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Coloured tracks in Bubble Chamber pictures for education

Author(s): S'Cool LAB, Team, CERN

Contact: scool.lab@cern.ch

Submitted by: barbora.gulejova@cern.ch

Published: June 7, 2023

Coloured tracks in Bubble Chamber pictures for education

Bubble chamber

Dive into the fascinating world of bubble chambers and analyse tracks of high-energy particles with your students. We have developed several activities for advanced high-school students, in which they study bubble chamber photographs and try to work out for themselves what they show. You can find a student worksheet describing these activities (including solutions and additional information for teachers) below. Suggestions for educators Worksheet activity 1: How does a bubble chamber work? Students read a short text and learn about the different components of a bubble chamber. Worksheet activity 2: Electrically charged particles in magnetic fields. Students apply the right-hand-rule to identify tracks of positively and negatively charged particles due to their track's curvature in magnetic fields. Worksheet activity 3: Particle identification and properties. Students learn to distinguish tracks of different particles (electrons, "Compton electrons", positrons, and protons) and calculate the momentum of a given particle track. Worksheet activity 4: Particle transformations. Students analyse the transformation of a pion. Watch a demonstration of a superheated liquid produced by microwaving pure water, which is too dangerous for the classroom. Watch a lecture by Don Glaser who won the 1960 Nobel Prize for Physics for his invention of the bubble chamber at Berkeley Lab. He discusses how, inspired by bubbles in a glass of beer, he invented the bubble chamber and detected cosmic-ray muons. Find out about recent dark matter detection experiments using bubble chambers from the PICO experiment website and the Fermilab website. Bubble chamber art: Bubble chamber patterns also look great as seasonal decorations (e.g., made using the technique of paper quilling) or on dresses. What other creative ideas can your students come up with? Online bubble chamber exercises: Find more advanced online exercises on Peter Watkins’s website. Additional material Read more about an easier version of this classroom activity in 'Science in School': Woithe, J., Schmidt, R., Naumann, F. (2019). Track inspection: how to spot subatomic particles, Science in School, 46 In French: Comment suivre les particules subatomiques à la trace In Spanish: Análise da trajetória: Como identificar partículas subatómicas In Italian: Alla ricerca delle traiettorie: come individuare le particelle subatomiche Where can I find bubble chamber photographs? The images used the activity we propose were produced by the 2 m-long bubble chamber at CERN in 1972. This chamber was filled with 1150 litres of liquid hydrogen cooled to 26 K (–247°C). The bubble chamber was exposed to a beam of protons from CERN’s proton synchrotron PS with a momentum of 24 GeV/c. Scans of the original photographs, as well as images with coloured tracks, can be found online (link below).



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