Lesson 3

Can you build a switch with one paper clip?
Open and close your own circuits. Take control!
Send coded messages with sound. Decode secret messages.

1 What did you do last time? 2 buzzer load LED PRINT one of these words next to
the matching image on the next slide.
loop battery wire bulb motor
3
E-lesson 3 led bat mot buz loa wir
4 When the loop is OPEN the bulb is out. Electrical current flows through the closed loop. OPEN When the loop is CLOSED the light shines. CLOSED 5 Let's build a switch
to open and close a circuit loop.
When you are ready, go to the next slide.
6 Find these items in your kit: battery
band
motor 1.5 Volt
battery
alligator
leads
buzzer switch
card
paper
fastener
paper clip
7 Push the paper fasteners through the two holes
in the switch card.
Turn over the switch card and push one fastener through the paper clip. 1 2
8 Bend open the
paper fastener.
3 4 Connect an alligator clip to each paper fastener.
9 Connect the switch to the motor. 5 Push the paper clip against the brass paper fastener to close the loop and turn on the motor. 10 6 Now you can send coded messages to a friend. Try one beep for YES
and two beeps for NO.
Insert the buzzer in place of the motor.
11 Samuel Morse made a simple code for the alphabet to send messages over long distances
before there were telephones.
Morse Code DI - a short beep, written as a short dot (.) DA - a long beep, written as a long line (_)
12 SOS {DI DI DI} {DA DA DA} {DI DI DI}
(short short short) (long long long) (short short short)
S . . .
O _ _ _
S . . .
SAVE OUR SHIP
13 This message is
in Morse code.
Decode it,
letter by letter.
Morse Code
14