Lesson 4

Why are wires metal on the inside and coated with plastic on the outside?
Build your own circuit to find out.
Which materials let electrons flow freely and which do not?

1 What did you do last time? 2 buzzer load closed PRINT one of these words next to
the matching image on the next slide.
loop battery opened switch motor
E-lesson 4 bat ope mot buz loa swi
4 Remember: Electrical current flows through the closed loop. OPEN CLOSED 5 Does electrical current flow through everything?
Let's find out.
When you are ready, go to the next slide.
6 Find these items in your kit: battery
bulb 1.5 Volt
buzzer alligator
7 Make a loop, but this time add in an extra test lead. 1 The wires with alligator clips
are called test leads.
2 Touch and then separate the red and yellow
alligator clips. What happens?
8 Bite a copper penny with the two alligator leads. 3 NOTE: Be sure the the two alligator clips DO NOT touch each other.
If they do touch, the light will shine
NO MATTER what you put into the circuit.
Did the light shine?
9 ? Remove the penny.
Test the objects
in your kit.
4 Test other objects around your house. Separate the things that conduct electricity
from the things that don't.
10 What kinds of objects
11 Metals conduct electricity. 12 INSULATORS The crayon doesn't
conduct electricity.
The wax in the crayon is an insulator.
The craft stick does not conduct electricity. Wood is an insulator. The rubber band
does not conduct
electricity. Rubber
is an insulator.
The coating
on the wire is an
insulator too.
Most non-metals do not conduct electricity BUT some do. Materials that do not conduct electricity are called:
13 Select to Play. 14 Conductors and Insulators 15