Before you read this, I suggest you read posts 16.21 and 17.38. This post is very mathematical, so you might want to stop reading after the paragraph on “models” – if you decide to do this, it might be worth reading the final two paragraphs. A pendulum is an object, like that shown in the… Continue reading 18.6 The pendulum: a simple harmonic oscillator

Before you read this, I suggest you read posts 18.1 and 18.3. To calculate pH values, we need to understand more about the pH scale, for measuring acidity and alkalinity, that was in introduced in post 18.1. The definition of pH is that pH = – log10[H+]. In this definition, [H+] represents the molar concentration… Continue reading 18.5 Calculating pH values