measurement

• We will learn how to measure length, area, volume, time, temperature and mass
• We will also learn to choose suitable instruments to measure these
• We need where units of measurements
• It is important to take measurements accurately
• Metre


  Unit of length
• Lengths smaller than a metre

  • Can be measured in centimetres or millimetres
• Lengths much larger than a metre


  • Can be measured in kilometres
• Ruler or metre stick


  Most basic instrument
• Zero error - read from zero, not the end of the ruler
• Parallax error - Look straight on not from the side
• Digital callipers


  Can be used to measure small distances, especially useful for measuring the diameter of circular objects
• Odometer


  Can be used to measure the length of a curved line for a short distance like a road on a map
• Trundle wheel


  Can be used to measure the length of a long distance, for example the length of a running track
• Area


  The amount of surface enclosed within an object's lines
• Calculating area of a regular shape

  Area = length x width
• Volume


  The amount of space that an object takes up
• Calculating volume of a rectangular-shaped object

  Volume = length x width x height
• Graduated cylinder


  Used to measure the volume of a liquid
• Measuring volume of an irregular-shaped object


  Use the method of water displacement
• Time


  Can be measured using a watch, clock or an electronic device (digital timer)
• Second


  Unit of time
• Digital timer


  • Can measure time in hundredths and thousandths of a second (milliseconds)
• Resolution


  The level of accuracy of a measuring instrument
• Accuracy


  How close a measured value is to its actual value