Matter and Energy Transformations
MYP Unit Framework
Key Concept: CHANGE Related Concepts: Energy, Transformation, Evidence Global Context: Scientific and Technical Innovation (How can we use our understanding of matter and energy to solve problems?) Statement of Inquiry: Matter and energy transform in predictable ways that can be measured, modelled, and applied.
Inquiry Questions
| Type | Question |
|---|---|
| Factual | What are the three states of matter? What is the difference between a physical and a chemical change? |
| Conceptual | Why do states of matter change at specific temperatures? How is energy transferred between objects? |
| Debatable | Can we ever create or destroy matter or energy — or are we just transforming them? Should we rely on technology that transforms energy (e.g., nuclear power) even with risks? |
ATL Skills
- Thinking: Distinguish between physical and chemical changes; apply conservation laws
- Research: Design and conduct experiments; record and interpret observations
- Communication: Write lab reports; draw particle diagrams; present findings
- Self-Management: Work safely with laboratory equipment; follow experimental procedures
1. States of Matter
The Three States
- Solid: Fixed shape and volume. Particles are closely packed in a regular arrangement and vibrate in place.
- Liquid: Fixed volume but takes the shape of its container. Particles are close together but can move past each other.
- Gas: No fixed shape or volume. Particles are far apart and move freely at high speed.
Particle Theory
All matter is made of tiny particles (atoms, molecules, or ions) that are in constant motion. Temperature is a measure of the average kinetic energy of particles.
Changes of State
- Melting: Solid to liquid (energy absorbed)
- Freezing: Liquid to solid (energy released)
- Evaporation/Boiling: Liquid to gas (energy absorbed)
- Condensation: Gas to liquid (energy released)
- Sublimation: Solid to gas directly (energy absorbed)
- Deposition: Gas to solid directly (energy released)
2. Physical and Chemical Changes
Physical Changes
A physical change alters the form or appearance of matter but does NOT change its chemical composition.
Examples: Melting ice, dissolving sugar, cutting paper, boiling water, mixing sand and salt.
Characteristics: No new substance formed; usually reversible; conservation of mass.
Chemical Changes
A chemical change produces one or more NEW substances with different properties from the original.
Examples: Burning wood, rusting iron, cooking an egg, baking a cake, photosynthesis.
Signs of Chemical Change:
- Change in colour
- Production of gas (bubbles)
- Formation of a precipitate (solid from solution)
- Change in temperature (exothermic or endothermic)
- Production of light or sound
- Change in odour
Chemical Equations
Chemical reactions are represented by equations. Reactants → Products.
Example: 2H<sub>2</sub> + O<sub>2</sub> → 2H<sub>2</sub>O (hydrogen + oxygen → water)
The equation is BALANCED when there are equal numbers of each atom on both sides.
3. Energy Transfers
Forms of Energy
- Kinetic Energy: Energy of motion
- Thermal (Heat) Energy: Energy due to temperature
- Chemical Energy: Stored in chemical bonds
- Electrical Energy: Energy from moving electrons
- Light (Radiant) Energy: Electromagnetic radiation
- Sound Energy: Energy from vibrations
- Nuclear Energy: Stored in atomic nuclei
- Elastic Potential Energy: Stored in stretched or compressed materials
- Gravitational Potential Energy: Stored due to height
Conservation of Energy
The Law of Conservation of Energy states: Energy cannot be created or destroyed — it can only be transformed from one form to another or transferred between objects.
Example: A ball held at a height has gravitational potential energy. When dropped, this converts to kinetic energy. When it hits the ground, kinetic energy transforms into sound and thermal energy.
Energy Efficiency
Not all energy is usefully transformed. Some is always 'wasted' (usually as heat).
Efficiency = Useful energy output / Total energy input x 100%
Heat Transfer
- Conduction: Transfer of heat through direct contact (solids are good conductors)
- Convection: Transfer of heat through fluid movement (liquids and gases)
- Radiation: Transfer of heat through electromagnetic waves (does not require a medium)
4. Measuring and Modelling
Temperature and Heat
- Temperature: A measure of the average kinetic energy of particles (measured in degrees Celsius or Kelvin)
- Heat: The total thermal energy transferred between objects (measured in Joules)
Specific Heat Capacity
The amount of energy required to raise the temperature of 1 kg of a substance by 1 degree Celsius.
Formula: Q = mc(delta)T (where Q = thermal energy, m = mass, c = specific heat capacity, delta T = temperature change)
Particle Models
Scientists use particle models to explain observations:
- Density: More particles in a given volume = higher density
- Pressure in gases: Particles collide with container walls — more frequent/harder collisions = higher pressure
- Expansion: Heating increases particle movement, so substances expand
5. Practical Investigations
Investigation 1: Melting and Freezing
Investigate the melting point of a substance (e.g., ice, wax). Record temperature at regular intervals as the substance is heated. Plot a cooling curve.
Investigation 2: Chemical vs. Physical Changes
Observe several changes (dissolving, burning, mixing, heating). Classify each as physical or chemical. Justify your classification with evidence.
Investigation 3: Insulation
Test different materials as thermal insulators. Measure how quickly hot water cools when wrapped in different materials. Evaluate which material is the best insulator.
Investigation 4: Energy in Food
Burn a food sample (e.g., a peanut or cracker) under a container of water. Measure the temperature change of the water. Calculate the energy released per gram of food.
Safety Notes
- Wear safety goggles when heating substances or burning materials
- Use tongs for hot objects
- Work in a well-ventilated area
- Never taste or touch chemicals
- Dispose of materials according to instructions
Summative Assessment
Task: Experimental investigation with written report (800-1000 words).
Criteria:
- A: Knowing and Understanding — Explain concepts of matter and energy transformation
- B: Inquiring and Designing — Design a method to investigate a question
- C: Processing and Evaluating — Collect, process, and evaluate data; discuss limitations
- D: Reflecting on the Impacts of Science — Discuss real-world applications
Option 1: Investigate factors affecting the rate of dissolving (temperature, particle size, stirring). Explain using particle theory.
Option 2: Determine which material is the best thermal insulator. Design fair testing and explain results using conduction concepts.
Option 3: Investigate the energy content of different foods. Compare results with packaged nutrition information and discuss discrepancies.
Formative Assessment
- Particle diagrams: draw the arrangement of particles in solids, liquids, and gases
- Sorting activity: classify changes as physical or chemical with justification
- Energy transformation chains: draw and label energy transformations (e.g., from a power plant to a light bulb)
- Laboratory skills checklist: using thermometers, Bunsen burners, measuring cylinders
- Calculation practice: specific heat capacity, efficiency
Interdisciplinary Connections
- Mathematics: Calculating efficiency; interpreting graphs (cooling curves); specific heat capacity calculations
- Geography: Energy resources — fossil fuels, renewable energy, energy distribution
- Design: Designing insulation for a building or a container
- Health: Energy in food; metabolism; the importance of thermal regulation in the human body
Service as Action
- Energy Audit: Conduct an energy audit of your school or home. Identify areas of energy waste and recommend improvements.
- Insulation Project: Collect materials for insulation (e.g., blankets, old clothing) and distribute them to a local shelter or community organisation.
IB Learner Profile
- Inquirers: Ask questions about the physical world and design experiments to test ideas
- Knowledgeable: Understand the properties and behaviour of matter and energy
- Thinkers: Apply particle theory and conservation laws to explain observations
- Caring: Consider the environmental impact of energy use
Self-Test
- Describe the arrangement and movement of particles in solids, liquids, and gases.
- What is the difference between a physical change and a chemical change? Give an example of each.
- List FOUR signs that a chemical change has occurred.
- State the Law of Conservation of Energy.
- List FIVE forms of energy and give an example of each.
- Explain the difference between conduction, convection, and radiation.
- What does specific heat capacity measure?
- Calculate the efficiency of a device that uses 500 J of energy to produce 350 J of useful output.
- Draw particle diagrams for melting and boiling.
- Explain why a metal spoon feels colder than a wooden spoon at the same temperature.
This unit aligns with IB MYP Sciences guide, developed for Year 3 (Class 8) students.
