Page 1 - Lesson Note-Physical quantity

SAI INTERNATIONAL SCHOOL
Class 6
Lesson notes
Subject- Physics

Ch. - Measurement and motion
Subtopic- Physical Quantity

Physical quantities:
Ø Any quantities that can be measured are known as physical quantities.
Ø Fundamental physical quantities:
o The physical quantities that are unique and cannot be expressed in
terms of anything else are known as fundamental physical quantities.
o E.g. mass, length, temperature and time.
Ø Derived physical quantities
o Physical quantities that can be expressed as the combination of
fundamental physical quantities are known as derived physical
quantities.
o E.g. weight, area, heat and density.

The instruments or tools used for measuring any quantity are known as measuring
tools.

Useful Examples from our day to day activities:
1. Ruler Measuring a Pencil – Shows how to measure length properly from the
zero mark.

2. Beam Balance – Demonstrates comparison of masses using standard
weights.

3. Thermometer in Water – Indicates how to measure temperature.

4. Clock or Stopwatch – Measuring time during activities.