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Lesson 7 of 10

Three strands, one method

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6 min

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A pressure cooker whistles. Which science is that?

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One everyday object: a pressure cooker.
Step 1 of 4
  1. One everyday object: a pressure cooker.
  2. Physics: steam builds up pressure.
  3. Chemistry: the food changes as it cooks.
  4. Biology: cooking kills many germs.

The idea

A pressure cooker uses physics, chemistry and biology. These are three strands, or branches, of science.

All three use one method. They ask a testable question, measure, and compare.

Earth science is another branch.

People made these divisions to organise what we know. Nature does not have such divisions.

Most real problems need several branches together. Climate change is one. Making a medicine is another. Building clean technology is a third.

Science also works with maths, technology, the arts and the social sciences. Each way of knowing helps the others.

People make science. It grows from curiosity, care and sharing. Many people, in many places and times, built it.

You may not study more science. Scientific thinking still helps. It helps you judge what you read and use tools well.

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