Science Tutor Tips: Dimensional Analysis

One of the most intimidating aspects of physics is the math involved. A science tutor can help you work through the math part of your physics questions, but there should be an easier way. That's what this weeks science tutor video is all about. The "easy way" is through dimensional analysis.

Dimensional analysis is a common science learning "short cut" that will help you to learn science faster. It's a tool for keeping all of the units of measure straight and in the right place. This is more important than you might think.

For example, when you work on a Newtonian physics problem, you might be dealing with force, acceleration, work, power, etc. All of these values are derived from other values of time, distance, and mass. You might have to convert one unit to another. Your problem might involve meters, Joules, kilograms, watts, ergs, or years. You could express your answer in one or more of these values. You might have to convert one unit to another one.

In this video, I've presented a shortcut to dimensional analysis. You create a long horizontal line, and then divide it into columns for each unit of measure that your science problem requires. There's an immediate, invaluable benefit to this method. Since you can cancel out the units of measure that appear on both the top and bottom, you can test your answer before you get bogged down in a lot of calculations.

For example, suppose your physics question involves force, displacement, mass, and work. You lay it out, and cancel out the units of measure. Soon you're left with a lot of numbers,, with meters on the top and seonds on the bottom. This indicates that your answer will come out in meters per second. If you were calculating speed or velocity, you know that you've probably set up the problem correctly. If you were supposed to calculate the work done by a system, then obviously something is wrong.

You'll notice in the video that I made a mistake in setting up my problem. I could have edited this part out, but I left it in to show you how this system allows you to self-correct before you finish the problem. This can be a huge time saver!

I'm sorry that this week's science tutor video is so long and boring. But please watch it, because this technique is very useful and valuable, especially for science problems in chemistry and physics. It's worth eight minutes of minor discomfort, if you ask me.

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