1. How do the parts of a computer communicate?
Have you ever wondered how your key board communicates with the computer, and how the computer communicates with the screen?
Here we are providing a real world context.
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2. They communicate in numbers . . .
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3. They can make a whole language by using place value!
. . . but they only use
two numbers,
0 and 1.
Computers communicate with 2 numbers, and have a whole rich language by using place value with those two numbers.
They can make a whole language by using place value!

4. We have 10 fingers Base 10
Place Value tells what the number in the place value column is multiplied by.
137 = 1 hundred 3 tens 7 ones
Here is another example, just to help us be more aware of what we take for granted, since we are so used to our place value system.
We only have 10 digits, but we can write unlimited number of numbers because we have place value.
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5. Computers don’t have 10 fingers! They have 2!
Only 2 values
0, 1
Off and On
Place Value, same as Base 10
Read number Left to Right
Zero place-holder
Ones, twos, fours, eights, sixteens, thirty-twos
Compare this information to what we know about Base 10. There are 2 digits, 0 and 1. We need that zero for a place holder.
The place value system works the same way. The numbers read form left to right. Zero is the place-holder.
But the values of the places are different. How do we make sense out of those places?
We are going to look for a pattern. Tell them this is another problem solving skill, looking for patterns.
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6. Compare Base 10 and Base 2 Place Values Base 10 Base 2 1 = 1 10 = 10
10 x 10 = 100
10 x 10 x 10 = 1,000
10 x 10 x 10 x 10 = 10,000
Base 2
1 = 1
2 = 2
2 x 2 = 4
2 x 2 x 2 = 8
2 x 2 x 2 x 2 = 16
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7. Base 2 Place Values 1 = 1 See the Pattern? 2 = 2 2 x 2 = 4
1 = 1
2 = 2
2 x 2 = 4
2 x 2 x 2 = 8
2 x 2 x 2 x 2 = 16
2 x 2 x 2 x 2 x 2 = 32
2 x 2 x 2 x 2 x 2 x 2 = 64
Some students will take longer to be able to predict what comes next. Or even if they made the pattern, they’ll feel good about having their understanding reinforced.
See
the Pattern?
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8. Writing Numbers in Base 2
Subscripts tell what "Base" a number is
30710 means 3 hundreds and 7 ones in Base 10.
Subscript
The small "10" written a little bit lower and to the right of the number is a Subscript
If students learn how to use subscripts, this will be one less thing to learn later. This is part of the language of mathematics.
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9. Example 1 Base 2 1012 = 1 four, 0 twos, and 1 one
Place Value tells what the number in the place value column is multiplied by.
1012 = 1 four, 0 twos, and 1 one
10112 = 1 eight 0 fours 1 twos 1 one = 1110
101 in base 2 has a 1 in the 4’s place and a 1 in the one’s place. If we want to know what that is in base 10, it is one 4 and one 1, so it is 5. Notice we use the subscript. We are using two different bases so we have to use the subscripts.
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10. © 2009 EDSTAR, Inc.
Binary Codes
Your computer, CDs, key board, and monitor use things that have only two states.
0 and 1 can be used to represent those two states. Because of that, they can talk to each other in Base 2.
They have to speak the same language or they wouldn’t understand each other. But they are all very different. They use different things to stand for 0 and 1, but they can all speak in base 2 and understand each other.

11. ASCII is a code for writing letters in Base 2.
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ASCII Code
ASCII is a code for writing letters in Base 2.
The keyboard sends an ASCII code message to the computer telling what letter was just typed.
Computer makers all agreed to use the same code to stand for things. This is called ASCII Code. The keyboard uses ASCII code to send a message to the computer. The letter A is coded 65, but the keyboard can only talk in base 2, so it has to send a 65 in base 2. That would be electrical connections of “off, on, off, off, off, etc….”

12. Here is part of the ASCII code
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ASCII Code
Here is part of the ASCII code
Computer makers all agreed to use the same code to stand for things. This is called ASCII Code. The keyboard uses ASCII code to send a message to the computer. The letter A is coded 65, but the keyboard can only talk in base 2, so it has to send a 65 in base 2. That would be electrical connections of “off, on, off, off, off, etc….”

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Bitmaps
A display screen on your monitor is a bunch of boxes. These boxes are called “pixels.”

14. Bitmaps Resolution Display on a screen or print…
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Bitmaps
Display on a screen or print…
Resolution
Let’s see how a binary code is used to make the display.
More pixels make a smoother shape.

15. Write out the 0’s and 1’s in a Code.
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Bitmap Codes
Write out the 0’s and 1’s in a Code.
The screen reads the message and uses a bit map code to turn on or off pixels.

16. Here is part of the Bitmap code
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Bitmap Codes
Here is part of the Bitmap code
This is how the computer sends the code to the screen so it can display a letter.

17. Disk drives use magnetic signals to communicate.
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Magnets
Disk drives use magnetic signals to communicate.
Disk drives speak with magnets. They use magnets to read other magnets.