# Efficiency

This lesson summarises many of the foundational concepts about energy that have been introduced in lessons 1, 2 and 3 by investigating pendulums. It then discusses useful and wasted energy transfers and calculates efficiency from written questions and Sankey diagrams.

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, letâ€™s see what you can remember from this topic. Hereâ€™s a quick quiz!

Q1.Which part of the Bunsen burner do you twist to open or close the air hole?

1/10

Q2.Which of these is the name we give to the hotter flame on a Bunsen burner?

2/10

Q3.Which is the variable that we change?

3/10

Q4.Which is the variable that we observe?

4/10

Q5.Which is the variable that we keep the same?

5/10

Q6.Calculate the average (mean) of these numbers: 6, 5, 7, 9, 8

6/10

Q7.What type of word should every step of a method start with?

7/10

Q8.Which energy store is full when you stand on top of a hill?

8/10

Q9.Which energy store is fills up as you run down a hill?

9/10

Q10.What is 33 J in kJ?

10/10

Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, letâ€™s see what you can remember from this topic. Hereâ€™s a quick quiz!

Q1.Which part of the Bunsen burner do you twist to open or close the air hole?

1/10

Q2.Which of these is the name we give to the hotter flame on a Bunsen burner?

2/10

Q3.Which is the variable that we change?

3/10

Q4.Which is the variable that we observe?

4/10

Q5.Which is the variable that we keep the same?

5/10

Q6.Calculate the average (mean) of these numbers: 6, 5, 7, 9, 8

6/10

Q7.What type of word should every step of a method start with?

7/10

Q8.Which energy store is full when you stand on top of a hill?

8/10

Q9.Which energy store is fills up as you run down a hill?

9/10

Q10.What is 33 J in kJ?

10/10

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the â€˜Resume Videoâ€™ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click â€˜Nextâ€™ below.

Quiz:

# Efficiency

This quiz will have questions from the lesson called 'Efficiency' and previous lessons in the Energy topic. Please complete this quiz to consolidate your learning.

Q1.If the total supplied energy to the fan is 250 J and 200 J is usefully transferred to the kinetic store, how much is wasted by heating?

1/10

Q2.If the total supplied energy to the fan is 250 J and 200 J is usefully transferred to the kinetic store, how efficient is the fan?

2/10

Q3.Which energy pathway is used to transfer energy from a battery to the motor in the fan (which makes the blades spin round)?

3/10

Q4.Which is the main useful energy store that fills, when an oven is turned on?

4/10

Q5.This Sankey diagram is for an oven. Assuming each little box is 1 J, how much energy is transferred usefully?

5/10

Q6.This Sankey diagram is for an oven. Assuming each little box is 1 J, what is the efficiency of the microwave?

6/10

Q7.When an oven is turned on, most of the total energy supplied is usefully transferred to the food to cook it, but where does the wasted energy go?

7/10

Q8.Which of these is the name we give to the cooler flame on a Bunsen burner?

8/10

Q9.What is 20 kJ in J?

9/10

Q10.Calculate the average (mean) of these numbers: 12, 15, 9, 21, 18

10/10

Quiz:

# Efficiency

This quiz will have questions from the lesson called 'Efficiency' and previous lessons in the Energy topic. Please complete this quiz to consolidate your learning.

Q1.If the total supplied energy to the fan is 250 J and 200 J is usefully transferred to the kinetic store, how much is wasted by heating?

1/10

Q2.If the total supplied energy to the fan is 250 J and 200 J is usefully transferred to the kinetic store, how efficient is the fan?

2/10

Q3.Which energy pathway is used to transfer energy from a battery to the motor in the fan (which makes the blades spin round)?

3/10

Q4.Which is the main useful energy store that fills, when an oven is turned on?

4/10

Q5.This Sankey diagram is for an oven. Assuming each little box is 1 J, how much energy is transferred usefully?

5/10

Q6.This Sankey diagram is for an oven. Assuming each little box is 1 J, what is the efficiency of the microwave?

6/10

Q7.When an oven is turned on, most of the total energy supplied is usefully transferred to the food to cook it, but where does the wasted energy go?

7/10

Q8.Which of these is the name we give to the cooler flame on a Bunsen burner?

8/10

Q9.What is 20 kJ in J?

9/10

Q10.Calculate the average (mean) of these numbers: 12, 15, 9, 21, 18

10/10

# Lesson summary: Efficiency

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Walk

On the spot:
Dance