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The World of Metals and Non-metals

Shine, and the sound it makes

Tap a bell. Tap a wooden bench. Which one keeps ringing?

A clean steel spoon under a light. A bell, not yet struck.
Step 1 of 3
  1. A clean steel spoon under a light. A bell, not yet struck.
  2. Light bounces off the spoon. This is lustre.
  3. The bell is struck. It rings on. This is sonorous.

The bell keeps ringing after a tap. The bench does not.

Two tests, two words

  • Lustre — a clean surface bounces light back.
  • Sonorous — struck once, it rings on for a while.

The rule

Shine and ringing are two tests. One pass is not enough.

Most metals pass both tests. Most non-metals pass neither. A wooden bench gives a dull thud, with no ringing.

Watch out!

A glass marble shines too, and it is not a metal. A magnet does not tell metal from non-metal either. Copper is a metal, yet a magnet does not pull it.

Now try it. Pick a thing. Shine it, then tap it. Is it a metal?

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This track

  1. 0 Start here
  2. 1 Shine, and the sound it makes
  3. 2 Beaten flat, or pulled into a wire
  4. 3 Carrying warmth, and carrying the loop
  5. 4 Non-metals are all around you
  6. 5 Why iron goes orange
  7. 6 The job decides which test matters
  8. 7 Checkpoint: properties, rusting and choosing
  9. 8 What burning makes: oxides
  10. 9 Why sodium sits in kerosene
  11. 10 Why gold and silver make jewellery
  12. 11 Jobs that non-metals do
  13. 12 The big picture
  14. 13 Track quiz

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