Key Stage 4 - Particle Detectives

Looking back in time

Notes for teachers

At a glance

In this lesson, students explore how physicists are collecting and using evidence from the Large Hadron Collider (LHC) to learn more about the origins of the Universe. They begin by watching an animation set in the LHC, and learn that physicists are using the LHC to try to recreate the conditions immediately after the Big Bang.

In the main part of the lesson, students take part in a jigsaw activity in which they use selected web sites to research the roles of four LHC detectors. Which particles are each detector designed to detect? Which theories are physicists testing? To conclude, students discuss some important questions, including the role of international collaboration in science, and what happens if newly-collected data does not agree with established theory.

Learning Outcomes

  • Studentsunderstand that physicists are trying to learn more about how the universe started.
  • Students understand that physicists do this by trying to recreate the conditions immediately after the Big Bang, examine the data thus produced and then refine our models of the universe and the Big Bang.

Possible Lesson Activities

  1. Starter activity
  2. Show the animation ‘A quick look around the LHC’ to the class.
  3. Pause the Animation at the point where we see the ATLAS detector from the outside, with the collisions about to take place [1 min 41 sec]. Explain to the group that physicists use telescopes to make direct observations and measurements of the Universe. Over several hundred years, this has enabled physicists to work out the relative sizes, positions and motion of the objects in our Solar System and of distant stars and galaxies.
  4. By examining this model of the Universe, physicists have developed theories about how our universe has developed, with the central idea being the Big Bang. However, although we can model the universe since the moment of the Big Bang, we don’t really understand what happened during the Big Bang. Physicists use the LHC to recreate the conditions of the Universe fractions of a second after the Big Bang to find out more about the particles that were present and their properties.
  1. Jigsaw Group activity: Researching the different LHC detectors
  2. Divide the class into three groups and provide each with Pupil Worksheet 1, 2 or 3. Ask each group to research a different LHC detector:
  3. Group 1: Worksheet 1 - CMS and ATLAS [products of high energy collisions in general]
  4. Group 2: Worksheet 2 - LHCb[matter and anti-matter]
  5. Group 3: Worksheet 3 - ALICE[conditions fractions of a second after Big Bang]
  6. Ask each group to explore which theories each detector is testing and how. You might like to show them the LHC rap as an overview (see our top external links). Each group completes their own section of Worksheet 4 for sharing in the next stage.
  7. Homegroups are now formed so there is a member from each of the groups in the first stage. The expert from groups 1, 2 and 3 feed back their research in turn and pupils fill out that section of Worksheet 4. By the end, Worksheet 4 should be completed by all pupils.
  1. Plenary
  • Once the class have completed Worksheet 4, ask them to discuss the following questions:
  • What is the name of the theory or model that scientists are trying to test at the LHC?
  • Would scientists be able to test this theory with only one of these detectors?
  • Would one group of scientists from any one country be able to develop these experiments on their own?
  • Arethere other big scientific projects/experiments which need to be designed like CERN in order to succeed?
  • What happens if the scientists take measurements that don’t agree with the existing theory?