1 The power of water
The ways in which human activities interact with the water cycle can have devastating consequences for all forms of life. These range from the very large scale - for example, the effects of the movement of large volumes of water in a tsunami - to the molecular scale and the ability of water to dissolve solids, such as agricultural fertilisers (Figure 1).
Figure 1 (a) A tsunami wave; (b) a bag of agricultural fertiliser; (c) white crystals of the fertiliser sodium nitrate dissolving in a beaker of water. The image in (b) is a still taken from the video sequence Elements and Compounds which you will watch in Activity 1. It shows a bag of Chilean nitrate of soda which is sodium nitrate
Much of this course is devoted to exploring the smallest water particle - a water molecule - what it is and how it gives rise to the particular properties of water. You will be introduced to the use of powers of ten and scientific notation, which give a convenient way of expressing both very large and very small numbers. There is a video sequence to watch during your study of this course.