Background and Introduction | It's as Easy as 1, 2, 3 | Modeling a Computer Search Algorithm | Circuit Boards
Camp-In Curriculum: Computers
Campers explore how software communicates instructions to a computer, and how hardware controls the flow of electrical signals.
One of the first calculating tools, the abacus, was developed thousands of years ago. Computers use the same principles as the abacus to perform arithmetic, except instead of pushing beads along dowels, computers use electrical signals. This code of electrical signals is based on the idea that information can be represented with only two digits, 1(on) and 0 (off). This is called binary code. The first system of binary numbers was introduced in the 1600s. Like many scientific discoveries, binary numbers were first proposed to solve theoretical problems. Practical applications came later.
In the 1830s Charles Babbage, a British inventor, conceived of a machine that could be given instructions to perform different tasks and store results, which he called the Analytical Engine. Ada Byron, also known as Lady Lovelace, learned about Babbage's work, corresponded with him, and added her own ideas. In 1843 she published an article predicting that such a machine might be used to compose music, produce graphics, and do scientific work. Ada suggested a plan for how the engine might calculate Bernoulli numbers. This plan is now regarded as the first "computer program."
The first electronic computer was built in the twentieth century. During World War II, the US government needed to solve large complex problems. In the early 1940s, computers used electromechanical relay switches. Instructions were translated into binary code, and transmitted as punched holes in reels of paper. Punched holes were 1s and were read as ON, allowing current to flow through the paper. Zeroes were covered and read as OFF, and the current would not flow through the paper. Although this was laborious work, once the computer was programmed, repeated computations could be performed quickly.
In 1945, at the Moore School of Engineering at the University of Pennsylvania, the Electronic Numeric Integrator and Computer (ENIAC) was developed. Its assignment was to calculate rapidly the complicated ballistic tables used to aim weapons accurately. By converting numbers into digital code which could be easily manipulated, ENIAC operated 10,000 times faster than mechanical devices. However, the ENIAC used thousands of vacuum tubes and was so huge that it filled a building the size of a gymnasium.
Until the mid 1950s all electronic devices used vacuum tubes. Failures were frequent because of the limited lifetime of the heating filaments and massive power requirements of the tubes. The invention of the transistor in 1947 by John Bardeen, Walter Brattain, and William Shockley revolutionized electronics. The transistor became an ideal substitute for the vacuum tube for most purposes, because it was more reliable, required much less power, and produced little heat. Transistors enabled computers to become smaller and more efficient, yet with greater complexity of design. By 1959 practically all computer manufacturers used transistors. During the 1960s transistors displaced vacuum tubes in television sets and radios.
The next important step in computer history was the integrated circuit, developed independently by Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor. Electronic elements and connections are embedded on a small wafer of silicon. Several transistors can be placed on one chip, increasing miniaturization and reliability by decreasing the number of components to be placed on a printed circuit board. The greatest breakthrough in chip technology came during the early 1970s with the introduction of the first computer memory chips and microprocessor chips, heralding the development of the microcomputer a few years later.
The development of computers and digital electronics can be termed a technical revolution. Computers progressed from cumbersome electronic renderings of electromechanical machines to highly flexible and user-friendly machines. Their application spread from "number crunching" into all areas of human activity. Software -- nonexistent when the first computers were built -- developed quickly. Today we use computers to organize words, numbers, and pictures in our homes, schools, offices, stores, theaters, baseball parks, and cars.
The parts of a computer
To perform a task, a computer first needs input. The keyboard is the most common input device. A scanner or video camera can deliver information and images to a computer. The computer then interprets and carries out instructions, receives, sends, and stores information using circuit boards. Computers store the programs and files in their memory. Disks store information in magnetic patterns which can be used to manipulate electric current.
Output is the text, picture, graph or sound that is returned after it is processed. The visual monitor is the most common output device. A printer puts information onto paper.
Finally, computers need software. Software or computer programs are lists of instructions written by a person that tell a computer what to do. Software is stored as a set of electromagnetic code signals in the computer's memory, on a disk or microchip.
Software and hardware designed to send and receive data allow computers to share information with other computers and people around the world. Modems translate computerized data into signals that travel through phone lines.
Benchmarks for Science Literacy 
Activity: It's as Easy as 1, 2, 3
Background for Instructors
In this activity, participants will try to break down the everyday task of putting on a jacket into simple step-by-step instructions that a computer robot could understand. It's not as easy as it seems!
This activity demonstrates a similarity between computer mechanics and biology. Specificity and accuracy of information is important in genetics as well as in computers. DNA transmits complicated yet precise instructions to make new cells. In cells, just as in computers, confusion or mutation results when instructions are rearranged or deleted.
Activity -- Modeling a Computer Search Algorithm
Background for Instructors
Students act out two search methods. One is simple, but usually slow. The second is more complex, but usually fast. The first program checks each member of the group in sequence to see who has the designated number. In a group of one million members, you would need on average 500,000 checks to find one member. In the second search method, the group is halved at each step. Finding a single member in a group of one million will take at most 20 checks.
Computer search algorithms are used every time you "spell check" a report or call directory assistance for the telephone number of your favorite restaurant.
(For clarity in describing these procedures assume there are 15 people in this group.)
Experiment -- Circuit Boards
Background for Instructors
In this activity campers construct circuit boards using short strips of wire or foil hidden behind a tray to connect metal brads. When the matching brads are connected with wires to a battery and bulb, a circuit is completed and the bulb lights. Campers can then use their circuit testers as "quiz boards" to find matching pairs.
This activity makes more sense if campers have already constructed working battery, wire, and bulb set-ups. If, due to logistical constraints, some participants are making their circuit boards prior to experimenting with circuits, it may be helpful to set up some circuit "testing stations" ahead of time.
You can use the sample "quiz" sheet included here or campers can use the blank template to create their own quiz questions. Try matching sports teams with their cities, or words in English with words in Spanish, or animals with the foods they eat. It is helpful to have a template showing where to insert the brads.
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