“Much to learn, you still have” are the famous words of Jedi master Yoda to Count Dooku when he faces his old Padawan in Attack of the Clones.
These words have inspired a series of successful events aimed at school pupils organised by the Department of Physics at the University of Liverpool.
The Physics of Star Wars provides a strong theme for engaging students with advances in accelerator science, an exciting new area of physics that will be of increasing importance in coming years.
The most high profile particle accelerator is the Large Hadron Collider in Switzerland, and many of the technologies used in everyday life today, such as electronics and the internet, have been enabled by research originating in accelerator science.
Based on our experiences working with schools in the North West we would like to share our ideas and resources to help others to use this theme to explore a number of areas in the curriculum.
Physics of Star Wars
The Physics of Star Wars provides an opportunity to explore what is science and what is fiction in the famous films.
The aim is to show students in years 7-9 how futuristic technologies, brought to life in the world of Star Wars, may potentially become possible with current developments in accelerator science.
We start our events with a short talk in which I show short scenes from the films. This gains the attention of the pupils, breaks the ice and starts a discussion with them about whether the science holds up.
This has a direct connection with the school curriculum and the following areas have proven to work very well to stimulate discussion:
- Space travel – speed of light, sound propagation in space, mass and acceleration
- Light sabres – light propagation, physics of lasers and plasma
- Scenes with R2D2 and C3PO – coding, machine learning, fundamentals of logical decisions
Following the talk, we divide participants in groups of around 10 and each group then follows a set of specific learning activities, which are all Star Wars themed.
In the following sections, you will find a few selected setups that have been effective in helping the pupils engage and interact with our demonstrations.
Learning and teaching materials are included in each section so you can take these ideas directly into your classroom. Finally, the information boxes explain in more depth how these fundamental concepts relate to accelerator research and should give you some ideas of how to refer to current cutting-edge research in your teaching.
The (electrostatic) power of the dark side
Scene in Star Wars: Emperor Palpatine, also known as Darth Sidious, was one of the most dangerous Sith lords to have ever lived. He was able to call on his hatred and create “force lightning”; the ability to cast bolts of electricity-like force energy from the tips of his fingers.
Demonstration: It is possible to create real-life force lightning using a Van de Graaff generator.
This high voltage generator has made generations of hair stand up and is a very popular interactive teaching tool in secondary schools and science museums. A person that touches the generator can, once charged, cast an electricity “lightning” onto another person nearby.
Feeling the electrostatic force around a Van de Graaff generator.
The Van de Graaff generator is also ideal to explain the physics of particle accelerators.
Most modern large-scale accelerators use changing electromagnetic fields: electric fields accelerate the particles to incredibly high speeds and magnetic fields are used to control the beam of particles and its trajectory.
Activity – creating a salad-bowl accelerator
This process can be demonstrated using a Van de Graaff generator, a metal-coated ping-pong ball – and a salad bowl! The following 10 steps allow your students to construct a salad bowl accelerator themselves:
- Prepare a ping-pong ball by coating it in conductive paint. This should be done a few days before the lesson as the paint takes some time to dry.
- Using two pieces of aluminium tape cut each one so it is around 2 cm wide and long enough to cover the entire bowl across its diameter.
- In the middle of these strips, trim each side so the width is reduced to around 1cm in the centre.
- Put the aluminium strips into the bowl at an angle of 90°, forming a cross at the centre of the bowl.
- Add eight short, narrow (1cm) aluminium strips. These should be long enough for one end of the strip to run over the edge of the bowl when the other end is placed close to the centre of the bowl.
- Using four of the narrow strips, stick one strip in each of the spaces between the cross. They should not touch the centre.
- With the remaining four narrow strips of tape, join all the narrow strips together on the outside of the bowl.
- Using aluminium tape, crocodile clips and banana plugs the setup can then be connected to the earth terminal of the Van de Graaff generator and the cross to its high voltage dome; the leads should not touch each other!
- Drop the ball into the bowl and turn on the generator.
- Watch the ball spin inside the bowl. Do not forget to discharge the Van de Graaff generator after the experiment!
We have produced a video about how to build your own salad bowl accelerator: https://bit.ly/3axMP2M. If there is not enough time, you can also prepare the setup before the lesson – which is what we have done for most of our events – and the activities can then focus on a careful observation and detailed discussion of all effects.
Questions for the students to encourage further discussion include:
- Why is the ball spinning in a particular direction?
- Could you make the ball spin the other way around? How?
- How could you make the ball spin faster?
- What happens if you use an uncoated ball? Why?
Safety note: The voltage generated in a Van de Graaff can reach several tens of thousands of Volts, however, the current is very low, i.e. any electric shock is not dangerous to a healthy person.
Operation of the Van de Graaff generator should be supervised by a trained adult and the following basic rules be followed: Earth clips need to be firmly attached, the dome should always be discharged after use by touching it with an earthed object, and one should avoid getting too close to the charged surfaces.
Whilst magnetic fields are used to bend and focus beams of charged particles at high energies, electrostatic fields find application in low energy beam lines. They are used to deliver (anti)proton and ion beams at keV beam energies from a storage ring to an experiment, such as an ion trap. At these low energies, small field imperfections or misalignments lead to unwanted signals and this requires a very careful design of these beam optics using 3D field simulations.
Learning in the virtual world
Scene from Star Wars IV – A New Hope: R2-D2 delivers a holographic message from Princess Leia to Luke Skywalker and Obi-Wan Kenobi in which she asks the Jedi master for his help.
We cannot match the level of sophistication of R2-D2, but researchers are using machine-learning techniques to optimise the control of particle accelerators and artificial intelligence for data analysis.
Demonstration: This exercise uses techniques that are very close to R2’s hologram to help pupils understand electromagnetism better.
My colleagues at the Cockcroft Institute have developed acceleratAR, an app for mobile phones and tablets, which uses augmented reality to demonstrate the ways in which charged particles move through electromagnetic fields.
Your students can build their own accelerator by printing out the cubes from the website www.acceleratar.uk The app can be downloaded for free from Google Play.
Members of the galactic Empire, learning how to design accelerators using acceleratAR.
Within a real accelerator, particles gain energy as they pass through radiofrequency cavities. They are steered by dipole magnets and focused by quadrupole magnets.
Within acceleratAR, each of these components is represented by a paper cube. Your students can create the cubes and place them on a table and view them through the acceleratAR app running on a smartphone or iPad, to bring an ion source, RF cavity and magnets to life.
In this way they will get hands-on experience of the effects that certain magnets have on a charged particle beam, what happens if one changes their orientation or relative distance, and understand how complex optimization is required to transport a beam from an ion source to a distant experiment.
Questions for the students to encourage further discussion include:
- What happens if you accelerate the beam coming from the ion source in the RF cavity; how does it affect motion through a dipole magnet?
- Using several dipole magnets, can you control the beam well enough to send it around a real obstacle course?
- What is the difference between a dipole and a quadrupole magnet on the beam motion?
- A quadrupole focuses the beam in one transverse plane whilst it defocuses the beam in the other plane. Can you use two quadrupoles in combination to achieve an overall beam focusing?
Scene from Star Wars: “Travelling through hyperspace ain’t like dusting crops, boy! Without precise calculations we could fly right through a star or bounce too close to a supernova, and that’d end your trip real quick, wouldn’t it?” said Han Solo to Luke Skywalker in Star Wars IV, A New Hope.
Demonstration: The sudden deceleration experienced by space ships such as the iconic Millennium Falcon returning from hyperspace could be disastrous for inexperienced pilots.
To explore this challenge, we invite pupils to drop an egg onto the floor and see what happens – (if you cannot do this experiment outside, then an inflatable children’s paddling pool is an ideal landing zone and contains the fragments efficiently.)
We then give them a learning challenge: Can they manage to drop an egg from a height of around 4 meters and land it safely on the floor without breaking it? To achieve this, we only give them some simple (usually recyclable) materials:
- plastic bag
- clear sticky tape.
The rest is down to their creativity! They form small teams of 2-3 pupils and build protective containers, parachutes and come up with many other ways that will keep their egg intact. All groups record their final design on a planning sheet before building their prototypes. To stimulate interaction with other groups, each group can be given a printable prediction sheet. As each group shows their design concept to the class, other groups record each idea on the form and predict whether it will protect an egg or not.
Once all groups have presented their ideas, each group is given a raw egg to test out their design concept. Students love to decorate their eggs with Sharpies and this encourages creativity, ownership and sense of competition.
Finally, everyone gets together with their prototypes, eggs, and recording sheets and keeps a log of which designs have worked and whether their predictions were correct.
Scientists at the Quantum Systems and Advanced Accelerator Research (QUASAR) Group are working on a particle decelerator called ELENA (Extra Low Energy Ring for Antiprotons). In ELENA, beams of antiprotons travelling at close to the speed of light have to be brought to a stop so that physicists can investigate their properties in unprecedented detail. This experiment aims to help understand why there is an asymmetry between matter and antimatter in the universe.
Impact of the Event
- We have run the event with mixed classes, girls-only classes, schools with a low and a high uptake of science. The engagement of the pupils has consistently been exceptional.
- Participants significantly improved their understanding of electromagnetism and ways to control charged particles.
- The Physics of Star Wars events have had global media coverage, bringing the science and technology of the famous films into the classroom and explaining the science and technology of particle accelerators at the same time.
- The demonstrations and science content can be easily adapted to different year groups and adjusted to various class sizes – small groups benefit from giving all pupils the opportunity to gain hands-on experience, whilst larger groups are shown the demonstrations and are then engaged in discussions.
- As various scientific disciplines are needed to build and operate particle accelerators, the science discussion usually engage the entire class, rather than “only” students who most enjoy physics or computing or biology.
- A significant proportion of the students said that the event had made them consider a career in STEM.
- All of the students agreed – either a little or completely – that they would love to do an activity like that again.
- The majority of students felt that they had gained new skills and knowledge from the event.
- Many of the students stated that they would be interested in learning more about the topics covered in the event.
- Most of the students were able to state some of the things that researchers at CERN were doing and also able to correctly link particle accelerators to the medical industry.
- The majority of students were able to see how physics is everywhere in their lives, from craft, art and DT to crossing the road and doing sports as well as understanding the universe better.
Many other exciting developments, including antimatter research, novel plasma accelerating techniques and upgrades to the world’s largest particle accelerator, the Large Hadron Collider, have also been showcased at our events, which have proven popular with pupils and teachers alike.
Master Yoda also said to Count Dooku “This is just the beginning”. This is no doubt true in the case of accelerator science as well. Many more researchers and engineers will be needed in the future.
I hope that these suggestions for science lessons with a Star Wars spin will prompt you to find exciting new ways to engage your pupils with this emerging area of science discovery.
You can download a leaflet which was given to all participants and which contains many additional ideas via the following link: https://www.liverpool.ac.uk/quasar/dissemination/leaflets/
Additional films with suggestions for demo experiments can be viewed on the QUASAR Group’s YouTube channel: https://bit.ly/3aBTEQM
Professor Carsten P Welsch is Head of the Department of Physics at the University of Liverpool, Head of the Liverpool Accelerator Physics Group at the Cockcroft Institute in Daresbury and Head of the QUASAR group.