Has anyone ever recommended something to cure a minor ailment, or something to improve your health, because “it worked for me”? This “something” could be an expensive commercial product (like some dietary supplements), aromatherapy, a copper bracelet, a magnetic bracelet, a change in diet or an exercise regime. The problem is that all of these… Continue reading 16.46 The placebo effect

Before you read this, I suggest you read posts 16.44, 16.30 and 16.27. The density of something is the mass of a sample of it divided by the volume of the sample (post 16.44). So, we might expect that, when we heat a solid, its density will increase; this is because when we heat a… Continue reading 16.45 Water

Which has the greatest mass 1 kg of steel or 1 kg of wood? (If you’re not sure what “mass” means see posts 16.12 and 16.13.) I hope that you immediately realised that both have the same mass of 1 kg. But we all believe that steel is “heavier” (it has a higher mass) than… Continue reading 16.44 Density

It would be useful to read posts 16.8 and 16.42 before you read this. Two previous posts (16.8 and 16.42) were about a biologist who developed a simple model to predict the number of rabbits on a farm. It took him 5 years to collect the data to develop his model. He then used it… Continue reading 16.43 Test before you predict