Measurement Concepts

1. Units of Length

   • Millimetre (mm): The smallest unit, used to measure tiny objects.
   • Centimetre (cm): 1 cm = 10 mm. Used to measure small lengths, like the width of a book.
   • Metre (m): 1 m = 100 cm = 1000 mm. Used for measuring larger objects, like the height of a door.
   • Kilometre (km): 1 km = 1000 m. Used for measuring long distances, like the length of a road.

2. Units of Weight (Mass)

   • Milligram (mg): The smallest unit of weight, used for very light objects like a grain of sand.
   • Gram (g): 1 g = 1000 mg. Used for measuring small weights, like a pencil.
   • Kilogram (kg): 1 kg = 1000 g. Used for measuring heavier objects, like a bag of rice.
   • Tonne (t): 1 t = 1000 kg. Used for measuring very heavy things, like a car.

3. Units of Capacity (Volume)

   • Millilitre (ml): Used for measuring very small volumes, like medicine.
   • Litre (l): 1 l = 1000 ml. Used for measuring larger volumes, like a bottle of water.

4. Conversion between Units

   • To convert from a larger unit to a smaller unit, multiply.
     • Example: 1 m = 100 cm (so to convert 2 m to cm, you do 2 × 100 = 200 cm).
   • To convert from a smaller unit to a larger unit, divide.
     • Example: 1000 g = 1 kg (so to convert 3000 g to kg, you do 3000 ÷ 1000 = 3 kg).

5. Measurement of Temperature

   • Celsius (°C): A scale to measure temperature. Water freezes at 0°C and boils at 100°C.
   • Fahrenheit (°F): Another scale where water freezes at 32°F and boils at 212°F.
   • Conversion Formula:
     • 
       $°F = \frac{9}{5} \times °C + 32$
       
     • 
       $°C = \frac{5}{9} \times (°F – 32)$
       

6. Time Measurement

   • Seconds (s): The smallest unit of time.
   • Minutes (min): 1 min = 60 s.
   • Hours (h): 1 h = 60 min = 3600 s.
   • Days and Years: 1 day = 24 h, and 1 year = 365 days.