What do computers look like?

Suitable for Year Levels 7–10

Think Ahead is home to an important piece of Australian innovation. CSIRAC stands for the Commonwealth Scientific Industrial Research Automatic Computer. When it was switched on in 1949, it was the first computer in Australia, the fourth computer in the world and would become the first computer in the world to play music. If you were asked to draw a computer today however, it probably wouldn’t look like CSIRAC. You might have drawn a desktop computer or a laptop, or maybe a smartphone. Computers have changed a lot in the past 100 years. What do you think computers of the future will look like?

Research CSIRAC

This graphic is from the Think Ahead exhibition. Click on the image to enlarge it.

Graphic timeline of computers
Graphic timeline of computers

Watch this video about CSIRAC made for its 50th anniversary in 1999 when it first went on public display at Melbourne Museum. In 2018, CSIRAC moved to Think Ahead at Scienceworks.

Comparing CSIRAC to modern devices

While CSIRAC was a noisy, power hungry machine that filled a room, you can now fit a computer more than a million times more powerful inside your pocket.

Fun facts CSIRAC, 1949–1964 Smartphone, 2020
Processing speed 1000 hertz 2,960,000,000 hertz
Storage/memory capacity 2000 bytes 274,877,906,944 bytes
Size 40 square metres 0.01 square metres
Weight 2,500,000 grams 200 grams
Power usage 30,000 watts 6 watts when charging
Hardware technology 2000 valves

4,300,000,000 silicon transistors


  • “My phone uses only ___% of the power that CSIRAC needed to run.” (Don’t forget to multiply by 100 to get the percentage!)
  • “CSIRAC was huge! It was ___ times the size of my bedroom.” (You’ll have to measure how many square metres your room is).
  • “CSIRAC weighs as much as ___ elephants, whereas my phone is like carrying around (insert small animal that weighs the same as your phone).”
  • “The amount of memory CSIRAC could store was like (find out what could be saved with 2KB).”

What’s still the same about computing?

Even though modern computers are vastly faster, smaller and more powerful than CSIRAC, at the most basic level there are still some similarities. CSIRAC used electric valves to represent information in a binary bit: 1 for when the circuit was on and 0 for when the circuit was off. Silicon transistors in today’s computers still represent information in binary as 1 for on and 0 for off - there are just billions more of these switches! The more transistors there are, the more information can be manipulated. The more transistors we can fit on a computer chip, the more powerful and portable a computer can be.

Electronic Valve
Electronic Valve - AWV, Dual triode, Type 6SN7GTA, 1960s
Detail of a computer motherboard


While we need ten different digits (0,1,2,3,4,5,6,7,8,9) to be able to count the way we do, it’s much easier for computers to be able to count with just two digits (0,1) as you can use an electric switch turning on or off to physically represent that. The way we count, we can use the first place value to represent any number from 0 to 9, however if we want to say the next number bigger than that we have two use two place values to say 10 (1 ten and 0 ones). While decimal place values go up in multiples of 10 (100, 1000, 10,000 etc), binary place values go up in multiples of 2.

Binary place values

  • What’s the biggest number you can represent with one place value in binary?
  • How do you represent two in binary?
  • What number does 11101 represent?
  • A byte is eight binary bits, what’s the highest value number you can represent with a byte and how do you write it in binary?
  • CSIRAC had around 2000 bytes of storage. How would you work out the largest number that can be represented with 2000 bytes?

Of course, this is just a start to how numbers are represented in binary. Computers also represent words, colours, sounds which are all encoded at machine level in binary too! What’s the simplest way you can think up to represent letters and words in binary? Once you’ve done that, send someone a secret message and see if they can crack your code!

Keep an eye out on the Scienceworks Learning page for more CSIRAC activities coming soon!

Victorian Curriculum Links

Digital Technologies

Data and Information Level 7 & 8

  • Investigate how digital systems represent text, image and sound data in binary (VCDTDI036)
  • Acquire data from a range of sources and evaluate their authenticity, accuracy and timeliness (VCDTDI037)

Digital Systems Level 9 &10

  • Investigate the role of hardware and software (VCDTDS045)


Number and Algebra Level 7 & 8

  • Express one quantity as a fraction of another, with and without the use of digital technologies (VCMNA245)
  • Connect fractions, decimals and percentages and carry out simple conversions (VCMNA247)
  • Find percentages of quantities and express one quantity as a percentage of another, with and without digital technologies. (VCMNA248)
  • Recognise and solve problems involving simple ratios (VCMNA249)

Number and Algebra Level 9 & 10 

  • Express numbers in scientific notation (VCMNA303)

Measurement and Geometry Level 7 & 8

  • Establish the formulas for areas of rectangles, triangles and parallelograms and use these in problem solving (VCMMG258)

Measurement and Geometry Level 9 & 10

  • Calculate the areas of composite shapes (VCMMG312)


Science as a human endeavour Levels 7–10

Science Inquiry Skills, Communicating Level 7 & 8

  • Communicate ideas... using appropriate scientific language and representations (VCSIS113)


Historical significance Level 7 & 8

  • Evaluate the role and achievement of a significant individual, development and/or cultural achievement that led to progress (VCHHC104)

Historical significance Level 9 & 10

  • Evaluate the historical significance of an event, idea, individual or place (VCHHC128)

The modern world and Australia Level 9 & 10

  • Changing social, cultural, historical, economic, environmental, political and technological conditions on a major global influence in Australia (VCHHK159)

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