Cloud Chambers and Cosmic Rays

A Lesson Plan and Laboratory Activity for the High School Science Classroom

Giant Solar Tadpoles born in enormous solar explosion (NASA)

Coronal mass ejection shooting plasma into space (NASA) Cosmic ray shower (SLAC)

The Basic Ideas of the Standard Model

Simplification (particle “zoo”) and Unification

Complex systems few, basic entities Both matter and forces included Matter: Quarks and Leptons Forces: 4 forces

Matter Particles

Particleadventure.org

What is it? The best theoretical framework we have for particle physics today.

Force Particles

How do particles create forces?

Electromagnetic force

Some Force Diagrams

Electromagnetic

Strong Nuclear

proton

The Standard Model

• What is it? The best theoretical framework we have for particle physics today.

• It has been a remarkable success BUT we know it is incomplete

• So, what does the phrase “STANDARD MODEL” mean? A unification of all matter into two types of particles A unification of the Electromagnetic and Weak Nuclear forces A description of the interaction between fundamental particles in terms of the exchange of fundamental force particles

• Some things it does not do: It does not unify the Strong and Electro-Weak forces (GUTS?) It ignores Gravity, so does not tell us anything about how it might be unified with the other forces ( TOE ?) It does not explain why there are so many generations of particles It does not explain the disappearance of anti-matter in the Universe.

Let’s focus on this lepton…

And mention this one…..

• “Cosmic Rays” = subatomic particles

• “Cosmic Rays” = unsure of their origin (magnetic fields)

• Composed of various types of particle:

Primary Cosmic Rays

• Hydrogen nuclei (87%)

• Helium nuclei (12%) – “alpha particle”

• Nuclei from heavier elements

• High speed electrons – “beta particles”

Secondary Cosmic Rays

• Particles slam into gas atoms in upper atmosphere

• Fragments shower down and/or disintegrate: pions muons + neutrinos pion electron + positron +

gamma rays

• Muon and neurtrinos make it to the surface of the earth

What are Cosmic Rays??

Let’s build a detector……Cloud Chamber

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Teacher Resources •The Standard Model •Cloud Chamber•Science Curricula •Event Diagrams •Accelerators Workshops •Physics First Lab Information and Tours •Visit Wilson •A Virtual Tour of Wilson •Online Brochure K-12 Opportunities •After School Programs •High School Internships

Undergraduate Programs •REU

Science of Bubbles Atoms for kids

Light and Optics

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http://www.lepp.cornell.edu/public/outreach/