and then there was all this physics happening that we don’t pay attention to. Most particularly, pay attention as to how we weigh the various stuff we are buying. There is a reason we have scales: we don’t want to trust that a pound is a pound if we can not see it is a pound. People are just not that good of a measuring device themselves. The act of measuring some property of a physical object is a very important part of studying it from the physical point of view. We do that measurement by using an instrument of some sort. The art of creating new measuring devices is called instrumentation, and it is one of the basic pieces of work done in the experimental side of physics.
Which brings me back to the market. How do you know that a particular potato has more potato in it than another potato? The concept of how much potato a given potato has is related to it’s mass. If you have more mass of potato in one potato than in another potato, then the first potato has more potato in it. See? I made an illustration to show how important it is to know if you have more or less of a potato.
Now, you might be wondering, what it this mass thing? Well, it is one of those irreducible concepts in physics that nobody can explain, but that anyone with a mass scale can measure. We usually use the letter m for mass. Unless, of course, if we have already used that letter before, in which case we would call it M. And if we have a lot of masses, we label them with numbers, or greek letters, like so
and before you know it, we will be writing equations like
Oops! I was getting carried away. Just notice that the m in that equation stands for mass. It is the most quoted equation in physics ever. I’m not going to explain it here. So now that you know that we don’t know either what mass really is, you can be satisfied that for practical purposes it does not matter. The fact that we can measure it can serve as it’s own definition and one does not have to worry about all that philosophy. And in everyday life, the mass of an object stays pretty constant, that is, until you combine it with other objects, or you take little pieces away from it. Now, I’ve been told that the only way to make sure that you can get a real cadre of blog followers is if you provide them with cooking recipes that you can try at home. I’ll call this one massed potatoes.
Ingredients: A couple of large potatoes, peeled. Plenty of water for boiling. Salt, pepper.
Preparation: Cut potatoes into small pieces. Boil the potatoes for about 40-60 15-20 minutes, until they start falling apart can be broken easily with a fork. If you have a pressure cooker you can do it in less time. Remove the potatoes from the water and mass mash them up real well. Add salt and pepper to taste. You can add other stuff for taste as well.
Corrected recipe: thanks Jacob.
Oops, I forgot to add the link to a less fun definition of mass.