General Science Grade 8 Measurement

Measurement Overview

• Measurement determines the magnitude of a quantity against an agreed standard.
• Indigenous and modern methods exist for measurement practices.

Indigenous Methods of Measurement

• Practices have been localized and passed through generations.
• Focuses on measuring length, mass, and time.

Length Measurement

• Length measures the distance between two points.
• Indigenous units of length in Ethiopia include:
  • Hand-span: Distance from the tip of the little finger to the thumb tip.
  • Digit: Width of an adult fingertip.
  • Cubit: Distance from elbow tip to middle finger tip when extended.
  • Foot: Distance from heel to big toe tip.
  • Pace: Distance of one normal walking step.
  • Arm Span: Distance from fingertip of one hand to the other when arms are stretched.

Mass Measurement

• Local mass measurement tools include:
  • Quntal: Equivalent to 100 kilograms, used for grains.
  • Feresula: Measures pepper and coffee, equivalent to 17 kilograms.

Time Measurement

• Time is the measure of an interval's duration.
• Indigenous method uses the shadow of a tree to tell time based on the Sun's position.
• Historical time measuring devices:
  • Sundial, Sand Clock, and Water Clock.

Volume Measurement

• Volume measures the space an object occupies.
• Common tools in Addis Ababa markets for measuring volume:
  • Jog: Plastic cup for liquids.
  • Tassa: Can for cereals and liquids.
  • Sini: Ceramic cup for coffee and spices.
  • Birchiko: Glass for measuring various items.

SI Units and Conversions

• Length: SI unit is meter (m).
  • Conversions:
    • 1 km = 1000 m
    • 1 m = 100 cm
    • 1 cm = 10 mm
• Time: SI unit is second (s).
  • Time conversions:
    • 1 hour = 60 minutes = 3600 seconds
    • 1 day = 24 hours
    • 1 week = 7 days
    • 1 year = 365 or 366 days

Temperature Measurement

• Devices used: Thermometers (analog or digital).
• SI unit of temperature is Kelvin; other units include °C and °F.