Topic One: DATA & WORD
Computers are just things made of glass, metal and plasic. They do not understand anything. They do not think. The only thing computers really understand about hte world around them is where electricity is moving through their circuits.
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A circuit is allows electricity to flow to do work, like turn on a light or turn a wheel. What the video below on what a circuit is.
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We needed to create a language that both computers and humans understand. Since computers can only have circuits that are on and off, we decided base this language on whether circuits are on or off. If a circuit is ON = 1, otherwise, if the circuit is OFF = 0.
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Sounds like a difficult language to learn if you only have two symbols 1 and 0, so we developed the number system called BINARY.
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Let's go back to something we are more familiar with: Decimal! Decimal is a number system based on the number 10 and it uses 10 symbols (0,1,2,3,4,5,6,7,8, and 9) to make all the numbers. In the Table below you can see how deecimal numbers are made up of powers of 10. The three is in the thousands place, the 2 is in the hundreds place, 4 is in the tens place and 8 is in the units place.
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Binary works the same way only with only TWO symbols (0 and 1). Instead on being in powers of ten, each place is a power of 2. So now we have a units place, a 2s place, a 4s place, an 8s place, a 16s place etc. You will recognise these numbers because they are used to measure the memory capacities of smart phones, USB memory sticks and computer hard drives and RAM.
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NUMBERS
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Each Binary number can only use zeros and ones in each of the places. If you look at the table below, you can see that the values of 0 to 5 are listed as binary numbers. Zero and one are easy - they are the same as decimal. But for 2 we put a one in the 2s place and a zero in the units place. For 3, we put a one in the 2s place and a one in the units place because 2 + 1 = 3. We have used up all the symbols now so we have to use a new place, the 4s place, so 4 is 100. 5 is one in the 4s place and a one in the units place with a zero in the 2s place.
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See if you can count to 20 in binary!
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TEXT
So now we know how to count numbers in Binary, but how do we use words?
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Each 1 and 0 is called a BIT.
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8BITS = 1 BYTE.
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Every letter, number and symbol you can type on your keyboard is represented by a byte. For example the capital letter A is: 01000001.
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CLASS ACTIVITY
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The teacher will send the class a secret message using a light. when the light is ON, it will represent a 1. when the light is OFF, it will represent a 0. The teacher will count to 8 and students will write the eight 1s and 0s down that represent each letter.
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The the students will go to THIS WEBSITE to convert the byte into a letter.
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DATA TYPES
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There are five main data types: Text, Numbers, Images, Sound and Video. We have just covered how numbers are created by binary.Text is made up of letters, numbers and symbols. Above, we explored how each letter and symbol is represented by a byte (made of eight bits).
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IMAGES
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Digital images are displayed as pixels on a screen. Have a look at this video where an artist displayed video footage as binary pixels.
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Images are made up of pixels or objects, but predominantly they are different from text and number by the use of colour and tone. Colour uses a different number system called Hexadecimal - a system based on the number 16. Don't Panic! You don't need to know how to count in hexadecimal, but you do need to know a couple of things.
To have a number system that hold 16 different symbols we add letters to the numbers we already have:
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0,1,2,3,4,5,6,7,8,9,A,B,C,D,E and F.
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A = 10
B = 11
C = 12
D = 13
E = 14
F = 15
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So now we can make numbers using combinations of all this symbols. Example #F5E227. We use a hashtag (#) in front of a hexadecimal number to make sure people know it is a hexadecimal number.
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You may be familar with primary colours in art: yellow, red and blue combining to make all the other colours. This happens when you use paint or ink, but when using computers we are using light. The mixture of colours works differently with light. Light has differnt primary colours: Red, Green and Blue. We always list them in that order too.
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We group our Hexadecimal colours in the same way; the first two values are red, the second two are green and the last two are blue:
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RED GREEN BLUE
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# 0 0 0 0 0 0 Here we have zeros for each colour. If you turn DOWN the lights to zero - you get BLACK!
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# F F F F F F Here we have Fs for each colour. If you turn UP the lights to F (the largest number - you get WHITE!
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# F F 0 0 0 0 Here we have Fs for only the two places for RED and all the others are zero - this makes RED!
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# 0 0 F F 0 0 Here we have Fs for only the two places for GREEN and all the others are zero - this makes GREEN!
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# 0 0 0 0 F F Here we have Fs for only the two places for BLUE and all the others are zero - this makes BLUE!
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# F F F F 0 0 Here we have Fs for bothe RED and GREEN this makes YELLOW!
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CLASS ACTIVITY
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Open Photoshop and double click the colour picker. Here we can select colours and see the hexadecimal numbers for each colour. What happens when you put the following in?
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#222222
#DDDDDD
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Why is one lighter than the other?
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SOUND
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Sound is created by sound waves of compressed air hitting our ear drums. To turn those waves into sound recorded onto a computer, the computer needs to sample the sound and convert those samples into numbers (so it can understand it in binary). Our ears are very sensitive need a lot of samples - in fact: 44,100 samples per second to make the individual samples connect up to sound like continuous sound.
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Watch the video above to see how each of those samples create a continuous sound wave.
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VIDEO
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Video is made up of sound waves in one track and a stream of still photographic images in another track. Our ears may be very sensitive, but our eyes are not so. We only need 24 frames per second to see continuous movements between each frame.
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CLASS ACTIVITY
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Students should learn how to create, save and edit WORD files.
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Skills to learn:
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Font Type
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Font Size
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Font Colour
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Add dot points
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Alignment
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Orientation to landscape
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Size to A3
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Create 2 – 3 Columns
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Text boxes
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Shapes
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Lines
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Header to include the students name and class.
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Shape Fill
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Shape Outline
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Shape Effects
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Wrap Text
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Page Colour
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Page Border
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Word Document “Student Name_Poster.docx”
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PDF “Student Name_Poster.PDF”
FILE TYPES & SIZES
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Different data types define what FILE type will be created. If you are writing an essay - you will not choose PowerPoint to do it in. You would choose Word because it allows you to edit your text easily. Then when you save your word file you have a range of different text file types to choose from. The most common are word docx and pdf. Some file types are compress the data into smaller sizes than others so they can be emailed or uploaded. Most files sizes are in Kilobyes or Megabytes. See the diagram below.
High and Low Quality
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Sometimes you want files to be large so you do not lose any quality. A photograph that you want to print out may have lots of pixels per inch giving it a high resolution and large file size. It might not be able to be emailed or uploaded easily, but it will be perfect for including in a printed document.
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On the flip-side, sometimes you can sacrifice a little quality to make the file smaller so it can be easily shared online or emailed. A common example is a jpeg or gif imag. These are compressed files that lose the number of pixels so it can make the file size smaller. Another common example is sound. When you try to replicate sound waves it takes a lot of data. To compress that data into a smaller size, the MP3 file type allows for a little loss of quality for a compact size. Now we can fit hundreds of songs on our smart phones.
CLASS ACTIVITY
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Students create a POSTER is Word to illustrate everything you have learned about data types, file types and sizes. See the illustration example below as a model for you poster. You do NOT need to recreate the poster exactly - try to put together your own version with your own creative flair.
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