time is measured using a range of units and systems. some time units are based on natural events such as the time it takes for the earth to circle the sun. thesecond is the basic unit for time in the metric system.

daily time is measured using the 12 hour clock (am and pm) or the 24 hour clock.

time zones around the world allow for the effect of the rotation of the earth and the time the sun "rises"

daylight saving is an adjustment made to clocks to allow for more daylight in the evenings in summer.

key skills
  • change between different time units
  • calculate the number of hours, minutes or seconds between two times
  • change between 12 hour clock times and 24 hour clock times
  • calculate times in different time zones


24 hour clock.