You can indirectly compare the duration of events by using a sand timer or a candle timer. At this stage time telling time skills will focus on hour and half-hour. Duration Measuring the duration of events using non-standard or informal units is the third stage in the learning sequence. Beginning with non-standard but familiar units allows the children to focus on the process of repeatedly using a unit as a measuring device. Parts of the body provide interesting units for introductory use.
Children can compare and order events using heartbeats, hand clapping and hopping.
Children can also make their own timing devises and calibrate these arbitrarily, for example, by making marks at regular intervals on a burning candle, or by letting sand run through a small hole into a calibrated container. From the earliest of these experiences, children should be encouraged to estimate. Initially these estimations may be no more than guesses, but estimating involves the children in developing a sense of the size of the time unit. As everyday life involves estimating at least as frequently as finding exact measures, the skill of estimating is important. Although non-standard units reinforce most of the basic measuring principles, children need to realise that they are limited as a means of communication.