Measurement Basic Science J S 3 | First Term Scheme | Week 6
Topic: Measurement
Week 6
Basic Science J S 3
Objectives:
Measurement Basic Science J S 3 | First Term Scheme | Week 6
By the end of the lesson, students should be able to:
- Differentiate between fundamental and derived quantities.
- Understand the difference between scalar and vector quantities.
- Identify the meaning, units, and instruments used to measure various physical quantities like time, mass, distance, volume, temperature, density, force, and pressure.
Lesson Outline:
1. Fundamental and Derived Quantities
- Definition:
- Fundamental Quantities: Physical quantities that cannot be derived from any other quantity. They are the basic units of measurement in physics.
- Derived Quantities: These are quantities derived from the combination of fundamental quantities.
- Examples of Fundamental Quantities and their Units:
- Length – Meter (m)
- Mass – Kilogram (kg)
- Time – Second (s)
- Electric current – Ampere (A)
- Temperature – Kelvin (K)
- Amount of substance – Mole (mol)
- Luminous intensity – Candela (cd)
- Examples of Derived Quantities and their Units:
- Area (m²)
- Volume (m³)
- Speed (m/s)
- Force (Newton, N)
- Pressure (Pascal, Pa)
- Density (kg/m³)
2. Scalar and Vector Quantities
- Definition:
- Scalar Quantities: These are quantities that have only magnitude (size) without direction. Examples include mass, time, distance, speed, temperature, energy.
- Vector Quantities: These are quantities that have both magnitude and direction. Examples include displacement, velocity, acceleration, force, weight.
- Comparison:
- Scalar Quantities are described only by their numerical value (e.g., 10 kg, 5 seconds).
- Vector Quantities require both a numerical value and a direction (e.g., 10 N to the east, 5 m/s north).
3. Meaning, Units, and Instruments for Measuring Physical Quantities
| Physical Quantity | Meaning | Unit | Instrument |
|---|---|---|---|
| Time | Duration of an event or the interval between two events. | Seconds (s) | Stopwatch, Clock |
| Mass | The amount of matter in an object. | Kilogram (kg) | Balance (beam or electronic) |
| Distance | The length of the path traveled by an object. | Meter (m) | Meter ruler, Measuring tape |
| Volume | The amount of space occupied by an object. | Cubic meter (m³), Liter (L) | Measuring cylinder, Burette, Pipette |
| Temperature | The degree of hotness or coldness of an object. | Kelvin (K), Celsius (°C) | Thermometer |
| Density | The mass per unit volume of a substance. | Kilogram per cubic meter (kg/m³) | Derived from mass and volume measurements (Mass ÷ Volume) |
| Force | A push or pull on an object. | Newton (N) | Spring balance, Force meter |
| Pressure | Force applied per unit area. | Pascal (Pa) | Barometer, Manometer |
4. Conclusion:
- Measurement is essential in the study of science. Fundamental quantities provide the basic units, while derived quantities help in understanding more complex phenomena. Scalar and vector quantities distinguish between values with and without direction, and precise instruments are used to measure different physical properties.
5. Assessment/Practice:
- Have students practice identifying and classifying quantities as either fundamental/derived and scalar/vector.
- Ask students to convert units of various physical quantities (e.g., grams to kilograms, minutes to seconds).
