According to our present Standard Model Theory of Physics, the
Universe started about 13.7 billion years ago as a Big Bang. The Big
Bang was an explosion that pushed the mass of the Universe from a point
outward to form the stars, galaxies and eventually the solar system.
Since the presence of men and women on Earth, there has been a
continuous effort to understand the forces by which nature is made
manifest. This game provides some information on the forces, on the
particles and on the technology devised to create, accelerate, detect
and identify those particles as well as how they are used to make the
world a better place in which to live.
This game introduces some of the concepts of the Standard Model in a
new and exciting way. The game promotes collective work and cooperation.
Students are encouraged to work together as a group to answer the
questions so that everyone can get through the
spiral of evolution. It is certain that some students will get
through before others but their expertise can be called upon when there
are mind-boggling questions. The Universe
is meant to be a cooperative game and students are asked to be
respectful of each other. Students should wait until a student asks for
help in answering a question before they volunteer an answer. Students
are also invited to add questions of their own as well as more particles
to the board.
The objective of the game is for all of the players to get from the
start to the end of the spiral and out to the Universe as quickly as
possible. Once everyone has finished, the game is over.
There can be two to fourteen game-players. Each player chooses a
different game piece that represents an elementary particle and begins
with the roll of a die. A player then moves that number of spaces and
follows the instruction, if any, found on that space. It may take
several games before a student learns the answers to many of the
questions, therefore be patient, pay attention to others students’
answers, self-study and engage in the discussions that arise.
Keep track of the time it takes to finish the game on a time chart in
order to get an idea of how long it takes to play the game. You can also
add cards with new instructions and questions to each stack and also new
particles to make the game more interesting.
If your piece lands on a square with a word written on it, go to that
stack, choose the top card and follow that instruction. Place the card
at the bottom of the pile.
If your piece lands on a square with a written instruction, follow
the instruction immediately.
After answering a question from a card, place the card at the bottom
of the stack to be used again. You can either advance two spaces (or the
number indicated on the card) or obtain an energy card for each correct
answer. You go one space backwards for each incorrect answer (unless
stated otherwise on the card).
Only one die is used in the game after the initial tosses. The first
player throws the die, counts the number of dots and moves his particle
piece that number of spaces around the board. Players must follow the
direction(s) on that space unless they have an
exempt card.
When one arrives within five spaces of entering the Universe, that
player must throw exactly the number of spaces needed to complete the
game. Remember! S/he can only win if all players have crossed the
barrier! The barrier is a simple piece of
paper - not provided by us but which you can easily produce - placed
with a tape on the board on the square that suits you best. We suggest
to put it after square 21 (starting from the Big Bang), i.e. between
"technology" and "accelerators", after the transition bonus jump. The
"almost" winner can decide to help the other players in order for them
to cross the barrier and therefore let him win the game.
Players may assist upon request another player to answer a question
and can pass exempt cards to each other.
Your choice of particles is an important factor in successfully
completing the game, so give careful thought to selecting a particle.
Some particles might have advantages that another one might not have.
Particles taking part in this game are:
- electrons
(black- tops)
- positrons or anti-electrons
( black+ tops)
- negative muons
(purple- tops)
- positive muons
(purple+ tops)
- negative tau
(orange- tops)
- positive tau(orange+
tops)
- neutrinos
(white tops)
Special particles
- photons or gamma rays (yellow tops)
Particle-detector interactions in the game:
|
Particle (player)
|
Hadron calorimeter
|
Lepton calorimeter
|
Radio Frequency cavity
|
| protons |
X
|
|
X
|
| anti-protons |
X
|
|
X
|
| positive Kaons |
X
|
|
X
|
| negative Kaons |
X
|
|
X
|
| positive pions |
X
|
|
X
|
| negative pions |
X
|
|
X
|
| neutrons |
X
|
|
|
| electrons |
|
X
|
X
|
| positrons |
|
X
|
X
|
|
negative muons |
|
X
|
X
|
| positive muons |
|
X
|
X
|
| negative tau |
|
X
|
X
|
| positive tau |
|
X
|
X
|
| neutrinos |
|
|
|
|
photons |
|
|
|
Additional Rules
- A barrier (a simple piece of paper not provided but which you
can easily produce and place with a tape on the board) is placed by
the teacher or the students. It is possible to win the game only if
all players have crossed the barrier.
- The final square contains a question mark. This means that the
player who is about to win has to ask a question to the other
players. This can be a question among those which have already been
asked during the game, or a completely new question which has to do
with Particles, Bubble Chamber, Accelerators, Detectors or
Technology and whose answer can be easily verified by all the
players. Players can volunteer to answer the question: in the
instance of a positive (negative) answer the player will go 3 spaces
forwards (backwards). Players can also decide to challenge the
"almost winner" to verify if s/he really knows the answer to her/his
question. If the "almost winner" answers correctly he can proceed,
otherwise, s/he has to go 5 squares backwards.
- When a hadron (H) or lepton (L) particle lands on its respective
calorimeter (HCAL or LCAL), it loses some of its energy, i.e. two
energy cards (see
below
to find out how to gain them). In the instance where the player does
not have two energy cards, they must go back six squares. The player
can also decide to use one energy card and go back 3 spaces. Our
calorimeters do not affect neutrinos and photons.
- If your piece lands on a square with another particle, this is
considered a collision (i.e. you are producing a collision) and the
particle piece that was there gets kicked back one space while yours
gets kicked forward one space. If the collision occurs with a
particle and an anti-particle (i.e. the same particle with opposite
charge), both particles involved in the collision annihilate and
change into a gamma ray.
- A particle decays when it lands on a space with the word 'decay'
written on it. They must then choose one of the resulting particles
of the decay as their game piece.
Decay modes
in our game:
|
Particle (player)
|
Symbol
|
Decay
|
Notes
|
| protons |
p+
|
|
protons do not decay |
| anti-protons |
p-
|
|
anti-protons do not
decay |
| positive Kaons |
K+
|
K+
=> μ+ + νμ |
player transforms
into a positive muon or a neutrino |
| negative Kaons |
K-
|
K-
=> μ- + anti-νμ |
player transforms
into a negative muon or a neutrino |
positive
pions |
π+
|
π+
=> μ+ + νμ |
player transforms
into a positive muon or a neutrino |
| negative pions |
π-
|
π-
=> μ- + anti-νμ |
player transforms
into a negative muon or a neutrino |
| neutrons n
|
n
|
n
=> p + e- + anti-νe |
player transforms
into a proton, an electron or a neutrino |
| electrons |
e-
|
|
electrons do not
decay |
| positrons
|
e+
|
|
positrons do not
decay |
|
negative muons
|
μ-
|
μ-
=> e- + anti-νe + νμ |
player transforms
into an electron or a neutrino |
| positive muons |
μ+
|
μ+
=> e+ + νe + anti-νμ |
player transforms
into a positron or a neutrino |
negative
tau |
τ-
|
τ-
=> μ- + anti-νμ + ντ |
player transforms
into an muon or a neutrino |
positive
tau |
τ+
|
τ+
=> μ+ + νμ + anti-ντ |
player transforms
into a muon or a neutrino |
| neutrinos |
n
|
|
neutrinos do not
decay |
|
photons |
γ
|
γ => e+ + e- |
player
transforms into a positron or an electron. |
|
|
If you
happen to land in the Radio Frequency (RF) Cavity, either of
the following can occur.
- If you are a negative particle and land in the cavity on
the positive cycle of the voltage, you are accelerated and
can move ahead 4 spaces. Just the opposite happens if you
are a positive particle like a proton, you will be slowed
down and must move back 4 spaces.
- If you are a negative particle and land in the cavity on
the negative cycle of the voltage, you are decelerated and
must move back by 4 spaces. Just the opposite happens if you
are a positive particle, you will be sped up and moved
forward by 4 spaces.
- If a particle lands on an excite or radiate space
(transition bonus or transition setback), it makes a quantum
jump or fall to another energy level. Instead of a
transition bonus (transition setback) you can get (give
back) a quantum of energy, i.e. an energy card.
|
|
Stacks of cards
- Particles - contains question cards on particles and their
behaviour.
- Bubble Chamber - contains question cards on this type of
detector
- Accelerators - contains question cards on accelerators
- Detectors - contains question cards on detectors in general.
- Technology - contains questions on the machines themselves as
well as the spin-off products that make life better or worse.
Energy Cards & Exempt Cards
In nature as well as in this game, energy is only exchanged in
packets, called quanta. In this game, a quantum of energy corresponds
to an energy card.
- Energy cards can be gained by challenging the Universe on your
turn to answer three questions from any of the card piles.
- Energy cards can be lost if you answer two consecutive questions
incorrectly, if you land on a calorimeter (this depends on the
particle you are, see
table)
or they can be given back to the Universe in order to avoid a
transition setback.
- You can give away energy to a classmate who might be in trouble.
- You can save energy by using an exempt card to keep from loosing
your energy.
- Exempt cards can be bought with three energy cards or gained by
challenging the Universe on your turn to answer one question from
each pile (5 in total). Answer correctly all five questions and you
win one exempt card. You can only challenge once every six playing
turns. An exempt card entitles you to escape any unpleasant
situation on the board or on a card from one of the piles. Both
exempt and energy cards can be traded or given to another player.
Further information about particles
Please note that a chart of elementary particles is available as
jpg,
pdf
or
eps
file.
Quarks are the building blocks for protons and neutrons and, more
in general, together with anti-quarks, they make up hadrons. They are
considered to be elementary particles. There are six different quarks
in nature. Quarks are not used in this game. However, as you get
better at playing the game, you are encouraged to modify the game as
your level of sophistication increases. You could, for example,
introduce into the game the collision among quarks and the formation
of hadrons.
Hadrons (particles composed by quarks
and affected by strong interactions):
- p+, proton is in
the nucleus and is composed of three quarks, two up quarks and one
down quark. It was once thought to be an elementary particle. The
proton has a positive (+) charge and a mass of 938 MeV/c2.
- p-, anti-proton
is the anti-particle of the proton. If the two collide they can
annihilate into a gamma ray.
- K+, positive kaon
decays into a positive muon and a muon neutrino. The kaon has a
mass of 494 MeV/c2. In nature there are four basic kaons:
K+, K-, K° and anti-K°.
- K-, negative kaon
decays into a negative muon and a muon anti-neutrino. Except for the
charge, negative kaons behave like positive ones.
- π+, positive pion
has a mass of 140 MeV/c2. In our game they decay only
into a positive muon and a muon neutrino. In nature other decay
modes are possible but with a very small probability.
- π-, negative pion
has a mass of 140 MeV/c2. In our game they decay
only into a negative muon and a muon anti-neutrino. Except
for the charge, negative pions behave like positive ones.
- n, neutron is in the nucleus
and is composed of three quarks, two down quarks and one up. It was
once thought to be an elementary particle. The neutron has no charge
and a mass of 940 MeV/c2.
Leptons: (elementary particles not
affected by strong interactions)
- e-, the electron is an
elementary particle. Electrons have an negative charge of 1 unit
(equivalent to 1.6X10(-19) C) and a mass of 0.5 MeV/c2.
- e+, the positron is the
anti-matter of the electron. If the two collide they can annihilate
into a gamma ray. The positron has positive charge and a mass of 0.5
MeV/c2.
- µ-,
negative Muon can decay into an electron, electron
anti-neutrino and a muon neutrino. The muon behaves almost like an
electron, has a negative charge and has a mass of 106 MeV/c2.
- µ+,
positive Muon can decay into a positron, an electron
neutrino and a muon anti-neutrino. Apart from the opposite charge
(important for their behaviour in radiofrequency cavities), positive
muons behave like negative ones.
- τ-,
negative Tau can decay into a muon, muon anti-neutrino
and a tau neutrino. The tau behaves almost like an electron or a
muon, has a negative charge and has a mass of 1.78 GeV/c2.
- τ+, positive Tau
can decay into a positive muon, a muon neutrino and a tau
anti-neutrino. Apart from the opposite charge (important for its
behaviour in radiofrequency cavities), positive taus behave like
negative ones.
- n, neutrino - There are three types of
neutrinos- muon, electron and tau neutrinos. Neutrinos have
virtually zero mass and travel at the speed of light. It is now
believed that neutrinos can oscillate from one type to another, thus
indicating that they do have a non-zero mass. They can travel
virtually through any matter.
A photon is the particle which makes
up light. It can be formed in an annihilation particle-antiparticle,
e.g. electron-positron, and, in this game, it is not affected by
detectors or radiofrequency cavities.
In nature there are many more particles,
possible interactions and decay modes than the game uses!
Further information about LHC - Large Hadron Collider - and
particle accelerators
The LHC is a synchrotron. A synchrotron accelerates particles by
having them travel around and around in a vacuum tube. The LHC will
have two such tubes placed side by side so that the same kind of
particles - protons - can be accelerated in opposite directions and
then smashed into each other.
The LHC is under construction now at CERN, and will be operational
in 2006. In particular, it will be looking for a particle that
scientists believe responsible for giving all particles their mass.
This particle is called the Higgs Boson.
In order to accelerate while keeping the particles in nice bundles
(i.e. with a small energy spread. They are made speed up if they fall
behind or slow down if they are travelling too fast) as they revolve
around the synchrotron, they pass through an RF cavity.
Four particle detectors will measure the collisions of particles
accelerated by the LHC: ATLAS, CMS, LHCb, ALICE.
Further info:
CERN Public Website,
ATLAS Public Website,
CMS Public website
Further information about particle
detectors
A particle detector does several things
- It reconstructs the interaction
- It identifies all the particles produced
- It measures particle's momenta and energies
- It identifies the type, mass, charge, lifetime, spin and decay
Detectors at the LHC have many layers like an onion, each layer
measuring different properties of the high energy particles passing
through. Detectors are huge machines some standing as high or higher
than 30 meters.
At the center are tracking devices that determine with precision
the particles’ vertex. They are used to pinpoint the collision and to
catch short-lived particles.
Most particles end their journey in the calorimeters. These
detectors measure the energy deposited when particles are slowed down
and stopped. Particles can be identified often by the calorimeter that
they get stooped by.
A Bubble Chamber is a detector that is no longer used. It was a
chamber filled with superheated hydrogen and other gases in which form
small bubbles along the trail of charged particles that travel through
it. Neutral particles like the neutron, K0, ?° and gamma
ray leave no trails. One detects them by knowledge of the decay
process. The bubble trails are then photographed from different
perspectives and the film is studied to provide information on the
types of particles involved in the interaction.
More detailed info.
Answers to the proposed question cards
The questions cards we propose on the game board are intended to be
a collection of suggestions you may find appropriate for your class
and your curriculum. One of the goals of the game is to make students
develop their own questions. You can at every stage get in touch with
us for any further information you may need.
Particles
Q: What particles are the main contituents of cosmic rays at
the sea level?
A: Muons
Q: The behaviour of matter particles is controlled by forces.
Name the four basic forces.
A: Gravitation, Strong Force, Weak Force, Electromagnetic Force.
Q: Name at least one of the main properties of a particle. A
'main property' is what helps you recognize the particle.
A: Energy, Momentum, Mass, charge
Q: Draw a picture which best represents an atom and give the
approximate scale of the particles.
A: Suggestion:
Bubble Chamber
Q: In a Bubble chamber and under the influence of an
electrostatic force of a nearby nucleus, you materialize into an
electron-positron pair. What are you? a) an electron b) a gamma ray c)
a neutrino
A: b) a gamma ray
Q: Name at least one of the Bubble chambers you know.
A: BEBC (Big European Bubble Chamber), Gargamell
Q: Bubble Chambers were machines used to identify elementary
particles from 1950 to the 80s. What machines replaced them? a) radio
b) particle accelerators c) microwaves d) multi-layer detectors
A: d) multi-layer detectors
Q: A bubble chamber gets its name because bubbles are created
by charged particles as they move through the superheated liquid
hydrogen. a) True b) False
A: a) True
Accelerators
Q: When an electron travels near the speed of light in a
circular accelerator, it radiates. The electron: a) gains energy b)
mantains the same energy c) loses energy
A: c) loses energy
Q: What does LEP mean? And what was it?
A: Large Electron Positron collider. It was the electron-positron
collider operational at CERN until November 2000.
Q: Accelerators come in many different sizes and shapes.
Which size does not fit an actual accelerator: a) a donut shape b) a
pyramid c) a long cilinder?
A: b) a pyramid
Q: What is the difference between a circular collider and a
linear accelerator. Name at least an advantage and a disadvantage of
building a circular collider and a linear accelerator.
A: In a circular collider, two beams of particles at the same energy
collide to produce interactions studied by the detectors located along
the accelerators. More than one collision point is possible. In a
circular collider, charged particles radiate. The collision energy is
the double the energy of each beam.
In a linear accelerator particles are made speed up and hit a target.
In order to increase the energy of the particles you need to make your
accelerator very long. Only one collision point is possible. The
collision energy is distributed among the atoms of the target.
Q: In a circular accelerator, the particle is kept in its
orbit as it travels around a circle by what force: a) gravitational b)
electric c) magnetic
A: c) magnetic
Q: What is the maximum speed that a particle can reach in an
accelerator? a) the speed of light c
b)much higher than c c) just below
c
A: c) just below c
Detectors
Q: Detectors in this game cannot stop muons and therefore
they pass through the detector and gain freedom. If you are a muon
advance 3 spaces.
A: Picture
Q: Name at least one of the main properties of a particle. A
'main property' is what helps you recognize the particle in the
detector.
A: Energy, Momentum, Mass, Charge
Q: The best analogy for the structure of a detector used in
particle colliders is: a) onion b) banana c) tomato d) potato
A: a)onion
Q: You are caught in the hadron calorimeter. If you are a
proton you are trapped and all your energy is dissipated. If not, this
card does not affect you. Go back 6 spaces...sorry!
Q: Does a neutral particle leave any tracks in a detector? If
so, in which of the layers?
A: Neutral hadrons leave a track in the hadron calorimeter, neutrinos
do not leave any tracks in a standard detector.
Q: You are caught in the lepton calorimeter. If you are an
electron you are trapped and all your energy is dissipated. If not,
this card does not affect you. Go back 6 spaces...sorry!
Technology
Q: Particle accelerators are used in cancer treatment. a)
True b) False
A: a) True - Today, there are estimated to be around 10000 particle
accelerators in the world, over half of them used in medicine and only
a few in fundamental research.
Q: What is the working temperature of the LHC? a) about 300
degrees below the room temperature b) -17 degrees Centigrade c) zero
degrees Kelvin
A: a) about 300 degrees below the room temperature, that is 2.7
degrees Kelvin. The LHC will be the coldest object in the Universe we
know.
Q: What is the birthplace of the WEB? a) SLAC (USA) b) CERN
c) Hamburg University (Germany)
A: a) CERN
Q: The techniques used to cool down some of the accelerator
elements are now used to preserve food. a) True b) False
A: a) True
Q: The LHC will be the coldest object in the Universe when it
will be operational. a) True b) False
A: a) True - The working temperature will be about 300 degrees
below the room temperature, that is 2.7 degrees Kelvin.
Q: The data flow produced by the four LHC experiments will be
equivalent to:a) every person on the planet talking to 20 telephones
at once b) 100 people making a telephone call at once c) just a few
bites
A: a) every person on the planet talking to 20 telephones at
once
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