Cambridge IGCSE Physics Notes 1.3: Mass and Weight
Cambridge IGCSE Physics notes on mass, weight, gravitational field strength, balances, and the difference between matter and force.
Q: What does Cambridge IGCSE Physics Notes 1.3: Mass and Weight cover?
A: It follows official Cambridge Physics section 1.3 for syllabuses 0625 and 0972, with Core ideas separated from Supplement depth.
Mass describes the quantity of matter, while weight is the gravitational force acting on that mass in a gravitational field.
The ideas that organise this section
- Mass is measured in kilograms and does not depend on local gravitational field strength.
- Weight is a force measured in newtons and changes when gravitational field strength changes.
- A balance compares masses, while a force meter measures force.
Core route
Core candidates should be ready to describe, calculate, interpret, and apply the following:
- Distinguish mass and weight by meaning, unit, and measuring instrument.
- Use gravitational field strength as force per unit mass.
- Compare weights and masses using appropriate apparatus.
Supplement route
Extended candidates study all Core content and add the following depth:
- Describe weight as the effect of a gravitational field on mass.
- Apply the relationship consistently when either mass, weight, or field strength changes.
Formula route
- Relationship: weight = mass x gravitational field strength.
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 Mass and Weight, 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.
