🌈 Rainbow Mind Map: Physical Quantities & Measurement

Rainbow Mind Map

Physical Quantities and Measurement

Physical Quantities and Measurement

Measurement of Volume (3D Concept)

• Definition of volume
• Units of measurement (m³, cm³, L)
• Methods for regular solids
• Displacement method for irregular solids

Volume is the quantity of three-dimensional space enclosed by a closed surface.

Volume of cube = side × side × side

Volume of cylinder = π × radius² × height

For irregular objects, water displacement method is used:

Volume = Final water level - Initial water level

Measurement of Area

• Definition of area
• Units of measurement (m², cm²)
• Regular shapes formulas
• Counting squares method

Area is the quantity that expresses the extent of a two-dimensional figure.

Area of rectangle = length × width

Area of triangle = ½ × base × height

Area of circle = π × radius²

For irregular shapes, the counting squares method can be used by overlaying a grid.

Measurement of Density

• Definition of density
• Formula and units (kg/m³, g/cm³)
• Regular solids method
• Applications in real life

Density is a measurement that compares the amount of matter an object has to its volume.

Density = Mass / Volume

To measure density of a regular solid:

1. Measure mass using a balance
2. Calculate volume using appropriate formula
3. Divide mass by volume

Density determines whether objects float or sink in fluids.

Calculation of Speed

• Definition of speed
• Units of measurement (m/s, km/h)
• Average vs instantaneous speed
• Practical measurement methods

Speed is a measure of how fast an object is moving.

Speed = Distance / Time

To measure speed:

1. Measure the distance traveled (in meters)
2. Measure the time taken (in seconds)
3. Divide distance by time

Speed is a scalar quantity (has magnitude but no direction).

Measurement of Mass

• Definition of mass
• Units (kg, g, mg)
• Instruments (beam balance, electronic balance)
• Difference between mass and weight

Mass is the amount of matter in an object. It is constant and does not change with location.

1 kg = 1000 g

Common instruments include:

• Beam Balance (for comparison)
• Electronic Balance (for quick digital measurement)

Mass differs from weight, which depends on gravity.

Measurement of Time

• Definition and importance of time
• Units (seconds, minutes, hours)
• Instruments (stopwatch, clock)
• Accurate time measurement techniques

Time is a fundamental quantity that helps us sequence events and compare durations.

1 hour = 60 minutes = 3600 seconds

Measurement tools include:

• Stopwatch (used in experiments)
• Atomic clock (high precision)

Time accuracy is critical in physics, especially in motion and oscillation studies.

Measurement of Temperature

• Definition of temperature
• Units (°C, °F, K)
• Thermometers (clinical, laboratory)
• Fixed points: Ice and steam points

Temperature indicates how hot or cold an object is, related to the average kinetic energy of particles.

°C = (°F - 32) × 5/9

Thermometers types:

• Clinical Thermometer (for body temp)
• Laboratory Thermometer (for experiments)

Standard fixed points:

Ice point = 0°C, Steam point = 100°C

Rainbow Mind Map | Physical Quantities and Measurement | © The Physics Next, 2025