tag:blogger.com,1999:blog-3177836936631247789.post5955817015744591158..comments2024-11-10T04:13:33.369-08:00Comments on Retro Educational Technology: The Slide RuleUnknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-3177836936631247789.post-517573212801923822013-01-02T13:14:19.259-08:002013-01-02T13:14:19.259-08:00Slide rules are as simple or as complicated as the...Slide rules are as simple or as complicated as the user. The most basic thing they do is multiply or divide. Notice on your slide rule there are several "scales" labeled A, B, C, D. The C and D scales are the "fundamental" scales that are used for almost everything. They are identical and can slide against each other (hence, slide rule). The numbers on the slide rule are spaced out *logarithmically* - don't worry about the exact meaning of this, just understand that the numbers increase "faster" as you go from left to right. In fact, they do so at a rate that means that a linear distance (e.g. one inch) from one point on the scale to another point (say, to the right) is *always the same amount of multiplication*. HUH? In other words, the distance from "1" to "2" on the C scale (i.e., "times two") is the same as the distance from "3" to "6" on the C scale (also "times two"). Wow! What can you do with this? Well, if you want to multiply 33.2 x 176, you can do it like this:<br />1) move the scale so that 1 on the C scale is directly over 3.32 on the D scale. This means that now everything on the D scale is equal to 3.32 times what is on the C scale!<br />2) now just look at 1.76 on the C scale. The corresponding number on the D scale will be 3.32 times 1.76, which in this case is shown as... um... 5.84.<br />3) okay, obviously, we've got one last step. We wanted 33.2 x 176, and we have 5.84. This is a limitation of the scale, we have to account for magnitude. 30 x 200 would be 6000, so we have a good idea that our answer should be in the thousands. So we turn our answer into 5840. Not quite the calculator answer of 5843.2, but "good enough," right?<br /><br />That's just one kind of operation you can perform on a slide rule. Depending on which scales are on your slide rule, you can also perform exponents (the A and B scales), trigonometry (the S and T scales), logs of logs (LL scales), unit conversions, atomic mass references, almost anything...<br /><br />Really all you have to understand is that a slide rule is a way to refer two scales against each other in a useful way.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-3177836936631247789.post-17069271899288441812012-10-23T23:06:33.540-07:002012-10-23T23:06:33.540-07:00slide rules are easy...
to multiply you add.
to d...slide rules are easy...<br /><br />to multiply you add.<br />to divide you subtract.<br /><br />the scales are logarithmic which is the magic that makes it all work. bulwynklhttps://www.blogger.com/profile/10185562033727791670noreply@blogger.com