Download Table of Contents

Table of Contents
Career Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Basic Lesson Plans
Activity 1 – ElectroLight Battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Activity 2 – Lights and Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Activity 3 – Ohm’s Law. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Challenge 1 – Holiday Light Manufacturing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Activity 4 – Electronic Schematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Activity 5 – Breadboarding Blinky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Activity 6 – PCB Blinky. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Activity 7 – Breadboarding the Show. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Challenge 2 – PCB Laser Light Show. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Standards Addressed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Puzzle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Links of Interest. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3
Activity 2
Lights and Switches
Teacher Procedure
Objective
Procedure
1
2
In this activity, students investigate series and
parallel circuits while collecting data.
Instruct students to get into teams of two.
Background
Have students follow the Student Procedure
to build a series circuit from three
lightbulbs, a switch, and a power supply; to use
a multimeter to measure the voltage; to build a
parallel circuit; and to complete the “Lights and
Switches Data Sheet.”
The terms series circuit and parallel circuit
refer to the way that a circuit is connected. A
series circuit is a series of components hooked
together along a single path. The current
that flows through the first component will
be the same current that flows through each
component.
Traditionally, this was how holiday lights were
strung. That’s why the entire strand went off
when one lightbulb quit working. That one
bad lightbulb created an open circuit so the
current could no longer flow. The hard part
about a string of lights not working is that it’s
difficult to tell which bulb is bad. Eventually, the
manufacturers got smart and began producing
holiday lights in a parallel circuit configuration.
Parallel circuits are wired in such a way that
if one bulb goes out the other bulbs will still
shine.
11
Activity 2
Lights and Switches
Student Procedure
3
4
5
Vocabulary
•
•
•
•
•
•
•
Next, cut three pieces of wire each three
inches long. Strip the ends.
closed circuit
current
open circuit
parallel circuit
series circuit
switch
voltage
Locate the battery holder, batteries, and
knife switch.
Loosen the screws on each socket holder
and the knife switch. Do not allow the
small nut to fall off the socket screw.
Materials
•
•
•
•
•
•
•
•
•
•
•
•
3 lamp sockets (Pitsco product 59391)
3 – 1.5V bulbs (Pitsco product 59392)
Knife switch (Pitsco product 59395)
Electrical wire (Pitsco product 56142)
Scissors
Wire stripper
Ruler
Small Phillips and flat-head screwdrivers
Multimeter
4 AA battery holder (Pitsco product 32971)
4 AA batteries
“Lights and Switches Data Sheet”
6
A series circuit is similar to making a
complete circle. Using the wire you cut,
string the lights, switch, and battery holder
(power source) together to make a complete
circle (circuit). Hook the red wire of the battery
holder to the right side of the switch. Hook the
left side of the switch to the right side of the first
bulb. Hook the left side of the first bulb to the
right side of the second bulb, and so on. Your
last connection should be connecting the black
wire of the battery holder to the left side of the
third bulb.
Procedure
1
2
Get into teams as instructed by your
teacher.
Build a series circuit using three lightbulbs,
a power source, and a switch. First, locate
the three lamp sockets and 1.5V bulbs. Screw
the bulbs into the lamp sockets.
12
Activity 2
Lights and Switches
Student Procedure
7
a complete circuit. Hook the red wire of the
battery holder to the right side of the switch.
Hook the left side of the switch to the right side
of the first bulb. Hook another wire into the
right side of the first bulb and connect it to the
right side of the second bulb. Then, another
wire should connect the right side of the second
bulb to the right side of the third bulb. The left
side of the third bulb should connect to the
right side of the second bulb and then connect
to the right side of the first bulb.
Open the knife switch (creating an open
circuit) and load the batteries into the
battery holder. Close the switch and watch the
lights illuminate.
8
9
With the series circuit lights on, locate the
multimeter. Set it to 20V.
In the series circuit, the current is only
flowing in one direction (DC, or direct
current). You can tell the direction of current
flow by placing the red lead on one side of a
lightbulb and the black lead on the other side
of the same bulb. If the multimeter reads a
negative number, the current is flowing in the
other direction.
10
Following the instructions on the
“Lights and Switches Data Sheet,”
fill out the series circuit measurements table.
Disassemble the series circuit.
13
The last connection should be
connecting the black wire of the battery
holder to the left side of the third bulb. Close
the switch and watch the lights illuminate.
11
Now construct a parallel circuit using
three lightbulbs, a power source, and a
switch. Cut two more three-inch pieces of wire.
Strip the ends.
14
15
With the parallel circuit lights on, locate
the multimeter. Set it to 20V.
12
Following the instructions on the
data sheet, fill out the parallel circuit
measurements table. Complete the rest of the
data sheet.
A parallel circuit is similar to having
different choices in a traffic jam. If
there is an accident on A Street, you can use
B or C streets to get to the destination. Using
the wire pieces, string the lights, switch, and
battery holder (power source) together to make
13
Activity 2
Lights and Switches
Student Procedure
Lights and Switches Data Sheet
Series Circuit Measurements
Measure the voltage of the battery pack, across each lightbulb, and across the switch in both the
open and closed positions.
Voltage off
Voltage on
Battery pack
Lightbulb 1
Lightbulb 2
Lightbulb 3
Add the voltages that are across the three lights when they are turned on.
In a series circuit, voltages added across the three lightbulbs should equal the same voltage the battery pack held. Was this true in your circuit? If not, what do you think caused the difference?
What caused the changes in voltage across the switch?
Unscrew Lightbulb 1. What happens to the other lights? What is the voltage across Lightbulb 1?
Lightbulb 2?
Lightbulb 3?
Screw Lightbulb 1 back in place. What do you think would happen if you unscrew Lightbulb 2 or 3?
Try it and see what happens.
What can you conclude about a lightbulb burning out in a series circuit?
14
Activity 2
Lights and Switches
Student Procedure
Lights and Switches Data Sheet continued
Parallel Circuit Measurements
Measure the voltage of the battery pack, across each lightbulb, and across the switch in both the
open and closed positions.
Voltage off
Voltage on
Battery pack
Lightbulb 1
Lightbulb 2
Lightbulb 3
Unscrew Lightbulb 1. What happens to the other lights? What is the voltage across Lightbulb 1?
Lightbulb 2?
Lightbulb 3?
Screw Lightbulb 1 back in place. What do you think would happen if you unscrew Lightbulb 2 or 3?
Try it and see what happens.
What can you conclude about a lightbulb burning out in a parallel circuit?
According to your measurements, what is the biggest difference between a series circuit and a parallel circuit?
If you have a string of holiday lights (series circuit) on your house, what happens if a lightbulb burns
out? Why?
If you have a string of holiday lights (parallel circuit) on your house, what happens if a lightbulb
burns out? Why?
Is it an advantage or disadvantage to purchase lights strung in series?
Is it an advantage or disadvantage to purchase lights strung in parallel?
15
Glossary
battery – an energy storage device
breadboard – a solderless way to connect components or build a prototype
soldering – a process that joins two pieces of
metal
capacitor – a device used to temporarily store
electric charge
switch – an electronic component that can
break or interrupt a circuit (turn a circuit off and
on)
closed circuit – a continuous circuit
trace – the electrical connections on a PCB
cold solder joint – a bad solder joint
transistor – a device similar to a switch that is
open and has no moving parts
conductor – a wire or component that conducts
electricity
current – the electricity that flows through a
circuit
electrodes – the copper and zinc elements in a
battery
voltage – a unit of measure for power in a
circuit
voltage regulator – an electrical component that
regulates or maintains the voltage at a constant
level
electrolyte – the acid solution in a battery
LED – light emitting diode; an indicator light in
a circuit
ohm – a unit of measure for resistance
Ohm’s law – Ohm’s law states the current
through a conductor is directly proportional to
the potential difference or voltage across it and
inversely proportional to the resistance.
open circuit – a circuit that is not continuous
and through which no current is flowing
parallel circuit – a side-by-side way of connecting components so that the ends of each component are connected together
PCB – a printed circuit board
potentiometer – a variable or adjustable resistor
resistor – a device that resists the flow of electricity
schematic – a diagram that shows a circuit using symbols to represent components
series circuit – a way of connecting components
one after another so that the same current flows
through each one
69