Quark Puzzle

Quark puzzle pieces
Short Description

Build particle systems from quarks using this quark puzzle.

Post date
10/03/2023 - 08:19
Tags
Elementary Particles
Standard Model
Author
CERN PER team
Activity Type
Hands-on
CERN Topic
Particles & particle systems
Curriculum Topic
Charges
Particles & particles systems

Description

Quarks are fundamental particles in the Standard Model of particle physics. They make up protons, neutrons and other exotic particles such as pions and kaons – but they are never found alone, always forming groups of two or three. This activity invites learners to discover the rules of quark combinations using a puzzle. Each puzzle piece represents a type of quark or antiquark, labelled with its electric and colour charge.

By physically combining the pieces, learners can build particle systems, understand charge conservation and explore the concept of colour neutrality. To find out more about CERN’s research in particle physics click here.

Page Overview

  1. 3D Puzzle Version
  2. 2D Puzzle Version

3D Puzzle Version

Material List

Instructions

3D-print the puzzle pieces. Students use these pieces to discover the rules that govern how quarks combine into composite particles. Each piece represents a quark or antiquark and is labelled with:

  • A flavour (e.g. up, down, anti-up, anti-down)
  • An electric charge (e.g. +2/3, -1/3)
  • A colour charge (e.g. red, green, blue, or anti-colours)

The shapes of the puzzle pieces guide students toward valid combinations:

  • Baryons are built from three quarks forming a cube
  • Mesons are built from one quark and one antiquark, forming a double pyramid

Using the worksheets provided, students complete guided tasks such as:

  • Building protons, neutrons, anti-protons, anti-neutrons,and pions
  • Recording the electric and colour charges of their combinations
  • Using evidence and reasoning to evaluate scientific claims (e.g. “Can a neutron have a charge of +1?”)
  • Comparing the puzzle model to real particle systems, and identifying its limitations

An introductory mission briefing challenges students to discover the rules of quark behaviour through trial and error.

2D Puzzle Version

Material List

In addition to the paper version, we also provide a 3D printable version of these 2D puzzle pieces.

Instructions

The 2D puzzle uses paper-printed or 3D-printed flat quark pieces with visible labels. The striped designs helps learners distinguish between colour and anti-colour charges.

  • Combine pieces to form baryons and mesons, following the same charge rules as the 3D version
  • Explore which combinations are valid and record findings using the same worksheets as the 3D version

Explanation

Quarks are elementary particles that make up protons, neutrons, and many other composite particles. They cannot exist on their own and always form groups called particle systems.

There are two main types of particle systems explored in this activity:

  • Baryons: Made of three quarks or three antiquarks
  • Mesons: Made of one quark and one antiquark

Each quark has two important properties:

  • Electric charge: Either +2/3 or -1/3. The total electric charge of a valid particle system must always be a whole number (e.g. -1, 0, +1)
  • Colour charge: Either red, green, or blue (or anti-red, anti-green, anti-blue for antiquarks). A valid particle system must always be colour neutral

This rule of colour neutrality means:

  • In baryons: one red, one green, and one blue quark combine to make white
  • In mesons: one colour and its corresponding anti-colour (e.g. red + anti-red) cancel out

These rules are inspired by the Standard Model of particle physics and help learners model how quarks behave in real experiments, even if the puzzle pieces themselves are only a simplified version of reality.

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