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Home / SCSA / Year 6 - Science / Lesson 6 — Irreversible Changes and New Substances / Four signs a new substance has formed

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Four signs a new substance has formed

How do we know a brand-new substance has formed? Scientists look for four telltale signs.

1. A gas is produced

Bubbling or fizzing when no heat is boiling it.

2. A colour change

A new colour that won't wash back out.

3. Heat or light is given off

The mixture warms up, cools down, or glows.

4. A new material appears

Like ash, rust, or a solid forming in a liquid.

You usually only need to spot one of these to suspect a chemical change is happening.

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