Motion, forces and energy
Physical quantities and measurement techniques
Units of measurement are are used to represent physical quantities like length, weight and other values. Units can be imperial or metric and can be converted by conversion factors.
Motion
The movement of objects can be described using motion graphs and numerical values. These are both used to help in the design of faster and more efficient vehicles.
Mass and weight
Mass聽is a measure of the quantity of matter in an object at rest relative to the observer.聽Weight聽is a gravitational force on an object that has mass.
Density
Density describes how closely packed the particles are in a solid, liquid or gas. Matter is made up of small particles called atoms. Atoms can exist on their own or as molecules.
Forces
Forces are responsible for changing the motion of objects. If more than one force is present, the shape of an object can also be changed.
Momentum
Momentum can be thought of as a combination of mass and velocity. Momentum helps explain some of the most important interactions in nature.
Energy, work and power
Energy is a key principle in physics. The rate at which energy is transferred is called power, the amount of energy that is transferred is called efficiency.
Pressure
Every living thing on Earth is in balance with the pressure of the air or water around it. Pressure helps blood to move around the body and allows organisms to breathe.
Forces podcast
Learn all about forces for your IGCSE physics exams, with scientists James Stewart and Ellie Hurer.
Energy podcast
Learn all about energy for your IGCSE physics exam with this podcast.
Video playlist
Brian Cox on the speed equation. Video
Professor Brian Cox gives an introduction to speed and the equation used to calculate it.
Relationship between planet size and gravitational field strength. Video
Space, the Moon landing and different planets are used to discuss gravity.
Density calculation. Video
Jonny Nelson explains density with a Physics practical experiment.
What is Hooke's Law? Video
An explanation of Hooke鈥檚 Law, using a spring as the example.
A demonstration of friction. Video
This short video gives a demonstration of friction.
Types of energy and how it's stored. Video
Jonny Nelson explores the different types of energy stores in this in-depth video.