Have you ever wondered how scientists know when the population of a species is increasing or decreasing? Do they go out and count every single one to see how many there are? Or is there an easier way to do it?
If you look at the label of any food, you will probably find that it lists the Calorie content. Calories tell us how much energy you will get by consuming the food. How do scientists measure that energy?
One of the main things that we use for identifying clastic sedimentary rocks is grain size, the size of the pieces. Rocks that have been deposited by water or wind tend to be very well sorted, with all of the pieces being pretty much the same size. How does that happen?
In looking at the food web, we are trying to see how energy is transferred from one living thing to another. As part of that study, we need to be able to measure that energy. Luckily that involves something that you are probably very familiar with.