Measure the classroom

Learning intention: 

CL3 Find areas of rectangles by applying multiplication

CL4 Use side lengths to find the perimeters and areas

CL5 Find the perimeters and areas of composite shapes

Task

How much will it cost to improve the classroom with new skirting board, paint, carpet and a new heatpump?

1. In your exercise books, create a sketch of the plan view (top view) of the classroom. Label each wall (1,  2, 3 etc)

2. Measure the dimensions (length and height) of each wall and add that to a sketch in your book (CL3 use rectangles only, CL5 use composite shapes)

3. Calculate the perimeter of the classroom (for the skirting board) in metres and write this on the plan view. It costs $30 for a 6m length. How many lengths will we need and how much will it cost?

4. Calculate the area of each wall in metres squared and write this in the middle of the sketch.

5. Measure the dimensions of any windows or whiteboards. Draw these onto your sketch, calculate the area and subtract from the area of the wall. 

6. Add up the total area of all the walls less the area of windows and whiteboards.

Now you may use your device and a Google sheet (click this link to make a copy) to help with your calculations.

7. Calculate the amount of paint needed  in litres (the rate for paint is it covers 11m2/L of paint)

8. Calculate the cost for the paint required (see this link for the cost of paint per litre)

9. Factor in having two coats of paint.

10. Calculate the volume of the room. Use this measurement to determine the size of a heat pump big enough to heat the room.

Extension

Make a scale model of the class using carboard. You could think about using a Net. You can prepare a drawing that can be cut out using the Laser Cutter

Resources

Measure Up - Smart phone measuring app

Calculating heat pump size: here’s a basic calculation from consumer.org.nz you can try for CL5.

Step 1 – Calculate the room’s volume in cubic meters.

Step 2 – Multiply that by 44 watts.

Step 2 - Add 10% to large window areas and a further 10-20% for partial or no insulation.

Step 3 - Multiply this figure by 1.5 for living areas, 1.2 for a bedroom, and 0.8 for other areas.

Example: A partially insulated lounge, 4m x 5m x 2.4m high + 10% for lack of insulation = 53 cubic metres room volume (rounded up). Multiply by 44watts = 2332, now by 1.5 because it’s a lounge = 3498 watts. This means you will need a 3.5kW heat pump.