Cambridge IGCSE Physics Notes 1.8: Pressure
Cambridge IGCSE Physics pressure notes on force per area, liquid pressure, atmospheric pressure, depth, density, and pressure differences.
Q: What does Cambridge IGCSE Physics Notes 1.8: Pressure cover?
A: It follows official Cambridge Physics section 1.8 for syllabuses 0625 and 0972, with Core ideas separated from Supplement depth.
Pressure describes how concentrated a force is over area, while liquid pressure increases with depth and liquid density.
The ideas that organise this section
- For the same force, a smaller contact area produces greater pressure.
- At the same depth, a denser liquid produces greater pressure.
- A pressure difference can produce a resultant force and fluid movement.
Core route
Core candidates should be ready to describe, calculate, interpret, and apply the following:
- Calculate pressure from normal force and area.
- Describe qualitatively how liquid pressure varies with depth and density.
- Explain familiar effects of atmospheric pressure.
Supplement route
Extended candidates study all Core content and add the following depth:
- Calculate the pressure due to a liquid column.
- Apply pressure differences to manometers, barometers, or related contexts when data are supplied.
Formula route
- Relationship: pressure = force / area.
- Relationship: liquid pressure = density x gravitational field strength x depth.
Write the relationship before substituting. Convert units first, keep extra figures during working, and round only the final answer to sensible precision.
Build a connected model
In Pressure, a strong answer connects the named quantity or model to observable evidence. Begin by defining the physical quantity in words or with its relationship. Identify which values are scalars and which require a direction. Represent the situation with a labelled diagram, graph, field pattern, ray or circuit when that makes the relationship visible. The representation is part of the reasoning: its labels, arrows and scale should agree with the written explanation.
For a calculation, write the governing relationship before substitution, convert prefixes and time units, keep unrounded values during working and attach the correct final unit. For a qualitative question, use a cause-link-consequence chain. Name what changes, state the physical mechanism that links the change to the system, and then give the measurable result. If two cases are compared, hold unrelated variables constant and use the same physical principle for both.
