Before you read this, I suggest that you read posts 16.2, 16.21 and 16.27 We can measure the energy of electrons in atoms from the wavelengths at which elements (see post 16.27) absorb or emit light. The Danish physicist Niels Bohr explained these results using the quantum theory (see post 16.2) in which electrons are… Continue reading 16.29 Electrons in atoms

Before you read this, I suggest that you read posts 16.24 and 16.26. In this post I want to explore how we make decisions based on experimental results. Suppose two groups of rats, are identical in all respects, eat the same diet and live in identical conditions. However, one group is given a dietary supplement… Continue reading 16.28 Significant differences

I suggest that you read post 16.25 on electrical charge before you read this. The ancient Greek philosopher Democritus believed that you couldn’t keep breaking stuff into smaller and smaller bits – there must be a limit. He called these smallest bits of stuff atoms. I’m not convinced by the logic of his argument (see… Continue reading 16.27 Atoms

Before you read this, I suggest you read post 16.24. If you repeat an experiment several times, you will get slightly different results because of random effects beyond your control. For example, if you measure the temperature at which a liquid boils, you may get slightly different results because of changes in atmospheric pressure –… Continue reading 16.26 Normal distribution