# Natural Science - Year II

#### Unit 51 Lab: Simple Ciruits

Unit 51 Lab: Simple Circuits

 This Unit's Homework Page History Lecture Science Lecture Lab Parents' Notes

# Unit 51 Laboratory Activity: Building Simple Electrical CircuitsOR Mapping a Magnetic Field

## Goal: Build series and parallel circuits

Materials:

### Materials

• An AA or AAA battery.
• You can also build your own battery, for which you will need
• A lemon or lime
• A copper screw (2" or 5cm long) or insulated copper wire
• A zinc screw (2" or 5cm long)
• Insulated wire.
• Two or more holiday lights capable of carrying a 2amp current. Cut the wires leading to the bulb so that you have input and output leads and the socket to hold the bulb, as well as a working bulb.

### Procedure:

1. Roll the lemon or lime in your hand to soften the skin, but do not break the skin.
2. Insert the zinc screw into the lemon. Be sure that it touches the liquid pulp inside but does not poke through the opposite side of the fruit.
3. If you are using copper wire for your second lead, remove about 1" (2.5cm) of insulation from the end of the wire.
4. Insert the copper screw or end of the copper wire into the lemon.
Building a simple series circuit
1. Remove some of the insulation from the wire leads on the lamp. Do not cut the wire itself.
2. Connect one of the wires from the lamp around the negative terminal (zinc screw).
3. Connect the other lead wire of the lamp to the positive terminal (copper screw, or to your copper wire).
4. Is your holiday lamp glowing? If not, check the bulb to make sure that it is not burned out, then check the wiring for lose connections.
5. Disconnect one of the lamp leads from the negative terminal of the battery.
6. Connect one lead from the second lamp to the now-open negative terminal from the battery.
7. Connect the other end of the second lamp to the disconnected leads of the first lamp to make a series circuit of two lamps.
8. Note whether your lamps are brighter or dimmer than when you only had one lamp in the circuit.
9. What happens if you remove one of the bulbs from its socket?
Building a simple parallel circuit
1. Connect one lead from one lamp to the positive (copper screw) end of your battery.
2. Connect the second lead from on lamp to the negative (zinc screw) end of your battery.
3. If the light is not glowing, check your bulbs for burnout and your leads for loose connections.
4. Note how bright the single light is.
5. Connect the second lamp exactly as you did the first lamp. You should now have two bulbs in parallel.
6. How bright are the lights compared to when you had only one bulb connected in the parallel circuit?
7. What happens if you remove one of the bulbs from its socket?
Report
1. Draw a picture of your circuit.
3. What are one advantage of parallel circuit? of a series circuits? What is a disadvantage of each?

## Goal: To map a magnetic field

Materials:

• Setup from Electrical Circuit Lab
• Iron filings or compass
• Two pens or pencils with different colors
• White paper
Procedure:
1. Establish the earth's magnetic field
2. Using Iron Filings:
1. Pour about 1/2 teaspoon of iron filings onto the paper and spread them evenly.
2. Draw the lines marked out by the iron filings on the paper using a light-colored pen or pencil.
3. Using a compass:
1. Put the compass in different positions on the paper. At each position, mark location of the north and south end of the compass arrows on the paper, then draw a line from the north to the south end using your light-colored pen or pencil.
4. Set up your series circuit with one bulb.
5. Using Iron Filings:
1. Pour about 1/2 teaspoon of iron filings onto the paper and spread them evenly.
2. Extend your conducting wire and bulb above the filings, but do not rest the wires on the paper (you may short out your circuits if the iron filings get into the connections). Draw the lines marked out by the iron filings on the paper using your darker-colored pen or pencil.
6. Using a compass:
1. Lay the circuit wire on the paper.
2. Put the compass in different positions near the wire. At each position, mark location of the north and south end of the compass arrows on the paper, then draw a line from the north to the south end using your darker-colored pen or pencil.
Report
1. Save your drawings. Scan them or describe them verbally.
2. Does the presence of a current-carrying wire change the magnetic field?
3. What direction does the field around the wire take?