Testing Materials for Uses
Give reasons, based on evidence from comparative and fair tests, for the particular uses of everyday materials including metals, wood, and plastic
What a learner can do afterwards
- Design a fair test to compare a specific property of two or more materials
- Present test results as evidence for why a material is suited to a particular use
- Explain the link between a material's tested properties and its real-world application
1 · Read
Match a material's properties to its job. A rain cover needs to block water. Tests give evidence for that choice. Results describe the samples and property tested. Holding more weight before bending shows better resistance to bending in that test, not suitability for every job.
To compare water getting through in a set time, use equal-sized samples, equal water amounts and equal times. To compare how much strips bend, keep their size, thickness, support and the force the same. Ask an adult to help. Never test hot pans, sharp pieces or heavy loads yourself.
For a job that needs to hold a load without bending, choose the sample that held the greatest load. To find how much more it held, subtract the smaller result from the larger: 6 kg minus 2 kg is 4 kg.
A metal pan body carries heat to the food. Some pans have heat-resistant plastic handles because plastic carries heat more slowly than metal. A handle can still become hot. Do not touch a pan to test it. An adult should check it and use suitable protection.
A waterproof cover must block water. If it also needs to fold, test whether it bends without breaking. Choose a sample that meets both needs. A water test cannot tell you whether a sample will bend.
Fair tests give evidence, and matching that evidence to the job tells you which material to use.
The lesson, questions and study cards were written for this dataset. Numerical material-test results are illustrative examples, not published measurements.
These five readings and four study cards were written for this dataset. The readings describe imagined material comparisons.
More to read
Test a toy wrapper
A wrapper for a toy parcel needs to fold without tearing. Imagine comparing paper and plastic samples of the same length, width and thickness. Fold each around the same toy in the same way.
Write down what happens. A sample that folds without tearing may suit the parcel. That test does not tell you whether water can pass through it. Test water resistance separately before choosing a wrapper for a wet place.
Keep water out
A toy shelter needs a cover that blocks rain. With an adult, compare equal-sized samples over matching openings. Add the same small amount of cold water to each. Check underneath after the same time.
Record whether water passed through. Use those results to choose a cover. Keeping water out during this test is useful evidence. It does not show how well the cover will survive months of wind and rain.
Compare loads before choosing
Imagine an adult testing strips for a model shelf. Each strip has the same length, width and thickness, and rests on the same supports. The adult adds equal loads in the same steps and records when each strip starts bending.
The strip that holds the greatest load resists bending best in this test. Its result describes this sample, not every object made from that material. Use recorded results for this comparison. Do not carry out heavy-load tests yourself.
Compare covers for a cold bottle
Imagine comparing two covers for a cold-water bottle. Use matching bottles with equal amounts of water at the same starting temperature. Put a different cover on each bottle. Leave both in the same room for the same time.
An adult can help measure the water temperature before and after. The cover that keeps the water cooler has done better in this test. The result compares the whole covers. Their materials, thickness and design can all affect it.
Check both needs
A folding rain cover has two needs. It must block water and bend without breaking. A water test answers one question. A bending test answers the other.
Record a result for each property. A sample that blocks water but stays stiff meets only one need. Choose using both results. Ask an adult to help with tests, and use safe samples without sharp edges.
2 · Watch
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Where it sits
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.