SLIDE RULE FOR GRADE LEVEL:   

                ,              , 5th to 6th 

enter number for C1 to be over  ( ? )  

C1 now over  ( ? )  

enter number for C to be over on D  ( ? )  


























  Important   main cursor  instructions!      HIDE,  SHOW, WHY



 nudge the slide:  read all about this


 read all about this
   
selected cursor over:      x = D = A    B =    C    CI note:   D  value is often referred to as x
arcsin(.1x):   arccos(.1x):   arctan(.1x):   x^2: x^3:   R1(x):   R2(x):   L(x):  
    choose)  cursor over:   LL3   LL2   LL1   LL0   LL3   LL2   LL1   LL0  
C1 over:        D   LL3   LL2   LL1   LL0   LL3   LL2   LL1   LL0  


  find out more about this calculus example HERE. ( ? )
Things don't work or look right? - created 5/10/08 so may not work with all modern browsers
- modified 5-2-22 to work with some newer browsers - PCs only -
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main cursor and auxillary cursor references

under construction

Click on any of the numbers, and a cursor (pointing device) will appear on the slide rule. There are three of them. These are considered to be auxillary cursors, and can be used as such, as discussed below

The arrow below the red lines can be touched with the mouse and slid left and right.

When complete, it will serve as a cursor mark index. There will be display boxes here for trig functions (sin, cos, etc) as well as most of the other numeric data found on normal slide rules. The boxes will display the numeric value located below the selected index marks.

The other 3 marks are cursors for your use. Simply click the number below one of the cursors and it will jump up to the slide rule. Once the cursor is on the slide rule, any movement will display the relative values within the boxes to the right. Simply click the number again to return the cursor to the "docking station". The "main cursor line" sliding arrow will also be reimplemented for the auxillary cursors - in other words, it will slide all the way to the right so the data below an auxillary cursor will be displayed within the output boxes.

All cursors will be connected the "nudge" function as well as the future proposed "click to" function.

For now, there aren't any output boxes, so none of this means very much... but go ahead and play around with the marks if you want.
































































































 
Recent errors

This is all new stuff for me, so there are bound to be some errors - usually referred to as "bugs". Below is a list of some, found and fixed:

1.) When the slide of the slide rule was slid to the right or left, it would never stop - as long as you kept sliding, it would slide way past the slide rule and continue until you let go of it. (fixed)

2.) When the screen was resized, everything on the screen would get all bunched up. (fixed)

3.) If the first digit of the first number entered for the group of C over D entry boxes, was bigger than first digit of the second number, the slide would move to an incorrect location. (fixed)

4.) An error in the javascript (one of the programming languages) that I use for my code to make this webpage, created a rounding error in some number relationships. For example if 3 was entered in the first box of the two box grouping of C and D, and 15 was entered in the second, the value in the "C1 now over" box would be something like 5.0049, rather than 5, as it should be because that sequence of events divides 15 by 3 which should produce an answer of 5. (fixed)

6.) An error involving not being able to set the slide to a precise whole number by sliding it. It was only possible to do so by using the input boxes. (fixed)

7.) Value in box marked "C1 now over" was set to 0 on load instead of "1.0000". (fixed)

8.) Link to hide or show cursor was also causing slide position to reset to 1, which isn't necessarily desirable. (fixed)

9.) The font color was messed up in some browsers. For example, most of the fonts are black, but in some it would show as light green or something else really strange. (fixed)

more errors yet to be discovered . . . .
































































































 
Future plans

This automated slide rule is a "work in progress". One of the future goals, is to allow values which are sent to this page from other pages to set the slide rule to an applicable position. For example, if explaining, on any web page elsewhwere, "set slide rule to C1 over D32, a link may be provided to this page, whereupon arrival, the slide on this virtual rule
will be set to that particular position.

There are many more future plans for this slide rule. I plan on adding all kinds of numerical relationships between the values on the "Kid's Rule!" slide rule and the most advanced slide rules - some for the older kids, and some just to help make it fun for the parents and teachers as they learn along with their kids. One example is trigonometric relationships. For example, you simply move the slide and you will see the sine, cosine, and tangent values that would create the corresponding output. Or enter a value and have the slide move automatically showing the trigonometric relationship. Another example is logarithmic outputs and inputs.

I'll use some of the most modern programming techniques, so some of the features may not work with all browsers. I'll be programming for Microsoft's Internet Explorer, but many of the browsers are making an attempt to support modern coding techniques.
































































































 
What do the numbers mean?

enter number for C1 to be over:
C1 is considered an "index". There are two of them on the C scale. The C scale is on the bottom part of the set of scales that slide and is marked on the left side with the letter "c". This scale is usually placed over the multiplicand in a multiplication problem. So, in the number beside this text, you might want to enter a number such as 3 if you want to multiply 2x3. If you do, then the answer will be found on the scale marked at the end with a "d" (referred to as the D scale) below the 3 on the C scale.

enter number for C  [ ] over D [ ]
This is often a function used for division, in which a divisor on the C scale is placed over a dividend on the D. The answer will be found below C1 on the D scale. You can also see that answer in the second box marked, "C1 now over".

Finally - what do the numbers mean?
The interesting thing about the slide rule, is that any one number can mean lots of different things, by just adding zeros, or moving a decimal point around. For example, if you enterd 2, 2000, or .02 in the first box and pressed the button, the C1 index would move the exact same spot each time. Rather than carrying around a slide rule for 1's, 10's, 100's, 1000's, and more, you just allow the number to be whatever "fits" the problem you are doing. So, if you want to multiply 2x3, you put C1 over 2, and look for the answer below C3 on the D scale. you would do the exact same thing for 20x30, or 2x300. The answers to those problems are, 6, 600, and again 600.

You can enter whatever you want in the boxes, and the slide rule will move to the correct location.

more to come . . . .
































































































 
Why Hide Cursor?

The cursor is used to help our eyes see which marks are lined up with each other. For example, if a number on the CI scale, is placed over a number on the D scale, it can be difficult to align it perfectly. Also, if one of the small lines between D2 and D3 is used in a division problem as the dividend, with the divisor of, for example, a number between C3 and C4, then it becomes easier to keep track of the marks if we first place one of the cursor lines over the number between D2 and D3 and then slide the slide so that the number between C3 and C4 is below the same cursor line. The answer to that problem can then be found below C1.

The cursor is not always needed if the alignment of the marks is very simple to see. For example if C1 is placed over a multiplicand, with a multiplier such as C3, with the answer of D6, then all of those numbers are very easy to see and the cursor might even be considered to be "in the way". For that reason, I've given the option to hide the cursor. On the virtual "Kid's Rule" it's easy to hide the cursor - on the real "Kid's Rule!" slide rule rule, you would need to know some magic to hide the cursor.
































































































 
THANKS TO -









































































 
The Making -

Perhaps the toughest thing in making the virtual rules here was the "trial and error" process of scaling the images and the artwork required to create the transparent cursor. The scaling required a lot of tries in order to achieve the best representation of the actual slide rule, on the PC video monitor. The cursor is comprised of multiple layers of images, combined to create the look of glass. The "Kid's Rule!" slide rules that have extra scales that aren't connected between the main slide, have a sliding cursor. The cursor of the Virtual Rule is intended to represent that cursor.

The main body and slide of the rule is comprised of a couple of images (processed as described above), resized, and manipulated, using the ideas of Derek Ross, and of course the special code of Walter Zorn that makes the sliding possible.

Although this scaled down virtual version of the "Kid's Rule!" is accurate enough for most of the lessons presented within this site, it is not nearly as accurate as the "Real Thing". Due to PC video monitor pixellation the "Kid's Rule!" would require a monitor near 3' wide to accurately display the lines as they actually are.
































































































 
The WinApp -

That's right! A virtual slide rule for Windows 98/2k/XP/Vista

Some may have played around with the virtual Kid's Rule! slide rules  elsewhere  at this website - now you can get something even better to run on your PC. The windows application, unlike the browser based one, allows you to enter values for any of the boxes. It even contains a handy note-keeper pad so you can keep notes of your progress working with the slide rule, or just jot down notes, or cut and paste from other resources.

There is a free   demo application  available now.

Note the required 1280 wide screen resolution. The demo app is a good way to try everything with your system before considering the $8.00 purchase of the full application which will be available soon.

A special thanks to  TheSlideRuler.Org  for involvement in this project!








































































note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

under construction

When an auxillary cursor is placed on the slide rule and the mouse is passed over or clicked on it, the corresponding numerical results will be displayed within the boxes

The cursor related data is currently displayed only when a cursor is moved.









































































note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

under construction

I'll be adding more output boxes for all scales (A/B/C) as well as individual output for each cursor. Output boxes will include things such as LL0, LL1, LL2, K, R1, R2, and more.

There will also be some more cursors added to be used for indexing the various scales which do not appear on the slide rule, but can be referenced in relation to D (often referred to as X. In addition to the cursors, there will be additional output boxes for reference to each cursor. My intention is to make the abundant display of output boxes "displayable on demand" so as to not clutter the screen when not being used.

A lot of this is obviously not for the kids, but is intended for a fun interraction between parents and kids.









































































note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

Click on any of the numbers, and a cursor (pointing device) will appear on the slide rule. There are three of them. These are considered to be auxillary cursors, and can be used as such, as discussed below

The arrow below the red lines can be touched with the mouse and slid left and right.

When pointed to a red line within the small image of the cursor, the numeric values associated with that mark on the full-size cursor will display within the boxes. Likewise, when it's placed below one of the auxillary cursor marks, if that cursor is up on the screen (not "in docking") the numeric values associated with that cursor will display within the output boxes.

This provides easy access to values below any cursor without moving a cursor. Of course, any cursor when moved, automatically displays the numeric values associated with the cursor. All cursors will be connected the "nudge" function as well as the future proposed "click to" function. And... further down the road, you will be able to reference the cursors in mathematical functions. In other words, you enter the equation with a reference to a cursor - Aux1 for example - and the value associated with that cursor will be "plugged into" the formula.

For now, there are only a few output boxes, but there will be more!

note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

Whichever line the mouse cursor is nearest within the main sliding cursor, is the line that will determine the numeric data displayed in the output boxes.

Click the HIDE link to hide the cursor and SHOW link to make it visible if it is hidden.

Pass mouse over the WHY link to explain the hiding and showing of cursor.
note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

Use the values below to "nudge" the slide left or right. Be sure to watch the "C1 now over" box at the top of the page, since the movement will be relative to the current position reported within that box, which may not always be what you think it is. Also note, that because of screen resolution, slide movement in small increments may not be visible, but will still be correctly reported within the box mentioned above.

Thanks to Ray from the sliderule group for the idea!

note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

This was just put here for fun. Using calculus with x^2, as is being done here, is one of the simplest things to do in calculus. Calculus can be very difficult, but can also be very fun - just like all math!

Now, go tell your friends that you've done a little calculus... on the "Kid's Rule!" virtual slide rule.

Later, I'll be back to show you step-by-step how to do this on the slide rule and also explain exactly what it all means in a way I think you'll understand.

To learn more about calculus, see the wikipedia explanation here.

note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

C1 is considered an "index". There are two of them on the C scale. The C scale is on the bottom part of the set of scales that slide and is marked on the left side with the letter "c". This scale is usually placed over the multiplicand in a multiplication problem. So, in the number beside this text, you might want to enter a number such as 3 if you want to multiply 2x3. If you do, then the answer will be found on the scale marked at the end with a "d" (referred to as the D scale) below the 3 on the C scale.

note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

Enter a C scale number in the top box, and a D scale number in the lower box. Use the  PRESS  button to move the slide, placing the C scale number over the D scale number.

This is often a function used for division, in which a divisor on the C scale is placed over a dividend on the D. The answer will be found below C1 on the D scale. You can also see that answer in the second box marked, "C1 now over".

note: click the left mouse button anywhere on the screen to close this box, and then wait for it to fade away completely before again moving the mouse.

The number in this box, if for example a 5, can also mean 50, 500, 5000, etc., or even .05, .005, .0005 - it all depends on the relevance to the mathematical problem of the alignment of a number on the C scale over a number on the D scale.

The interesting thing about the slide rule, is that any one number can mean lots of different things, by just adding zeros, or moving a decimal point around. For example, if you enterd 2, 2000, or .02 in the first box and pressed the button, the C1 index would move the exact same spot each time. Rather than carrying around a slide rule for 1's, 10's, 100's, 1000's, and more, you just allow the number to be whatever "fits" the problem you are doing. So, if you want to multiply 2x3, you put C1 over 2, and look for the answer below C3 on the D scale. you would do the exact same thing for 20x30, or 2x300. The answers to those problems are, 6, 600, and again 600.

A good example of all this is the values that appear in the "C1 now over" box if you press the button beside the "enter number for C . . . over D" entry boxes, using the default for those boxes of, C=212.56 and D=5.78934. That is the same as if you did the division problem on a handheld calculator: 5.78934/212.56 which would give you the answer of "0.027236". The answer to that problem here shows 2.7236, because the slide rule has no way of knowing if you meant, "5.78934", "500.78934" or any other number. Even though the entry boxes know exactly what you entered, the slide rule is performing the division by placement of the slide and the result being presentend in the "C1 now over" box is the answer that I then format with a single digit left of the decimal point, regardless of the answer. If you give it some thought, it's pretty simple to figure out - if you divide those two numbers, the final answer to use will have the decimal point such that the result is "0.027236" - one clue, being that there is a two-decimal point difference between the dividend rounded to "5" and divisor rounded to "212". Due to so much use of the handheld calculators, I've discovered that many parents have even forgotten such simple mathematics.

A strong advantage of the slide rule, in regard to the learning of math, is that it requires that a little more thought be given to the problem at hand, than might be the case with a similar problem on a hand calculator. This process, helps to make the slide rule a great learning tool for kids.

The cursor is used to help our eyes see which marks are lined up with each other. For example, if a number on the CI scale, is placed over a number on the D scale, it can be difficult to align it perfectly. Also, if one of the small lines between D2 and D3 is used in a division problem as the dividend, with the divisor of, for example, a number between C3 and C4, then it becomes easier to keep track of the marks if we first place one of the cursor lines over the number between D2 and D3 and then slide the slide so that the number between C3 and C4 is below the same cursor line. The answer to that problem can then be found below C1.

The cursor is not always needed if the alignment of the marks is very simple to see. For example if C1 is placed over a multiplicand, with a multiplier such as C3, with the answer of D6, then all of those numbers are very easy to see and the cursor might even be considered to be "in the way". For that reason, I've given the option to hide the cursor. On the virtual "Kid's Rule" it's easy to hide the cursor - on the real "Kid's Rule!" slide rule rule, you would need to know some magic to hide the cursor.

































































































- copyright 2008 Tim Van Dusen -
















































dTrack:   cTrack: