Ratio and proportion

Why is the modern piano tuned using an equal tempered scale and what has this got to do with logarithms?

When a mixture of gases burn, will the volume change?

Ever wondered what it would be like to vaporise a diamond? Find out inside...

A brief introduction to PCR and restriction mapping, with relevant calculations...

If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?

A ladder 3m long rests against a wall with one end a short distance from its base. Between the wall and the base of a ladder is a garden storage box 1m tall and 1m high. What is the maximum distance up the wall which the ladder can reach?

What does the empirical formula of this mixture of iron oxides tell you about its consituents?

Do each of these scenarios allow you fully to deduce the required facts about the reactants?

The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?

A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns around and heads back to the starting point where he meets the runner who is just finishing his first circuit. Find the ratio of their speeds.