Measures, time and graphs
Same perimeter, different area
If the fence stays the same length, can the field get bigger?
Watch first
Measuring round the edge, covering the inside, then reading the clock.
Read the film in words (English) ↓
What the film shows
- A finger traces the edge of a rectangle while the perimeter total counts up.
- The same rectangle fills with unit squares to show its area.
- Units convert on screen: centimetres to metres, grams to kilograms, millilitres to litres.
- A 12-hour clock and a 24-hour clock show the same moment side by side, then a bar chart is read off.
- The perimeter and unit-swap practicals for this unit repeat all of this with a tape measure.
What you need
Tick each one as you find it — 0 of 5 ready.
Stay safe: Take care with scissors when you cut the string, and cut on a board.
Plan the fair test
- Change: The shape of the rectangle
- Measure: The area inside it
- Keep the same: The same 36 cm loop of string, the same squared paper
Objectives this evidences
- Find the area of rectilinear shapes by counting squares
- Measure and calculate the perimeter of a rectilinear figure, including squares, in centimetres and metres
Do it, one step at a time
Step 1 of 5
- Step 1. Lay the string loop on the squared paper as a rectangle 1 cm by 17 cm. Draw round it.
- Step 2. Count the squares inside to find the area, and check the perimeter is still 36 cm.
- Step 3. Reshape the same loop into 2 × 16, then 4 × 14, then 8 × 10, then 9 × 9, drawing and counting each one.
- Step 4. Put every result into a table with three columns: sides, perimeter, area.
- Step 5. Look for the pattern, then predict which shape gives the biggest area before you draw it.
What should happen
Every rectangle has a perimeter of 36 cm, but the area grows as the sides get closer in length — the square is biggest.
Think about: A farmer with 36 m of fencing wants the most grass. What shape should the field be, and why?
Write up your result
A sentence or two is enough to save it.
The lessons behind this practical
Each one opens with the same short film, and the film has a written transcript underneath if reading is easier than watching.
Now the quiz for this topic
Questions come from the lessons behind this practical, so nothing is asked that has not been taught.
Quiz
Measures, time and graphs quiz
14 questions from the lessons in this stage. No timer, and you can try again as many times as you like.