1. How an engine works
This PowerPoint presentation has been downloaded from Presentation written by John Clegg.
© Copyright Springer Nature Ltd Animation licensed by The Science Museum.

2. First … Do exercise 1 on the worksheet: label the diagram.
2. Do exercise 2 on the worksheet: match the pictures with the correct caption.

3. Next
Look at the following picture slides and check your answers.

4. A running petrol engine works like this …

5. Suck! As the piston moves down the intake valve opens and air mixed with a tiny drop of petrol, is pumped into the chamber.

6. Squeeze! As the piston moves up both valves are closed and the petrol/air mix gets squashed.

7. Bang! The spark plug sparks, causing the squashed petrol/air mix in the chamber to explode and push the piston down and up.

8. Blow! As the piston moves up, the exhaust valve opens and the exhaust gasses get pushed out of the car via the exhaust pipe.

9. As the piston moves down and up it pushes the crankshaft round.

10. This makes the car’s wheels go round.

11. Now …
4. Do exercise 3 on the worksheet: join the phrases to show the correct sequence of actions.

12. Presentation (for classes working in groups only)
5. Give an oral commentary on the picture slides.