bubble chamber project

UNIT 7: Electromagnetism BCLN PHYSICS 12 - Rev. Apr, 2015

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Bubble Chamber ~ Project Name: ___________

Potential Credits: /10

Using a pencil, answer the following questions/report. The lab is marked based on clarity of responses,

completeness, neatness, and accuracy. Do your best! Please ensure that any data measured (or recorded)

includes the appropriate number of significant digits (only one uncertain digit).

Modern physics has primarily become the study of quantum mechanics and particle physics. Particle

accelerators such as CERN "smash" fundamental particles together and examine the shrapnel of the

collisions using a simple and effective method involving a Bubble chamber. The short-lived particles

resulting from these collisions leave visible trails through these chambers that allow physicists to

determine the fundamental properties of these particles.

Your task is to research how a bubble chamber is constructed and then to apply the laws of

electromagnetism and circular motion to describe the characteristics of four particles that have left a trail

in a mock bubble chamber photo.

While there are many good sites explaining how these bubble chambers work and can be interpreted, one

particularly good site can be found at the link below to get you started:

http://teachers.web.cern.ch/teachers/archiv/HST2005/bubble_chambers/BCwebsite/index.htm

Part 1: How does a Bubble chamber work?

Answer the following questions in the form of a short essay. Keep it simple and ensure that all points

below are covered:

 What is a Bubble chamber? Describe the basic components.

 How are the trails created?

 How does one "read" the trials photographed inside a bubble chamber? Why do charged particles

follow a curved or spiral path once inside the chamber? What must be present for this to happen?

 Why do some particles spiral clockwise while others spiral counter clockwise?

 Describe all of the variables that are responsible for the direction and diameter of the path

created.

 What does is mean if a particle does not curve inside the chamber?

 What is bremsstrahlung and why does this cause some particles to spiral inside the chamber?

Be sure to include a bibliography siting all of the sources you used to find answers to the above. Be sure

that you interpret the information to a grade 12 level and answer in your own words as this will ultimately

lead to better understanding.

UNIT 7: Electromagnetism BCLN PHYSICS 12 - Rev. Apr, 2015

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Part 2: Interpret the Bubble chamber picture below

 The simulated Bubble chamber picture above shows four unknown particles created as a

result of a collision between two particles following circular paths.

 The magnetic field, B, is represented by the dots on the page (out of the page).

Write the equation of motion that represents to four, charged particles above. Solve your

equation for r. You may include the following variables in your formula: m, r, v, q, B and any

fundamental constants.

Equation of Motion

UNIT 7: Electromagnetism BCLN PHYSICS 12 - Rev. Apr, 2015

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Using the picture above complete the table below that fully describes the nature of the four

particles. Use the following constraints:

 You may assume that the magnetic field is constant for all.

 Particles D and C were used as a controls and are both Alpha particles (Helium Nuclei)

 A and D move at the same speed, v1.

 Particle A has a charge of ±2e

 vC is five times that of vB

 Particle B has a charge of ±e

 Note that the diagram is scaled. Each of the magnetic field dots are 10 cm away from

adjacent dots.

Justify your decisions with your equation of motion above.

Path Charge (explain) Relative mass Relative Velocity

A

B

C

D