# How long is a kilometre?

### The Basic Idea

Most children have little concept of time or length as there are too abstract, large or unfamiliar to them. Estimation is a key element of this activity. Helping children to work from micro measurement which they are familiar with to working up to large numbers they are less familiar with matching this to time. Often people use time to measure distance, not necessarily distance itself, i.e. people say how long it takes 20 mins to walk from A to B, not that it is 2.5 kms.

In a natural environment place a cone as a strategic point. Ask children to estimate and mark out 1 m – place a cone. Measure it, and adjust. Estimate 10m, then 50m, then 100m; discuss what they are doing to make their estimations. Emphasise the importance of counting in 10s,and the importance of the base of 10.

Go back to the start and using trundle wheels to measure the distances accurately. One child can count the 1s, another to count the tens, i.e. 1 ten, 2 tens, 3 tens…; and another to total the 10s, i.e. 10, 20, 30, 40, 50…

From the 100m cone, time how long it takes to walk back to beginning and repeat so you end up at the 100 m point again; average the two times.

So… therefore if it takes ‘x’ amount of time to walk 100m… how long would it take to walk tens times that = 1000m?

If you have time, walk 1000m and test the time estimates…

### How to take it even further or make it more challenging

Using the time calculation, back in the classroom choose location within a few kms and ask the children to work out how long it would to walk there. What about a nearby town? City? London? Paris? Moscow?

This is also a good opportunity for some early algebra perhaps? Ask your Maths Lead for help (there is not enough room here to explain!).