Before you read this, I suggest you read post 16.13. In the previous post (post 16.49), we saw the difference between forces that stretch things and forces that act in the opposite direction to compress things. In this post we will think about forces that act in any direction. Let’s suppose we want to use… Continue reading 16.50 Direction of forces

Before you read this, I suggest you read posts 16.13, 16.20 and 16.21. Let’s think about a spring that is fixed at one end; when a force pulls it at the other end, it gets longer. When a spring is pulled, so that it gets longer, we say that it is in tension and the… Continue reading 16.49 Springs

Before you read this, I suggest you read posts 16.45 and 16.47. Why do we use soap to wash ourselves? Why don’t we just use water? If you’ve ever asked yourself these questions, you may have decided that using soap gets us cleaner. So why does soap get us cleaner? Not many people ask themselves… Continue reading 16.48 How does soap work?

The picture above shows how carbon, hydrogen and oxygen molecules combine to form a fat molecule; as expected each carbon atom forms 4 covalent bonds, each hydrogen atom forms 1 covalent bond and each oxygen atom forms 2 covalent bonds. (More information on covalent bonds and molecules is given in post 16.30.) The vertical bonds… Continue reading 16.47 Fats