Year 8 - Science
Changing the speed of a parachute
Moving by force
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores speed, forces, and motion, including effects on objects. It covers deriving equations, calculations, and distance-time graphs. Learn to use force arrows, identify balanced and unbalanced forces, and understand their impact on movement.
Lesson Summary
You will learn to clearly describe how drag forces affect the motion of falling objects.
Key Notes
- The gravitational force on a falling object is constant.
- The drag force on a falling obejct depends on its speed and shape.
- Objects falling through the air will reach a terminal velocity when the drag and gravitational forces are equal.
- The terminal velocity can be changed by changing the drag force (e.g. with a parachute).
Vocabulary To Learn
- gravitational force: The gravitational force on something pulls it downwards, towards Earth.
- drag force: When an object moves through a fluid there is a drag force that opposes the movement.
- resultant force: A resultant force is the overall effect of a set of forces on an object, taking their directions into account.
- parachute: A parachute is used to increase the size of drag forces. This slows down the object it is attached to.
- terminal velocity: An object reaches a terminal velocity when the drag and gravitational forces are equal.
Common Mistakes To Avoid
- Video of skydiving may lead pupils to think opening a parachute makes a skydiver 'shoot upwards'.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The gravitational force on a falling object is constant. The drag force on a falling obejct depends on its speed and shape.
2. Define this scientific word and use it in context. 'gravitational force'
The gravitational force on something pulls it downwards, towards Earth. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Video of skydiving may lead pupils to think opening a parachute makes a skydiver 'shoot upwards'. Correction: Explain that this 'upwards motion' is relative motion to a cameraman. Discuss what a sudden upwards motion would do to a falling skydiver.
More Lessons In This Unit
- Calculating speed Study Guide
- Changing speed Study Guide
- Comparing the speeds of different parachutes Study Guide
- Interpreting distance-time graphs Study Guide
- Measuring speed accurately Study Guide
- Measuring speed: practical Study Guide
- Newton's First Law Study Guide
- Reading distance-time graphs Study Guide
- Streamlining Study Guide
Browse all guides in the Year 8 Science guide library.