Year 9 - Science
Pressure at different depths and heights
Hidden forces
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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 forces, deformation, Hooke's Law, moments, and work done. It covers pressure in liquids, atmospheric pressure, upthrust, and equilibrium, as well as simple machines and force-extension relationships, highlighting how forces affect motion, friction, and object deformation.
Lesson Summary
You will learn to describe how the pressure changes at different depths underwater and heights in the atmosphere.
Key Notes
- The bigger the surface area of a boat's hull, the bigger the upthrust on it can be.
- Pressure in liquid increases with depth because there is more liquid pushing down.
- Pressure in the atmosphere reduces with height because there is less air pushing down.
Vocabulary To Learn
- upthrust: A force acting upwards due to pressure is an upthrust.
- pressure: The pressure on a surface is the effect of a force acting over an area.
- depth: Depth is the distance under the surface of a liquid.
- atmospheric pressure: Atmospheric pressure is the pressure caused by the atmosphere, this decreases with height.
Common Mistakes To Avoid
- Pressure is greater at the bottom of a wider container than at the bottom of a narrower one.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
The bigger the surface area of a boat's hull, the bigger the upthrust on it can be. Pressure in liquid increases with depth because there is more liquid pushing down.
2. Define this scientific word and use it in context. 'upthrust'
A force acting upwards due to pressure is an upthrust. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pressure is greater at the bottom of a wider container than at the bottom of a narrower one. Correction: Discuss how the force of water in the wider container is acting over a bigger area and refer to pressure = force ÷ area.
More Lessons In This Unit
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