### Video lessons on equations and graphs for physics

The video lessons on equations and graphs described below run through some of the mathematical and graphical ideas students have to grasp. The shortest of these on the Inverse Square Law is given as an example at the bottom of the page.

**Exponential change ****15 minutes**

Exponential decay commonly occurs in many branches of physics. The video below explains the idea with a simple to understand, practical demonstration of water flowing out of a can and then moves on to the detail of two applications within the 16 to 19 physics syllabus.

The first is radioactive decay, half life and the decay constant using an accurate animation of a decay sequence.

The second is the discharge of a capacitor and the time constant using results from a practical demonstration.

**The inverse square Law 3m**

An explanation of the inverse square law which can be applied to light heat and gravity explained using a butter gun.

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**Rearranging equations 4m (In GCSE, 14 to 16 years, collection also suitable for A level introduction)**

Suggesting a few basic ideas and techniques for rearranging some of the equations common in physics.

**Linear graphs 5m (In GCSE, 14 to 16 years, collection also suitable for A level introduction)**

Graphs are an important visual means of proving and displaying numerical connections. Linear or straight line graphs are produced for example when plotting current against PD for a fixed resistance, distance against time for a given speed and the energy of a photon plotted against frequency.

The tutorial below aims to remind you how to draw a good accurate graph and how the line is changed as the constants in the relationship change.

**Power, log, exponential and trig graphs 10m**

This video lesson runs through best way to draw a curved graph by hand and then illustrates the shape of the most common graphs used in Maths and Physics based on the equations Y= X squared (parabolic), 1/X, root X, e to the power X (exponential), log X, sin X, cos X, tan X.

**Revising 6m (In GCSE, 14 to 16 years, collection also suitable for A level introduction)**

This video lessons runs through some ideas and techniques for efficient revision, including use of the published syllabus, time management, making revision active, using a variety of resources, using past papers and mark schemes and on taking care of yourself.