Activity 4.2 – Bits, Bytes, Boolean & Gates WebQuest                                                                                     

Purpose  

Jenny wanted to wash her parents’ car for some extra money. She got all the supplies she needed, attached the hose to the spigot, and put the spray nozzle on the end of the hose. First, she wet the car by turning on the water and pressing the nozzle handle. When she released the handle, the water stopped. She finished washing the car and reached for the nozzle to rinse off the soap, pressed the handle and nothing happened. Why wasn’t it working? Then she heard her little brother’s giggles. She went to the spigot and, sure enough, it was turned off. She remembered the discussion in class about logic gates and thought to herself the hose and spigot were like an AND gate. In order to have water coming out of the end of the nozzle, she had to “A” have the water turned on and “B” have the nozzle handle pressed.

Jenny was right about the water hose and nozzle being a lot like an AND gate. This activity is going to introduce you to logic gates and how they are used. You will be using this information to solve some digital problems later on, so pay close attention.

Equipment

-    Computer with internet access

Procedure

1.      Go to http://www.howstuffworks.com/.

2.      Make the query [search] for “Electronic Gates.” Select the article “How Electronic Gates Work.” Use it to answer the following questions:

[A] Before modern electronics, relays and later vacuum tubes were combined to form the Boolean Logic Gates used in computers. In 1947, _______________ were invented. Once they were perfected, they replaced vacuum tubes in computers. transistors 2. Setting the Stage, paragraph 2, http://electronics.howstuffworks.com/digital-electronics1.htm

[B]It took several transistors, resistors, and diodes to create one Boolean Logic Gate. These gates were assembled using discrete components. That is, each component was a separate device. Then in the 1960s came _____________. integrated circuits 3.  Setting the Stage, paragraph 3, http://electronics.howstuffworks.com/digital-electronics1.htm

[C]First, there were SSI IC’s which stands for ___________________________. small scale  4. Setting the Stage, paragraph 3, http://electronics.howstuffworks.com/digital-electronics1.htm integration

[D]these contained approximately ____ transistors to form ____ logic gates. 20, 4 to 6 5. & 6. Setting the Stage, paragraph 3, http://electronics.howstuffworks.com/digital-electronics1.htm

[[E] As manufacturing techniques improved, integrated circuits were built containing more and more transistors. [DO NOT NEED ANSWER]

[F] Today, VLSI IC’s contain as many as _____________ transistors. 20 million  7. Setting the Stage, paragraph 4, http://electronics.howstuffworks.com/digital-electronics1.htm

[G] VLSI stands for ___________________________. very la  rge scale integration 8. Setting the Stage, paragraph 4, http://electronics.howstuffworks.com/digital-electronics1.htm

3.      Make the query “Bits and Bytes.” Select the article “How bits and bytes work.” Use it to answer the following questions:

[A] What number system do computers operate on? Decimal-binary number Last paragraph, http://computer.howstuffworks.com/bytes.htm

[B] Describe the term bit. Binary Digit Second paragraph, http://computer.howstuffworks.com/bytes1.htm

[C] Describe the term byte. 8 Bit Collections Under table of #'s 1-20, 2nd paragraph, http://computer.howstuffworks.com/bytes1.htm

[D] What are the possible values of a bit? 0 or 1 Second paragraph, http://computer.howstuffworks.com/bytes1.htm

4.      Make the query “Boolean Logic.” Select the article “How Boolean Logic Work.” Use it to answer the following questions:

[A] The inverter gate is also called a ___ gate. NOT Under Simple Gates, second paragraph, http://computer.howstuffworks.com/boolean1.htm

[B] Describe what an inverter does. It takes one bit as input and produces as output its opposite. Under Simple Gates, second paragraph, http://computer.howstuffworks.com/boolean1.htm

-    Fill in the table below to describe the operation of an inverter.

*This is done for you as an example for the other gates Opposite output of the input Picture of NOT Gate, http://computer.howstuffworks.com/boolean1.htm

[C] Why is the output identified with the letter Q rather than O? ("used for the output because if you used "O," you would easily confuse it with zero). First paragraph under the NOT Gate picture, http://computer.howstuffworks.com/boolean1.htm

*In the description table write out in words what the numbers represent from the Inverter table 'A, Q' for each row.

Inverter Schematic Symbol

[please draw in your notebook]

You Should Only Have Needed to Highlight Page IF You Couldn't Find the Answers in the Reading!!!

[D] Describe what an AND gate does. The AND gate performs a logical "and" operation on two inputs, A and B Paragraph 4 in 'BOLD', http://computer.howstuffworks.com/boolean1.htm

[E]  Fill in the table below to describe the operation of an AND gate and describe what each row means.

("Q" is used for the output because if you used "O," you would easily confuse it with zero).

*In the description table write out in words what the numbers represent from the AND table 'A, B, Q' for each row.

AND Gate Schematic Symbol

[please draw in your notebook]

[F] Describe what an Or Gate does.

-    Fill in the table below to describe the operation of an Or Gate and describe what each row means.

*In the description table write out in words what the numbers represent from the OR table 'A, B, Q' for each row.

OR Gate Schematic Symbol

[please draw in your notebook]

[G] Describe what an XOR gate does.

-    Fill in the table below to describe the operation of an XOR Gate and describe what each row means.

*In the description table write out in words what the numbers represent from the XOR table 'A, B, Q' for each row.

XOR Gate Schematic Symbol

[please draw in your notebook]

[H] The Exclusive OR Gate is actually a combination of which two other logic gates?

Conclusion

C1.      What is the difference between a bit and a byte?

C2.      What purpose do logic gates serve?

C3.      Are there different ways to achieve the same results using different logic gate combinations?