Current Electricity

Objectives:

Plasma :)

• Know how to construct simple circuits, using cells and bulbs.

• Be able to explain what is meant by voltage, current and resistance.

• Know how changes in voltage or resistance will affect the current flowing in a circuit.

Task 1 - Starter

Think hard!

Looking good!

Find someone who knows:

• What is a conductor?

• What is an insulator?

• What are the two types of charge?

• Which type of charge is small and light?

• How can insulators become charged?

• What causes static shocks?

• What do the terms static and current mean?

Your teacher will ask you to share your ideas with the class, and may write some of your ideas, suggestions, and comments on the board.

Task 2 - Voltage, Current & Resistance

Some leads.

Collect the following apparatus:

• 2 cells

• 2 bulbs

• 4 leads.

Try the challenges below. Record your findings on this worksheet.

Challenge 1

Lightbulbs. Yeah!

Use one cell, one bulb, and as many leads as you need.

Can you make the bulb light up?

Discuss in your group:

• What is the role of the cell?

• What is happening in the wires/leads?

• How does the bulb work?

Your teacher will ask you to share your ideas with the class, and may write some of your ideas, suggestions, and comments on the board.

Your teacher may explain these ideas using the simulation below.

Explaining ideas - Circuit Construction Kit simulation

This simulation shows us what is happening inside the circuit.

Click to Run

Click the image to load the simulation.

Thanks to PhET for this awesome simulation :)

Java technology!

Challenge 2

A quad loop carbon filament lamp.

How can you make your bulb brighter?

Discuss in your group:

• Has the voltage in the circuit changed?

• Has the current flowing changed?

• Has the resistance in the circuit changed?

• Did you encounter any problems building your circuit?

Challenge 3

Lightbulbs.

Can you add a second bulb to your circuit, using only one extra lead?

Discuss in your group:

• What differences do you notice?

• Has the voltage changed?

• Has the current flowing in the circuit changed?

• Has the resistance changed?

Extension

Vintage lightbulbs.

Pretty :)

1. Unscrew one of the bulbs in your circuit. What happens to the other bulb? Can you explain why?

2. Build a circuit with two bulbs and two cells; the second bulb must stay lit, even if the first bulb breaks or is unscrewed.

You will need five leads for this circuit. Draw a diagram of your circuit - if you succeed!

Task 3 - Key terms

Wise words from Einstein.

Working in pairs or threes, come up with a sentence to explain what is meant by:

1) Voltage

2) Current

3) Resistance

You may want to write your sentences in your exercise books.

Task 4 - Explaining your ideas

Electricity arcing.

Describe what is meant by current electricity and how a simple electrical circuit works, using ideas from the previous tasks.

Try to include these keywords in your explanation:

cell bulb filament voltage charges current flow energy transfer resistance

Task 5 - Demonstration

A rocker switch.

Nice.

Switches can be used to control the flow of current in a circuit.

Your teacher will demonstrate several types of switch to you:

• push-to-make switches

• push-to-break switches

• toggle switches

• two-way switches