Topic A : How computers work (6 lessons)

Task 2.2 Classify these!
Where we learn to classify hardware devices

Do as it says!

Download and complete the worksheet

Download the worksheet Classifying hardware and save it in a suitable place in your documents. Complete the worksheet after the class discussion by identifying ...
  • What each device is called;
  • Whether it is an input, output, processing, storage or ancillary device;
  • What it is / could be used for.
Print out your work for assessment

When the allocated time for the task is over, print out the document for assessment - remember to put your name and your class in the header section. You may self or peer assess this. Make sure that you give your sheet back to your teacher or they will not be able to check how you have done.
Any old iron!
How does it work?

Just a little bit of fun with my favourite microprocessor, the Intel 4004. Below is a Sketchup Model that you can interact with and there is a picture of the 'mask' (layout) of the 2300 components from the topic presentation.

3D Sketchup Model of Intel 4004. Click to enable 3D viewing.

The Intel 4004

The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. It was the first commercially available microprocessor by Intel and the first in a long line of Intel CPUs. The chip design started in April 1970, when Federico Faggin joined Intel, and was completed under his leadership in January 1971. The first commercial sale of the fully operational 4004 occurred in March 1971 to Busicom Corp. of Japan for which it was originally designed and built as a custom chip.

Task 2.3 Storage is getting cheaper!
Where we about relative storage quantities and the fact that it's quite impossible to visualise them

Re-watch the video

Firstly, re-watch the 'Powers of 10' video that you saw in class. Remember that some of the units of measurement are different now so you might not recognise some of them - ask your teacher and see if he or she does.

Re-watch "Powers of 10" (9:01)

Explore the universe!

Next, spend a few minutes (that's all) exploring the universe in all it's minute detail. Click on the objects to learn more about them but don't forget the scale of things!
Click to visit the interactive animation

Design a mnemonic

In order to help you to remember the order of data storage units, design a mnemonic where the first letter of each word in your sentence is the same as the first letter of the data storage unit. Chat with your shoulder partner but don't write anything down yet ...

Download and complete the worksheet

Finally, download the worksheet Data storage and complete the activities contained therein.
Data quantities
Data storage timeline

What is 'software' and why do I need it?

Software helps our computers to do useful things. Even embedded systems like traffic lights, washing machines and DVD players need software to run though this may be written in very different languages than the software that we use on desktop computers.

Task 3.1 On the air!
Where you create a script for a radio show about software applications

Download and complete your script (you might want to do this in pairs)

You task is to write a script for a radio program called TechReport. First, you will need to download the partially completed script, On The Air, and save it to a suitable place in your documents. Open the document, complete the header and footer and replace the red writing with your part of the script. Use the slides ...
... to help you.

Try to make use of the following shortcut key combinations to save you time ...


(If you struggled to complete this task, you can download a copy of my solution to help you with the next bit - shhh!)

Record your interview!

Now get your headphones on and record your interview using software like Audacity. You might want to work in pairs with one microphone or record each part separately and combine them together.

You can download some jingles for the start and the end from the following websites ...
Great jingles - nice and short!
Full tracks which need cropping
Hardware to software
No more Windows!

Task 3.2 File extensions
Where we about relative storage quantities and the fact that it's quite impossible to visualise them

Complete and print the online worksheet

It's important that you know some common file extensions, if only for common Office applications. Click on the image below, complete the online worksheet, fill in your name and click the print button to print for assessment. 
Click to open worksheet

How do computers store data?

It's not one of the tasks, but read this ...

Computers are made of billions of tiny electronic switches called transistors which can be switched on or off. This is great, because it means that a computer either does or it doesn't signal that some event has happened. These on / off signals can be used to indicate a value, a character (like a letter, a numeral or a symbol), a coloured pixel in an image or a tiny portion of a sound wave - it depends what we decide an 'on' or an 'off' means.

Therefore, everything that computer systems stores can only be stored using a sequence of on's and off's.

Using patterns of course!

Task 4.1 Patterns
Where we learn how patterns can be used to represent different things

Get your headphones on and watch this video

This truly is a 'crash course' in computer science - I've never heard someone go through the whole of the binary number system, number encoding, binary maths, character encoding, images, colour and sound in just over 10 minutes. Hold onto your hats ...

Representing Numbers and Letters with Binary: Crash Course Computer Science #4 (10:45)

That's a really good idea!

Watch the video again and make some notes

Now watch the video again, but this time, try to make some notes. You can pause the video by pressing the  SPACEBAR  and skip forward and backward using the  LEFT (←)  and  RIGHT (→)  arrow keys. Don't try to write everything down - this is practice for you to see if you can spot the most important aspects of the video. Try using ...
  • Pictures
  • Spider diagrams
  • Short sentences
  • Key terms
... to make your notes. Your teacher might need to model with with you first.

Task 4.2 Binary numbers and simple maths
Where we learn how to represent denary numbers using binary and how to 'do' binary maths

Rewatch the video!

If you want, get your headphones on and re-watch the video you saw in the lesson. In the video, Mr Mills teachers us all about binary numbers, switches, binary mathematics and adder circuits. Sometimes he gets confused and sometimes he's as clear as a spring dawn.

Binary Numbers (31:07). It's a long one but you can pause it!
In the video, we learn ...

» That computers are made out of switches;
» How to count in different number bases;
» Rules of addition;
» How to add numbers using electronic circuits.

If you want to practice using the ACMETM 5-Bit Full Adder, click on the image below and print yourself off a copy!
Click me and print yourself off a copy!

(Download and) complete the worksheet

If your teacher hasn't already given you a copy of the worksheet, Binary Shopping, you might need to download it and print it yourself. Don't worry about grabbing the one you printed as long as everyone who prints one takes one.

Complete the first side of the sheet!

Try to work out how much each of the items in my Binary Shop costs. *Don't* move onto the second side of the sheet until you have assessed your answers.

Now, complete the second side of the sheet!

Again, if you want to watch the video to remind yourself how to add binary numbers together, now is a good time to do it. When you are ready, have a go at the questions on the second side of the sheet (you can assess your answers using the presentation but make sure that you have shown your working including any carry bits).
Binary to denary

Task 4.3 Representing characters ... ITA2
Where we learn how computers use patterns to represent characters and symbols in ITA2

Load up the ITA2 encoding / decoding table

Click the image below to load up the International Telegraph Alphabet v2 (ITA2) encoding / decoding table and print yourself a copy of it using the print button at the top right.
Click to enlarge me and PRINT a copy out for your folder!


On the printed sheet ...

At the top of the printed sheet, make sure you put the following information ...
  • Name
  • Class
  • Today's date
... and underline everything with a pen and a ruler.

Decode the following strings

A string is a sequences of characters, in this case, represented by their ITA2 code. Sketch the fragment of tape on your paper (you might even be able to trace it from the screen if you teacher lets you!) and decode them using the character set shown in the table reading from left to right - write your translation underneath the sketch of the tape fragment.

Encode the following strings

Now it gets tricky! Get yourself a couple or three sticky notes and, using a piece of blutack and a sharp pencil, encode a simple 5 or 6 letter string (maybe your name) using ITA2. Write the string along the top edge of the sticky note, with the letters quite wide apart, and write dots to represent the sprocket holes. Remember to start your string with either a LETTERS or FIGURES character and end with a LINE FEED!

Write down your ideas

Try to answer the following questions on the sheet in full sentences. Using this strategy to analyse a situation is really useful - remember the 5W1H rule (can't think of a better description).
  1. What does ITA2 do well?
  2. Why might ITA2 not be used so much these days?
  3. How could you increase the number of characters in the character set?
  4. Who might have used this character encoding system?
  5. When (approximately) was the first message sent using ITA2?
  6. Where was Baudot code (ITA1) invented?

Task 4.4 Representing characters ... ASCII
Where we learn how computers use patterns to represent characters and symbols in ASCII

The ASCII system was invented in 1963 as an attempt to standardise the character encoding systems that were in use at the time. It was developed from the telegraph codes we have already learnt about.

Complete the following steps to help you learn more about ASCII.

Create a new word processed document

Create a new word processed document and make sure that ...
  • it's got a suitable filename;
  • it's saved in a suitable place;
  • it has a header with your name and class; 
  • it has a footer with pages numbers X of Y;
  • it has the title 'American Standard Code for Information Interchange (ASCII)';
  • the title is formatted in the 'heading 1';
  • it contains the same introduction as this task.

Compare your word processed document to mine

Does your word processed document look like mine?

If it's doesn't, go back to step one and try again. If you really get stuck, you can download a copy but your teacher will know you've done it (cause it's protected with a password and you can't edit it - lol).

Add an image of the ASCII table

Now, click on the following image to download yourself a copy (it will go into your downloads folder). I'll know that you've done this correctly (and not just copied and pasted) because the two images are different sizes and the smaller one has got a watermark on it - sneaky, eh!
You need to click this image to download and then insert it into the word processed document - don't copy and paste!

Write your first name in ASCII

Underneath the image, write a quick introduction to what you are doing and then encode your first name in ASCII. Remember, ASCII is actually the binary code, not the denary number so make sure you write down the binary, but you should put the denary code in brackets afterwards. This is what mine would look like ...

My first name encoded in ASCII

Print out your document for assessment

Make sure you have got your name on it. You'll be assessed on how closely your document resembles mine!
ASCII table

Task 4.5 Making decisions - Logic gates
Where we learn about simple logic gates

At a fundamental, electronic level, computer systems are built from tiny electronic devices called logic gates. We can get into the electrickery if you'd like, but suffice to say, when you combine these electronic devices in particular ways, magical things happen ...

Maybe you should!

Have a play with Scratch!

Click each of the images below in turn and investigate the operation of each logic gate.
Click each image to load it's Scratch project - refresh the webpage (F5) if it doesn't load correctly.

Tough Challenge - mini project on logic gates

Time for you to show some independence for the last part of the last task in this topic. Your challenge is to write up what you have discovered about the behaviour of logic gates and how they can be used to make logical decisions in real life situations.

You can use ...
  • The three Scratch Projects you have experimented with above;
  • A hidden slide on the topic presentation called 'The Secret Life of Logic Gates' - see if you can find it;
  • The World Wide Web.
You should ...
  • Present your work neatly;
  • Use tables if you can;
  • Add images if you can;
  • Provide references for any information you get from the web.

Print out your project

Make sure that you've put your name and class in the header and that you have put page numbers in the footer of your project and print this out for assessment.

Revision and End of Topic assessment
The default activity is a mindmap - click the badge to make one!

Your teacher will send you a link to the assessment

Still hungry?

Buy a Turing Tumble - a great game to play with your family to teach you how a computer works, but be careful that you don't lose the balls (they is very small!)
Click me to visit website!

Crash Course Computer Science - all 41 videos! If you've got a spare couple of days and don't mind having your mind blown, you might want to watch all / some / a few of the following YouTube videos.

This is an embedded playlist so if you click on the ...

... icon, you can choose a different video to watch if you like.