148 Pages

## Overview

P1 Part 1 covers kinetic theory and transfers of energy. There is a particular focus on heat transfers and calculations of efficienty and the energy and cost of using electrical appliances.

#### P1.1 The Transfer of energy by heating processes

Energy can be transferred from one place to another by work or by heating processes. We need to know how this energy is transferred and which heating processes are most important in a particular situation.

#### P1.2 Energy and Efficiency

Appliances transfer energy but they rarely transfer all of the energy to the place we want. We need to know the efficiency of appliances so that we can choose between them, including how cost effective they are, and try to improve them.

#### P1.3 The usefulness of electrical appliances

We often use electrical appliances because they transfer energy at the flick of a switch. We can calculate how much energy is transferred by an appliance and how much the appliance costs to run.

## Lesson Summaries

Specification Reference Summary of Specification contents. Learning Outcomes

## P1.1.2 Kinetic theory

### P1 Lesson 1 Kinetic theory and changes of state.

a The use of kinetic theory to explain the different states of matter. Draw simple diagrams to model the difference between solids, liquids and gases.
b The particles of solids, liquids and gases have different amounts of energy. Describe the states of matter in terms of the energy of their particles.

## P1.2.1 Energy transfers and efficiency

### P1 Lesson 2 Energy transfers, Sankey diagrams and Efficiency.

a Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed. Describe the energy transfers and the main energy wastages that occur in a range of situations or appliances.
b When energy is transferred only part of it may be usefully transferred, the rest is ‘wasted’. Interpret and draw a Sankey diagram.
c Wasted energy is eventually transferred to the surroundings, which become warmer. The wasted energy it becomes increasingly spread out and so becomes less useful. Understand the concept of efficiency and why efficiency can never be greater than 100%.
d To calculate the efficiency of a device using: Use the equation to calculate efficiency as a decimal or percentage.

## P1.1.3 Energy transfer by heating

### P1 Lesson 3&4 Conduction and Convection

a The transfer of energy by conduction and convection involves particles, and how this transfer takes place. Understand in simple terms how the arrangement and movement of particles determine whether material is a conductor or insulator.
Understand the role of free electrons in conduction through a metal.
Use the idea of particles moving apart to make a fluid less dense and to explain simple applications of convection.

### P1 Lesson 5 Evaporation and Condensation

a The transfer of energy by evaporation and condensation involves particles, and how this transfer takes place. Explain evaporation and the cooling effect this causes using the kinetic theory
b The factors that affect the rate of evaporation and condensation.

### P1 Lesson 6&7 Factors that affect heat transfer

c The rate at which an object transfers energy by heating depends on a number of factors. Know that the rate at which an object transfers energy by heating depends on: surface area and volume, the material from which the object is made, the nature of the surface with which the object is in contact, the temperature difference between the object and its surroundings.
d The bigger the temperature difference between an object and its surroundings, the faster the rate at which energy is transferred by heating. Be able to explain the design of devices in terms of energy transfer, eg cooling fins.
Be able to explain animal adaptations in terms of energy transfer, eg relative ear size of animals in cold and warm climates.

### P1 Lesson 8&9 Emission of Infra Red radiation

b The hotter an object is the more infrared radiation it radiates in a given time. Understand what infrared radiation is.
c Dark, matt surfaces are good emitters of infrared radiation. know the factors which affect the rate at which an object radiates infrared radiation
d Light, shiny surfaces are poor emitters of infrared radiation.

### P1 Lesson 10 Absorption of Infra Red radiation

c Dark, matt surfaces are good absorbers of infrared radiation. Know the factors which affect the rate at which an object absorbs infrared radiation.
d Light, shiny surfaces are poor absorbers of infrared radiation.

## P1.1.4 Heating and insulating buildings

### P1 Lesson 11&12 Specific Heat Capacity

d The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius. E = m × c × ө Understand the meaning of specific heat capacity.
Evaluate different materials according to their specific heat capacities, eg water, which has a very high specific heat capacity, oil filled radiators and electric storage heaters containing concrete.

### P1 Lesson 13 U-Values

a U-values measure how effective a material is as an insulator. Know what a U-value is and what it tells us about the material as an insulator.
b The lower the U-value, the better the material is as an insulator. Be able to evaluate the effectiveness of different types of material used for insulation, including U-values and economic factors including payback time.
c Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water. Be able to evaluate the efficiency and cost effectiveness of methods used to reduce ‘energy consumption’.

## P1.3.1 Transferring electrical energy

### P1 Lesson 14&15 The transfer of electrical energy

a Examples of energy transfers that everyday electrical appliances are designed to bring about. Understand the energy transfers that occur in electrical appliances.
b The amount of energy an appliance transfers depends on how long the appliance is switched on and its power. Use the equation to calculate the energy transferred from the mains to an electrical appliance, either in joules or kilowatt-hours.
c To calculate the amount of energy transferred from the mains using the equation: E = P × t Calculate the cost of using individual appliances and also to interpret electricity meter readings to calculate total cost over a period of time.
d To calculate the cost of mains electricity given the cost per kilowatt-hour (kWh)

## Summary of P1.1, 1.2 and 1.3

### P1 Lesson 16 Summary

Summary of sections P1.1, P1.2 and P1.3