Before you read this, it would be useful to read post 16.8. Post 16.8 is a story about a biologist who investigated the rabbit population on a farm. He counted the number of rabbits every year for 5 years. When he plotted a graph of the number of rabbits against time, he got a straight… Continue reading 16.42 Keep it simple

“Physics World” is a magazine for members of the UK’s Institute of Physics. The September 2016 issue contained a very interesting letter about science teaching in schools, and especially about encouraging girls to study physics. However, the writer was concerned that many of her pupils can’t tell the difference between physics, chemistry and biology. They’re… Continue reading 16.41 Physics, chemistry and biology

Before you read this, I suggest that you read posts 16.27, 16.29, 16.30, 16.33 and 16.39. If you find this blog too difficult or tedious to read in detail, just notice that some complicated ions consist of several atoms covalently bonded, as in a molecule (see post 16.30), but with one or more extra electrons… Continue reading 16.40 Complicated ions

Before you read this, I suggest that you read posts 16.25, 16.27, 16.29 and 16.37 In a previous post, we have seen how atoms of different elements can combine to form compounds (post 16.30). So far we have considered only one type of compound, in which atoms of different elements are joined together to make… Continue reading 16.39 Ions

Before you read this, I suggest you read posts 16.34, 16.35 and 16.37. In post 16.34 entropy was introduced as the quantity of heat flowing into an object divided by its temperature (on the Kelvin scale). This definition leads to the idea that the entropy of a closed system tends to increase spontaneously. The idea… Continue reading 16.38 Entropy and disorder