circulation system

• Indigenous methods of measurement

  • Hand-span
  • Digit
  • Cubit
  • Foot
  • Pace
  • Arm span
• Hand-span


  • Measure from the tip of your little finger to the tip of your thumb when your hand is stretched out
• Digit


  • Width of an adult human male fingertip
• Cubit


  • Measure of distance from the tip of one's elbow to the tip of the middle finger when your arm is extended
• Foot


  • Measure of distance from the back of the heel to the tip of the big toe
• Pace


  • Linear distance measure of a person's extended walk, distance measured from the heel of one foot to the heel of the same foot when it next touched the ground
• Arm span


  • Distance from the middle fingertip of the left hand to that of the right hand when you stretch your arms out as far as they can reach
• The amount of matter present in a substance is called mass
• Indigenous units of mass measurement

  • Weqet
  • Quntal
  • Feresula
• Weqet


  • Mass measuring unit usually used to measure the mass of powder of gold in local markets
• Quntal


  • Bag used to measure the mass of grains, equal to a hundred kilogram
• Feresula


  • Used to measure the mass of pepper and coffee, equal to 17 kilogram
• Time is the measure of the duration for an interval
• Indigenous method of measuring time

  • Using the shadow of a tree to tell the approximate time of the day
• Indigenous volume measuring devices

  • Jog
  • Tassa
  • Sini
  • Birchiko
  • Kubaya
• Jog

  • Plastic cup used for measuring the volume of liquids
• Tassa


  • Can used to measure cereals, pulses, liquids and solids
• Sini


  • Small ceramic cup often used for measuring coffee, pulses and spices
• Birchiko


  • Glass often for measuring pulses and liquids
• Kubaya


  • Mug, often used for measuring cereals, pulses and liquids
• Volume


  The measure of the space occupied by an object
• Indigenous volume measurement tools used in Addis Ababa markets

  • Jog: A plastic cup used for measuring the volume of liquids
  • Tassa: A can used to measure cereals, pulses, liquids and solids
  • Sini: A small ceramic cup often used for measuring coffee, pulses and spices
  • Birchiko: A glass often for measuring pulses and liquids
  • Kubaya: A mug, often used for measuring cereals, pulses and liquids
• Physical quantity


  A property of an object that can be measured or calculated from other physical quantity
• Examples of physical quantities

  • Length
  • Mass
  • Time
  • Temperature
  • Area
  • Volume
  • Density
  • Force
• Fundamental quantities


  Quantities which cannot be expressed in terms of any other quantity
• Fundamental physical quantities


  • Length
  • Mass
  • Time
  • Temperature
  • Electric current
  • Luminous intensity
  • Amount of a substance
• The International System of Units (SI) is currently used all over the world
• Measurement


  The comparison of an unknown quantity with some known quantity
• Unit


  The known fixed quantity used as the standard for measurement
• Fundamental units


  The units used to measure fundamental quantities
• Derived quantities


  Physical quantities which depend on one or more fundamental quantities for their measurements
• Derived units


  The units used to measure derived quantities, depend on fundamental units
• Derived quantities and their SI units

  • Area: m2
  • Volume: m3
  • Speed: m/s
  • Density: kg/m3
• Prefix


  A shorthand form of writing very large and very small numbers
• Examples of SI prefixes

  • Mega (M): million
  • Kilo (k): thousand
  • Centi (c): hundredth
  • Milli (m): thousandth
• Converting between units


  Move the decimal point to multiply/divide by the value of the prefix
• Balance


  Instrument used to measure mass, works on the principle that the amount of extension/compression of a spring is proportional to the mass
• Units of mass


  • Kilogram (kg)
  • Gram (g)
  • Milligram (mg)
  • Quintal
  • Tonne
• Length


  Measure of how long an object is
• Units of length


  • Meter (m)
  • Kilometer (km)
  • Centimeter (cm)
  • Millimeter (mm)