§12.1 & 12.2 Potential Difference

• Science
• Upper Secondary (Key Stage 4)

§12.1 Batteries and Cells

&

§12.2 Potential Difference

Science - TTO2

Learning Objects §12.1

• Recognise the significance of the value of the ‘emf’ of a battery. 
  
• Recall electromotive force (emf) is measured in volts.
  
• Describe how to use a voltmeter to measure the emf of a battery or a potential difference in a circuit.
  
• Explain the significance in terms of energy of the emf of a battery.
  

Learning Objects §12.2

• Explain what is meant by potential difference. 
  
• State that potential difference (pd) is measured in volts. 
  
• Describe how to use a voltmeter to measure the pd across a component in a circuit. 
  
• Explain the significance in terms of energy of the emf of a battery and a pd in a circuit. 
  

Charge and Current

• Remember this one? --> 

• The Coulomb, in other words, a bag of electrons!

Charge and Current

In the previous LessonUp you learned that if charge (electrons) starts to move, we call it an Electric Current. 

You can measure the current with an Ammeter and the unit is Ampere.

I = Q / t 

[A] = [C] / [s]

Voltage / Potential Difference

In this LessonUp you will learn WHY charge moves and what it does.

Time for a video!

Watch the video about Potential Difference on the next slide.

Energy

If you want the light bulb to shine, it needs to be supplied with Energy.

You can think of the coulombs (bags of electrons) as the carriers of Energy. 

The coulombs get energy from the battery and carry it to the light bulb. They give it to the light bulb and go back to the battery to fedge more energy. 

Voltage

• Energy is measured in Joules
  
• The number of Joules that each coulomb gives to a component such as the light bulb is known as 'Volts'
• 1 V = 1 J/C
• Another word for Voltage is Potential Difference. Because we talk about the difference in Energy before and after the Coulombs gave it to a component in the circuit. 

Time for some practice:

• Read p. 164-167 (TB) 
  
• Do Summary Questions p. 164 + 166 (TB) 
  
• Do workbook exercises p. 84 + 85 (WB) 
  

Homework evaluation

In the next slide, write down the homework exercises that you found most difficult. Next lesson we will take some time to answer a few of those quetions. 

Write down the number and page of the homework exercises that you found most difficult: