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Posts Tagged ‘physical concepts’

It’s about time….

This post was written three days in the future from now. I have been informed that it is still not possible to send information to the past without messing it up. I hope this warning message makes it to you: do not travel to the past, I repeat, do not travel to the past. It’s messed up man….

As you can see, the laws of physics are still holding. The last of the three elementary concepts is time. Time seems to be different than space, and also than mass. Time is always there, never stopping, not once, not ever. Well, except in some seminars I attend to where time does seem to stop. I must check into that and see if I can profit.

So how do we notice that time is there? There seem to be these things that happen again and again and again and again. We call them days. Then we notice that there are these things called years: you notice because of the seasons, and if you happened to be a hunter-gatherer, the winters seem to have very little gathering available. Well, maybe a lot of wood-gathering to keep warm. But I digress. In some sense time is this little beast that lets us repeat stuff. However, there seems to be no rewind button, and let me tell you, there are times where I wish I had one…

 

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Well, that is what I imagine a friendly bet over beer in the middle ages would look like. Let us say two vikings taking a break after some invading of Europe. Not that things have changed that much. We still have silly bar bets over the sizes of *ahem*…

Graff and Olaff are in a desperate need for a meter stick.

Graff and Olaff are in desperate need of a meter stick.

So after some potato bliss, I had to think at great length about how to introduce some other elementary (in the sense of being fundamental, not easy) physics concepts. You see, it is hard to talk about physics without the three basic elementary irreducible concepts: mass, length, time.

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A market with no weight scales

A market with no weight scales

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.

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