Egypt Primary 5 Science, Week 11: Builders who measure

The right material, the right tool

Week 11 · Theme 2 Matter and Energy, Unit 2 Particles in Motion, Concept 2.2 Describing and Measuring Matter (B) and Concept 2.3 Comparing Changes in Matter (A) · 3 lessons

Builders who measure

Discovery Education Science P5: Term 1, Unit 2, pp. 167–172

GoalExplain with a claim, evidence and reasoning why roofs differ, and describe how builders, bakers and mapmakers use measurements.

New words

architect · a person who designs buildings and chooses the materials for themprecise · exact, with only a very small mistakemap · a drawing of a place that gives information about it

Explanation

A roof must protect people from sun, rain and wind, so the best roof depends on the climate. In hot, dry places, thick flat roofs of concrete or mud brick slow down the heat, and flat roofs are common in Upper Egypt. Where heavy rain falls, a sloping roof of tiles lets the water run off. To explain a choice like this, scientists use three parts. The claim is a one-sentence answer, and it should not start with yes or no. The evidence is what you measured or saw. The reasoning says why the evidence supports the claim. Many jobs depend on exact measurements. A builder measures boards so that walls fit. An architect chooses strong, long-lasting materials. A baker weighs flour and measures water so that the bread turns out the same each time. A cartographer measures the land and draws maps that show roads, hills and rivers.

Part	It answers…	Example about a roof
Claim	What can you conclude?	A light-coloured roof keeps a hot house cooler.
Evidence	What did you measure or see?	Under white card 31 °C, under black card 38 °C.
Reasoning	Why does the evidence fit?	Light colours send back more sunlight, so less heat gets in.

Worked examples

Place	Roof	Useful property
hot and dry	thick, flat, light-coloured	slows heat
rainy	sloping tiles	water runs off
snowy	steep, smooth	snow slides off

The table shows three climates and the roofs that suit them. Each roof is chosen for a property: how much heat it lets through, how well it sheds water, or how well snow slides off.

Tarek’s uncle builds a shed. A board must be 120 cm long. He measures twice before he cuts, because a board that is too short cannot be mended. If he cuts it 3 cm too short, it is 120 − 3 = 117 cm long.

measure the land→draw the map→planners decide

A cartographer measures the land and draws a map. Planners use the map to decide where a school can be built, which roads are needed and which fields might flood when it rains.

Class activity

Roof test (a sunny day, hats on, a grown-up helps). Lay a white card and a black card of the same size side by side in the sunshine. A grown-up slides a thermometer under each card and reads the numbers after 15 minutes. Write your results in a table, then write a claim, evidence and reasoning. Nobody looks at the Sun.

Practice

Write a claim that answers: why do rainy places often have sloping roofs?

A board must be 150 cm long, but the builder cuts it 142 cm long. How much too short is it?

Is this sentence a claim, evidence or reasoning? “Under the white card the thermometer read 31 °C, and under the black card it read 38 °C.”

Name two jobs where people need exact measurements and say what they measure.