on in the 1930, physicists used the
concept of that particles could be collided
and combined to release energy and the
energy set free would form particles. This
was the start of using atom accelerators to
study particles and mostly of antiparticles.
Atom Colliders
 (continued)
 This
was the era of huge accelerators being
able to speed particles near the speed of
light evolving from the classical cloud
chambers. Many antimatter discoveries
were made like so.
Antiparticle Partners
 Thus
through the aid of advance in
technology, the field of antimatter was able
to achieve great accomplishments. Many
particle partners have already been found.
 For example, positrons, antiprotons,
antineutrons, and antineutrinos.
Antimatter in the Cosmos
 Antimatter
could be found not only as tiny
particles or forms of atoms. Scientists
believed that they have recently observed
creations of the mirror particles. Such as
mirror planets and mirror stars which are
invisible objects in space, but physicists
have yet to confirm their existence.
Bibliography
 Works
Cited
 Antimatter:Mirror of the Universe. 2000-2001. CERN. 6
Feb. 2004 <http://livefromcern.web.cern.ch/livefromcern/
antimatter/index.html>.
 Siegfried, Tom. Strange Matters:Undiscovered Ideas at
the Frontiers of Space and Time. Washington D.C. : Joseph
Henry Press, 1950.
 Primack, Joel. “Antimatter”. World Book. 1991 ed.
Activity

Please answer the following questions:

1. Briefly in your own words, please describe what
antimatter is.

2. Please incorporate details about proof that shows
antimatter do exist. Also put down your own ideas
(minimum of two points) on how this theory could
otherwise be proven correct or incorrect.

3. Please shortly state your opinions on whether antimatter
has an impact on people’s everyday lives or not.