CHAPTER INVESTIGATION
Design an Electronic
Communication Device
OVERVIEW AND PURPOSE
The telegraph was one of the first
inventions to demonstrate that
machines could be used to communicate over long distances.
In a telegraph, messages are sent as electrical signals along a
wire from a sending device to a receiver.
Like modern computers, the telegraph uses a binary code.
The code is called Morse code—a combination of short and long
signals—to stand for letters and symbols. In this lab, you will use
what you have learned about circuits to
• design a battery-powered device that uses Morse code
• build and test your design
Problem
MATERIALS
• 2 batteries
• light bulb in holder
• piece of copper wire
• 2 wire leads with
alligator clips
• 2 craft sticks
• toothpick
• paper clip
• piece of cardboard
• clothespin
• aluminum foil
• rubber band
• scissors
• tape
• wire cutters
• Morse Code Chart
398 Unit 3: Electricity and Magnetism
A toy company has contracted you to design and build a new
product for kids. They want a communication device that is
similar to a telegraph. Kids will use the device to communicate
with each other in Morse code. The company’s market research
has shown that parents do not like noisy toys, so the company
wants a device that uses light rather than sound as a signal.
Procedure
Brainstorm ideas for a communication device that can use Morse
code. Look at the available materials and think how you could
make a circuit that contains a light bulb and a switch.
Describe your proposed design and/or draw a sketch of it in your
Science Notebook. Include a list of the materials that you
would need to build it.
Show your design to a team member. Consider
the constraints of each of your designs, such as
what materials are available, the complexity of the
design, and the time available.
Conclude
Write
It Up
1. EVALUATE What problems, if any, did you
encounter when testing your device? How
might you improve upon the design?
Choose one idea or combine two ideas into
a final design to test with your group. Build a
sample version of your device, called a prototype.
2. IDENTIFY LIMITS What are the limita-
Test your device by writing a short question.
Translate the question into Morse code. Make
long and short flashes of light on your device
to send your message. Another person on your
team should write down the message received
in Morse code, translate the message, and send
an answer.
3. APPLY How might you modify your design
Complete at least two trials. Each time, record
the question in English, the question in code, the
answer in code, and the answer in English.
Write a brief evaluation of how well the signal
worked. Use the following criteria for your
evaluation for each trial.
• What errors, if any, occurred while you
were sending the signal?
• What errors, if any, occurred while you
were receiving the signal?
• Did the translated answer make sense?
Why or why not?
Observe and Analyze
Write
It Up
1. MODEL Draw a sketch of your final design.
Label the parts. Next to your sketch, draw a
circuit diagram of your device.
2. INFER How do the parts of your circuit
allow you to control the flow of current?
3. COMPARE How is the signal that is
used in your system similar to the digital
information used by computers to process
information? How does the signal differ?
4. APPLY A small sheet of instructions will be
packaged with the device. Write a paragraph
for the user that explains how to use it. Keep
in mind that the user will probably be a child.
tions of your design? You might consider its
estimated costs, where and how kids will be
able to use it, and the chances of the device
breaking.
so that it could be used by someone with
limited vision?
4. SYNTHESIZE Write down the steps that
you have used to develop this new product.
Your first step was to brainstorm an idea.
INVESTIGATE Further
CHALLENGE Design another system of
communication that uses your own code. The
signal should be in the form of flags. Make a
table that lists what the signals mean and write
instructions that explain how to use the system
to communicate.
ation Device
onic Communic
Design an Electr
nalyze
Observe and A
e Testing
Table 1. Prototyp
Trial 2
Trial 1
Question
(English)
Question
(code)
Answer
(code)
Answer
(English)
Evaluation
Conclude
Chapter 11: Circuits and Electronics 399