Video Lesson

Lesson Objective

Dear Learners,

At the end of this section, you should be able to:

• convert one unit of length to another unit of length.
• convert one unit of mass to an other unit of mass.
• convert one unit of time to another unit of time.

Brainstorming Question

How many meters, centimetres and millimetres are there in one kilometre? How many grams are there in one kilogram? How many seconds are there in one day?

Key terms and concepts

Unit conversion

Unit conversion is the process of converting a measurement from one unit to another. This is crucial in science and everyday life to ensure consistency and accuracy in measurements. Here is a brief overview of unit conversions for length, mass, and time:

Length

• Common Units: Meter (m), Kilometre (km), Centimetre (cm), Millimetre (mm), Inch (in), Foot (ft),and Mile (mi)

Conversion Factors:

• 1 km = 1,000 m
• 1 m = 100 cm
• 1 cm = 10 mm
• 1 in = 2.54 cm
• 1 ft = 12 in
• 1 mi = 1,609.34 m

• Example Conversion:
  • Convert 5 kilometres to meters:
    • 5 km × 1,000 m/km = 5,000 m

Mass

• Common Units: Kilogram (kg), Gram (g), Milligram (mg), Ton (t), Pound (lb), and quintal.

Conversion Factors:

• 1 kg = 1,000 g
• 1 g = 1,000 mg
• 100kg = 1 quintal
• 1 t = 1,000 kg
• 1 lb = 0.453592 kg

• Example Conversion:
  • Convert 3 kilograms to grams:
    • 3 kg × 1,000 g/kg = 3,000 g

Time

• Common Units: Second (s), Minute (min), Hour (h), Day (d) and year.

Conversion Factors:

• 1 min = 60 s
• 1 h = 60 min
• 1 d = 24 h
• 1 year =365.25 days

• Example Conversion:
  • Convert 2 hours to seconds:
    • 2 h × 60 min/h × 60 s/min = 7,200 s