10,579
edits
Changes
Activities/Sliderule (view source)
Revision as of 14:55, 13 September 2010
, 14:55, 13 September 2010→How to use a slide rule
== How to use a slide rule ==
== How to use a slide rule ==
There are three parts to the slide rule: (1) a fixed rule (either the D scale or the L scale); (2) a sliding rule (the A, C, or L scales); and a reticule, which moves independently of the rules.
There are three parts to the slide rule: (1) the '''stator''' (fixed rule); (2) the'''slide''' (a moving rule); and a '''reticule''', which moves independently of the rules.
To move the sliding rules, simply drag them. Also to move the reticule, drag it. ('''Note:''' The entire slide rule does not fit on the screen. By dragging on the fixed rule, you can scroll the canvas to reveal different sections.)
To move either the slide or reticle, drag it or use the arrow keys. You can also type into the labeled tabs to move to a specific value. ('''Note:''' The entire slide rule does not fit on the screen. By dragging on the stator, you can scroll the canvas to reveal different sections.)
Most calculations on a slide rule require three steps:
Most calculations on a slide rule require three steps:
# position the end of the top slide above a number on the bottom slide;
# position the end of the slide above a number on the stator;
# position the reticule over a number on the top slide;
# position the reticule over a number on slide;
# read the result from the bottom slide.
# read the result from the stator.
'''Note:''' You can read values from the fixed scale from either end of the sliding scale.
'''Note:''' You can read values from the fixed scale from either end of the sliding scale.
The Sliderule Activity displays these three values on tabs attached to the top slider and the reticule. The calculation is also displayed on the activity toolbar.
The Sliderule Activity displays these three values on tabs attached to the top slider and the reticule. The calculation is also displayed below the slide rule.
'''Note:''' The scales are all at a fixed scale. It is often necessary to move a decimal place in order to find the number you are looking for on the scale. It is up to the user to keep track and subsequently to estimate the decimal point in the final result.
'''Note:''' The scales are all at a fixed scale. It is often necessary to move a decimal place in order to find the number you are looking for on the scale. It is up to the user to keep track and subsequently to estimate the decimal point in the final result.
'''Note:''' You typically get 3 significant digits of accuracy when using a slide rule.
'''Note:''' You typically get three significant digits of accuracy when using a slide rule.
=== Multiplication ===
=== Multiplication ===
To multiply, you use the log slides, C and D. (Addition in log scale is the same as multiplication in linear space.) First position the end of the C slide over one of the multiplicands on the D slide. Then position the reticule over the other multiplicand on the C slide. Read the result off of the D slide.
To multiply, you use the C (log) slide and D (log) stator. (Addition in log scale is the same as multiplication in linear space.) First position the end of the C slide over one of the multiplicands on the D stator. Then position the reticule over the other multiplicand on the C slide. Read the result off of the D stator.
'''Example:''' 2 × 1.31 = 2.62
'''Example:''' 2 × 1.31 = 2.62
<gallery>
<gallery>
File:Sliderule-2D.png|Position the end of the C slide over 2 on the D slide
File:Sliderule-2D.png|Position the end of the C slide over 2 on the D stator
File:Sliderule-1.31C.png|Position the reticule over 1.31 on the C slide and read the results (2.62) from the D slide.
File:Sliderule-1.31C.png|Position the reticule over 1.31 on the C slide and read the results (2.62) from the D stator.
</gallery>
</gallery>
=== Division ===
=== Division ===
Division is the opposite of multiplication. First position the reticle over the dividend on the D slide. Then without moving the reticule, position the C slide so that the divisor is under the reticule. Read the quotient off of the D slide under the end of the C slide.
Division is the opposite of multiplication. First position the reticle over the dividend on the D stator. Then without moving the reticule, position the C slide so that the divisor is under the reticule. Read the quotient off of the D stator under the end of the C slide.
'''Example:''' 2.62 / 1.31 = 2
'''Example:''' 2.62 / 1.31 = 2
<gallery>
<gallery>
File:Sliderule-1.31C.png|Position the reticule over 2.62 on the D slide. Position 1.31 on the C slide under the reticule.
File:Sliderule-1.31C.png|Position the reticule over 2.62 on the D stator. Position 1.31 on the C slide under the reticule.
File:Sliderule-2D.png| Read the results from the D slide.
File:Sliderule-2D.png| Read the results from the D stator.
</gallery>
</gallery>
=== Overflow on Multiplication or Division ===
=== Overflow on Multiplication or Division ===
Sometimes the result of multiplication or division is off the end of the sliderule. For example 4 x 3 or 3/4. Here you can use the CI or inverse scale. To multiply you can divide by the inverse and to divide you can multiply by the inverse.
Sometimes the result of multiplication or division is off the end of the slide rule. For example 4 × 3 or 3/4. Here you can use the CI or inverse scale. To multiply you can divide by the inverse and to divide you can multiply by the inverse.
=== Square ===
=== Square ===
You use the A and D slides to square number. (A is a log-log scale.) Simply position the reticule of number you want to square on the D slide and read the result off of the A slide. (Remember to properly estimate the proper decimal point for your result.)
You use the A slide and D stator to square number. (A is a log-squared scale.) Simply position the reticule of number you want to square on the D stator and read the result off of the A slide. (Remember to properly estimate the proper decimal point for your result.)
''e''<sup>2</sup> = 7.4
''e''<sup>2</sup> = 7.4
<gallery>
<gallery>
File:Sliderule-e-squared.png|Position the reticule over ''e'' on the D slide and read the results off of the A slide.
File:Sliderule-e-squared.png|Position the reticule over ''e'' on the D stator and read the results off of the A slide.
</gallery>
</gallery>
=== Square root ===
=== Square root ===
You also use the A and D slides to find the square root of a number. Simply position the reticule of number you want to square on the A slide and read the result off of the D slide. (Remember to properly estimate the proper decimal point for your result.)
You also use the A slide and D statr to find the square root of a number. Simply position the reticule of number you want to square on the A slide and read the result off of the D stator. (Remember to properly estimate the proper decimal point for your result.) '''Note:''' the slide and stator must be aligned in order to calculate the square root.
√𝜋 = 1.77
√𝜋 = 1.77
<gallery>
<gallery>
File:Sliderule-root-pi.png|Position the reticule over 𝜋 on the A slide and read the results (1.77) off of the D slide.
File:Sliderule-root-pi.png|Position the reticule over 𝜋 on the A slide and read the results (1.77) off of the D stator.
</gallery>
</gallery>
=== Subtraction ===
=== Subtraction ===
To subtract, you also use the linear slides, L and L. Position the reticule over the minuend on the lower L slide. Without moving the reticle, position the upper L slide so that the subtrahend is also under the reticle. Read the difference from the lower L slide.
To subtract, you also use the L (linear) slide and stator. Position the reticule over the minuend on the L stator. Without moving the reticle, position the L slide so that the subtrahend is also under the reticle. Read the difference from the L stator.
'''Example:''' 3.2 – 2.1 = 1.1
'''Example:''' 3.2 – 2.1 = 1.1
<gallery>
<gallery>
File:Sliderule-LL2.png|Position the reticule over the minuend (3.2) on the lower L slide and the subtrahend (2.1) on the upper L slide.
File:Sliderule-LL2.png|Position the reticule over the minuend (3.2) on the L stator and the subtrahend (2.1) on the L slide.
File:Sliderule-LL1.png|Read the difference (1.1) from the lower L slide.
File:Sliderule-LL1.png|Read the difference (1.1) from the L stator.
</gallery>
</gallery>