Allow about 10 mins

This section can be studied at home or school. In total it should take up to 1 hour.

Course requirements

As part of the blended course, this topic is designed to be studied after first doing the face-to-face session Ener1 – Energy Stores and models.

If you missed this face-to-face session, you could catch up on some of the missed ideas by watching the following videos from the IOP domains series:

Building energy calculations from the ground up (11-16) - part of the IOP Domains CPD programme

Introducing energy calculations - part of the IOP Domains CPD programme

Energy calculations in action - part of the IOP Domains CPD programme

Overview

In the first module we looked at identify energy stores, and how to describe what is happening as one empties and one fills. One of the key aims for doing energy analysis is to enable to us to do calculations – how high, how fast, how stretched, how hot? Over time we will expect our students to make progress in what they are able to do by making energy calculations. The table below gives an idea of how the level of challenge might increase.

Four of the energy stores lend themselves to comparatively simple calculations. The following are used at KS4 that link physical properties to the store of energy – kinetic, gravitational, thermal and elastic. These each have single equations that can be used to determine the store of energy. At KS5 students will also calculate the electric store of energy when charges are moving in electric fields.

So, why are students required to think about other energy stores if they are not required to perform calculations? The answer is that they will be able to make statements about how those energy stores have changed, even if they cannot then link that to another physical change. For example, you could ask a question about how much energy it takes to climb Everest. The change to the gravitational store of energy as you climb   is relatively easy. Students should be able to identify that this has come from a corresponding decrease in the chemical store of energy of the climber. Even though they are not going to be able to work what the chemical store of energy is in the climber or in a Mars Bar, students should be able to say how much it has changed by, or how many Mars Bars you need to eat to climb Everest.

As well as calculating the energy in these stores (and the energy changes), we will consider the idea of work done.

The energy topic involves a lot of equations for students to recall and apply. Some of them seem to appear by magic. In this section, we explore the four equations associated with the physical manipulation of objects and try to explain what the equations are, when to use them, where they come from, and look at the equation being used in an exemplar question. You do not need to be able to derive each one, but many students and teachers ask, so it is useful to see how everything connects.

In the Electricity and Magnetism module, we look at both energy (7.3 - Energy calculations and mains electricity) and power calculations (7.2 - Power calculations) involving electricity. 

In section 3 we will consider the energy in thermal store.

Progression

Key terminology

Work done is the measure of energy transferred when a force moves an object through a distance (in the direction of that force).

Activities