Abacus (2400 BCE) – Like a calculator, but uses beads that slide back and forth to get the answer.  You might see them in use today in San Francisco’s Chinatown.

Illustrate the origin of Abacus:
A long long time ago, a man named Lishou was responsible for keeping track of things for his village. As the number of things changed, he had a hard time calculating them. Lishou began mixing up the livestock population with the weight of the harvested grains. “We have 30 sheep. Last month, we received 8 lambs. Last week we ate 2 lambs. This week, 3 sheep died, but we received 5 more sheep from the neighboring village. Oh, I am confused. “ He said.

1642 – Mechanical Adding Machines – They could do addition and subtraction only and were the size of a large toaster. 

Illustrate this problem: “It takes so long to total the population of our country. I wish a machine could do it by itself.”

1890 – Hollerith Census Tabulator – A census is when all the people in a nation are counted. After the people are counted, the huge numbers must be added and analyzed. An early computer, perhaps the first real computer, was used to assist in this task.   

Illustrate this problem: “How can I calculate all the people in a nation, add them up, and analyze them?” (what is the sample used to analyze this country’s population?)

1941 - Zuse Z3 – The first “programmable” computer, meaning that you could give it instructions (like from a modern day keyboard) and it would act on them. 

Illustrate this:  The first “programmable” computer: “Computer, computer, 2 cups of lemon juices, plus 1 cup of sugar, how many cups of lemonade are in this litre flask?”

1951 – Mainframe Computer – The first truly large (the size of a bus) computers were built by a company called Univac.  They were used for census data (again) and complex financial transactions.  They used “batch” processing which means you load up all the data, push the button and the calculation starts…kind of like making a “batch” of cookies where you combine all the ingredients and put them in the oven. 

Illustrate this: “I am a computer, so smart that I can instantly do lots of things, such as design games, do all your math homework problems, count all the stars in the sky, recognize faces, play music, and etc.”

1972 – Desktop Computer – The smallest computer made so far with the keyboard, monitor and computer all in one machine the size of a breadbox.  These devices planted the seed for the personal computer that we see in our homes and libraries. 

Illustrate this: “My family is effective at losing weight. I am so small, you can take me home.”

1988 – Laptop Computers – Even smaller, more capable IC’s made it possible to perform even more complex operations on a computer the size of a thick magazine that you could put on your lap…from the 1951 computer (the size of a bus) to the much more capable laptop (the size of a thick magazine). 

Illustrate this: “Now I am not only smaller, but also smarter. My grandparents can’t talk with this human. But I can. Please poke my tummy, called a keyboard, and that thing called a mouse. Want to play a game?”

1999 – Gigahertz Processing – The increased speed of our computers makes it so we don’t have to wait long to download a game or movie. Gigahertz means that the computer can process 1 billion operations per second (that is one thousand times one million).

Illustrate this: “I am not only getting smarter, but also looks more beautiful. Look at the pictures, watch the videos. Do you agree?”