Fundamental particles. Hadrons.

General physics

Quarks: Fundamental Particles — Physics Lesson

🎯 Learning Objectives

Learning Objectives

Understand that a quark is a fundamental particle and identify the six flavours: up, down, strange, charm, top and bottom
Recall and use the charge of each flavour of quark and understand that antiquarks have opposite charges
Recognize that protons and neutrons are not fundamental particles and describe them in terms of quark composition
Understand that hadrons can be baryons (three quarks) or mesons (one quark and one antiquark)

🗣️ Language Objectives

Language Objectives

Use scientific vocabulary related to particle physics accurately
Explain quark composition using appropriate terminology
Describe particle interactions using precise language
Communicate scientific concepts clearly in English

📚 Key Terms

Key Terms

English	Russian (Русский)	Kazakh (Қазақша)
Quark	Кварк	Кварк
Fundamental particle	Фундаментальная частица	Іргелі бөлшек
Hadron	Адрон	Адрон
Baryon	Барион	Барион
Meson	Мезон	Мезон
Antiquark	Антикварк	Антикварк
Flavour	Аромат (тип)	Дәм (түр)
Electric charge	Электрический заряд	Электр заряды

🎴 Study Cards

Quark Study Cards

Up Quark (u)

Charge: +2/3

Symbol: u

Found in: Protons and neutrons

Down Quark (d)

Charge: -1/3

Symbol: d

Found in: Protons and neutrons

Strange Quark (s)

Charge: -1/3

Symbol: s

Found in: Strange hadrons

Charm Quark (c)

Charge: +2/3

Symbol: c

Found in: Charmed hadrons

Top Quark (t)

Charge: +2/3

Symbol: t

Found in: High-energy collisions

Bottom Quark (b)

Charge: -1/3

Symbol: b

Found in: Bottom hadrons

📖 Glossary

Glossary

Quark: A fundamental particle that combines to form hadrons. Quarks cannot exist alone in nature.

Translation

Russian: Кварк — фундаментальная частица, которая объединяется для образования адронов. Кварки не могут существовать в природе отдельно.
Kazakh: Кварк — адрондар түзу үшін бірігетін іргелі бөлшек. Кварктер табиғатта жеке өмір сүре алмайды.

Fundamental Particle: A particle that is not known to have any substructure and cannot be broken down into smaller components.

Translation

Russian: Фундаментальная частица — частица, которая не имеет известной внутренней структуры и не может быть разложена на более мелкие компоненты.
Kazakh: Іргелі бөлшек — ішкі құрылымы белгісіз және кішірек бөліктерге ыдырамайтын бөлшек.

Hadron: A composite particle made of quarks, including both baryons and mesons.

Translation

Russian: Адрон — составная частица, состоящая из кварков, включающая как барионы, так и мезоны.
Kazakh: Адрон — кварктардан тұратын құрама бөлшек, бариондар мен мезондарды қамтиды.

Baryon: A hadron composed of three quarks, such as protons and neutrons.

Translation

Russian: Барион — адрон, состоящий из трех кварков, например протоны и нейтроны.
Kazakh: Барион — протон мен нейтрон сияқты үш кварктан тұратын адрон.

Meson: A hadron composed of one quark and one antiquark.

Translation

Russian: Мезон — адрон, состоящий из одного кварка и одного антикварка.
Kazakh: Мезон — бір кварк пен бір антикварктан тұратын адрон.

🔬 Theory: Understanding Quarks

Theory: Understanding Quarks

What are Quarks?

are particles that are the of matter. Unlike , which can be broken down into smaller components, quarks are believed to be .

Translation

Kazakh: Кварктер заттың құрылыс блоктары болып табылатын іргелі бөлшектер. Кішірек бөліктерге ыдырайтын атомдардан айырмашылығы, кварктер бөлінбейтін деп саналады.

The Six Flavours of Quarks

There are six flavours (types) of quarks:

Up (u): Charge = +2/3
Down (d): Charge = -1/3
Strange (s): Charge = -1/3
Charm (c): Charge = +2/3
Top (t): Charge = +2/3
Bottom (b): Charge = -1/3

Translation

Kazakh: Кварктердің алты дәмі (түрі) бар: жоғарғы, төменгі, ерекше, сүйкімді, үстіңгі және төменгі кварктер. Әрқайсысының өзіндік электр заряды бар.

Antiquarks

Every quark has a corresponding antiquark with the opposite charge. For example, the up antiquark (ū) has a charge of -2/3.

Translation

Kazakh: Әрбір кварктың қарама-қарсы зарядтағы сәйкес антикваркі бар. Мысалы, жоғарғы антикварктың заряды -2/3.

Protons and Neutrons

and are NOT fundamental particles. They are particles made of quarks:

Proton: uud (two up quarks, one down quark)
Neutron: udd (one up quark, two down quarks)

Translation

Kazakh: Протондар мен нейтрондар іргелі бөлшектер ЕМЕС. Олар кварктардан тұратын құрама бөлшектер: протон — екі жоғарғы және бір төменгі кварктан, нейтрон — бір жоғарғы және екі төменгі кварктан тұрады.

Hadrons: Baryons and Mesons

A hadron is any particle made of quarks. There are two main types:

Baryons: Made of three quarks (like protons and neutrons)
Mesons: Made of one quark and one antiquark

Translation

Kazakh: Адрон — кварктардан жасалған кез келген бөлшек. Екі негізгі түрі бар: бариондар (үш кварктан) және мезондар (бір кварк пен бір антикварктан).

Practice Questions

1. Easy: How many flavours of quarks are there?

Answer

There are six flavours of quarks: up, down, strange, charm, top, and bottom.

2. Medium: What is the charge of an up antiquark?

Answer

The up antiquark has a charge of -2/3 (opposite to the up quark’s +2/3 charge).

3. Medium: Calculate the total charge of a proton using quark composition.

Answer

A proton consists of two up quarks (+2/3 each) and one down quark (-1/3).
Total charge = 2 × (+2/3) + 1 × (-1/3) = +4/3 — 1/3 = +3/3 = +1

4. Hard (Critical Thinking): Why can’t quarks exist alone in nature? What does this tell us about the fundamental forces?

Answer

Quarks cannot exist alone due to color confinement — a property of the strong nuclear force. As quarks are separated, the strong force between them increases (unlike other forces that weaken with distance). This suggests that the fundamental forces behave differently at different scales and that nature has mechanisms to ensure certain particles remain bound together.

🧠 Memory Exercises

Exercises on Memorizing Quark Terms

Exercise 1: Fill in the Blanks

1. The six flavours of quarks are: up, down, _______, charm, _______, and bottom.

2. A _______ consists of three quarks, while a _______ consists of one quark and one antiquark.

3. The charge of an up quark is _______, and the charge of a down quark is _______.

Answer

1. strange, top
2. baryon, meson
3. +2/3, -1/3

Exercise 2: Match the Pairs

Match each quark with its charge:

Up quark → ?
Down quark → ?
Strange quark → ?
Charm quark → ?

Charges: +2/3, -1/3, -1/3, +2/3

Answer

Up quark → +2/3
Down quark → -1/3
Strange quark → -1/3
Charm quark → +2/3

🎥 Educational Video

Understanding Quarks — Video Lesson

Additional Resources:

🧮 Worked Examples

Problem Solving Examples

Example 1: Determining Particle Composition

Problem: A particle has a charge of +1 and consists of three quarks. Two of the quarks are up quarks. What is the third quark?

Answer

Step-by-step solution:
1. We know the total charge is +1
2. We have two up quarks, each with charge +2/3
3. Charge from up quarks = 2 × (+2/3) = +4/3
4. Let x be the charge of the third quark
5. Total charge equation: +4/3 + x = +1
6. Solving: x = +1 — 4/3 = +3/3 — 4/3 = -1/3
7. The quark with charge -1/3 could be down, strange, or bottom
8. Since this describes a proton, the third quark is a down quark

Answer

Quick solution:
Two up quarks (+2/3 each) + one down quark (-1/3) = +4/3 — 1/3 = +1
The third quark is a down quark.

Example 2: Meson Composition

Problem: A meson has zero charge. If it contains a charm quark, what must the other particle be?

Answer

Detailed solution:
1. A meson consists of one quark and one antiquark
2. The meson has zero total charge
3. Charm quark has charge +2/3
4. For zero total charge: +2/3 + x = 0
5. Therefore: x = -2/3
6. The other particle must be an antiquark with charge -2/3
7. This is a charm antiquark (c̄)
8. The meson is composed of a charm quark and charm antiquark (cc̄)

Answer

Quick answer:
Charm quark (+2/3) + Charm antiquark (-2/3) = 0
The other particle is a charm antiquark.

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🔬 Investigation Activity

Interactive Simulation: Build an Atom

Use this simulation to explore how protons and neutrons are made of quarks:

Investigation Questions:

1. How does changing the number of protons affect the atom?

Answer

Changing the number of protons changes the element. Each element is defined by its number of protons (atomic number).

2. What happens to the charge when you add or remove electrons?

Answer

Adding electrons makes the atom negatively charged (anion), while removing electrons makes it positively charged (cation).

3. How do neutrons affect the atom’s properties?

Answer

Neutrons affect the atom’s mass but not its charge. Different numbers of neutrons create isotopes of the same element.

👥 Group Activity

Collaborative Learning: Quark Quiz

Work in pairs or groups to complete this interactive quiz about quarks:

Group Discussion Points:

Compare your answers with your partner
Discuss any disagreements and research the correct answers
Create your own quark-related questions to challenge other groups
Present one interesting fact about quarks to the class

📝 Individual Assessment

Structured Questions — Individual Work

Question 1: Analysis

A new particle is discovered with the following properties:

Total charge: +2
Contains three quarks
One quark is identified as a charm quark

a) Determine the possible combinations of the other two quarks. Show your calculations.

b) Explain why this particle would be classified as a baryon.

c) Discuss the stability of such a particle in nature.

Answer

a) Charm quark has charge +2/3. For total charge +2:
+2/3 + x + y = +2, so x + y = +4/3
Possible combinations: two up quarks (+2/3 each) = +4/3

b) It’s a baryon because it contains three quarks.

c) This particle would be unstable because it contains a heavy charm quark, which would decay quickly via the weak force.

Question 2: Synthesis

Design a hypothetical experiment to verify that protons contain quarks. Consider:

a) What type of collision would be needed?

b) What evidence would you look for?

c) How would you distinguish between fundamental and composite particles?

Answer

a) High-energy electron-proton collisions (deep inelastic scattering)

b) Evidence of point-like constituents inside protons, scattered electrons at various angles, jets of particles indicating quark fragmentation

c) Fundamental particles would show no internal structure, while composite particles would show evidence of constituents with fractional charges and specific angular distributions

Question 3: Evaluation

The quark model successfully explains many properties of hadrons, but quarks have never been observed in isolation. Evaluate the scientific validity of the quark model given this limitation.

Answer

The quark model remains scientifically valid because:
1. It makes accurate predictions about particle properties
2. Indirect evidence strongly supports quark existence
3. The model explains why quarks can’t be isolated (color confinement)
4. Many successful theories deal with unobservable entities
5. The model’s predictive power outweighs the limitation of direct observation

Question 4: Application

A scientist claims to have discovered a new meson with charge +2. Analyze this claim and explain whether such a particle could exist according to the quark model.

Answer

This is impossible. A meson consists of one quark and one antiquark. The maximum positive charge would be from an up quark (+2/3) and a down antiquark (+1/3), giving +1 total. No combination of one quark and one antiquark can produce a charge of +2. The claim violates the fundamental rules of the quark model.

Question 5: Critical Analysis

Compare and contrast the historical development of atomic theory with the current understanding of quarks. What parallels can you draw, and what does this suggest about the future of particle physics?

Answer

Parallels include: both theories explained previously unexplained phenomena, both proposed invisible constituents, both evolved through experimental evidence. The atomic theory progressed from indivisible atoms to complex internal structure. Similarly, quarks might have their own internal structure. This suggests particle physics will continue to discover deeper levels of reality, possibly through string theory or other approaches.

🔗 Additional Resources

Useful Links for Further Study

🤔 Lesson Reflection

Reflection Questions

Self-Assessment:

Rate your understanding (1-5 scale):

I can identify the six flavours of quarks: ⭐⭐⭐⭐⭐
I understand quark charges and their opposites: ⭐⭐⭐⭐⭐
I can explain proton and neutron composition: ⭐⭐⭐⭐⭐
I understand the difference between baryons and mesons: ⭐⭐⭐⭐⭐

Critical Thinking:

1. What was the most challenging concept in this lesson?

2. How does understanding quarks change your perspective on matter?

3. What questions do you still have about particle physics?

4. How might this knowledge be applied in future technology?

Language Learning:

1. Which scientific terms were new to you?

2. How confident are you in explaining quark concepts in English?

3. What vocabulary would you like to review?

Next Steps:

Based on your reflection, what topics would you like to explore further?

☐ Other fundamental particles (leptons, bosons)
☐ The Standard Model of particle physics
☐ Particle accelerators and detection methods
☐ Applications of particle physics in technology