# KS3 Maths – Keeping the Roads Open

## Outline

The main activity is essentially a simulation of County Council decision making when roads are forecast to freeze. Pupils use temperature forecasts from the Met Office to decide how much salt to spread on the roads and calculate the cost.

## Objectives

By the end of the lesson:

• All student will use the information from a graph and translate into a response using a key.
• Most students will evaluate the decisions made in light of additional information.

## Starter

Discuss the effects of icy roads, videos of cars skidding from YouTube can be used to illustrate the point.

What are the impacts? Tease out responses of the costs in terms of financial, for example: social costs (costs to NHS/Police), economic costs (lost productivity of workers having time off) and personal costs (damage of car). Make the point that with costs like these it is worth gritting to reduce the impacts.

## Main Body

Pupils (working in pairs) to be given the road gritting planning sheet.

Pupils should use the gritting flowchart (based on a real life plan used by the councils) to decide how much grit should be spread by the council each night following the forecasts given. Pupils should be reminded that weather forecasts are forecasts of what is expected to happen and that conditions might change meaning reality is a little different.

Give the pupils the forecast information sheet.

Go through the first example showing forecast temperature, allowing students to decide what quantity of grit to use and then actual temperature, review this decision.

Using the forecasts for the next few days allow students to assess each day and work out the cost of grit for the week.

Once pupils have successfully assessed the cost of their choice for each day the actual temperature graph for that day can be revealed.

## Plenary

Discuss the difference in choices, and the impact that pupils felt they made by their choices.