How does a mirror work?

How do we know?

↻ One of the pages with a moving picture

Glassmakers on Murano guarded their mirror secrets.

1. Light bounces off things. This is called reflection.
2. A smooth, shiny surface sends the light back neatly, all in the same direction. A rough surface scatters it every which way.
3. Light leaves a mirror at the same angle it hit the mirror, like a ball bouncing off a wall.
4. Your eyes follow that light back in a straight line, so your image seems to be behind the mirror.

In the early 1500s, glassmakers on Murano, an island in Venice, Italy, made better mirrors by coating glass with mercury and tin.

The Republic of Venice forbade Murano glassmakers from moving away and sharing their secrets. Still, by the mid-1600s some had escaped to France.

The basic way of making mercury-tin mirrors stayed the same for 400 years.

Wow number

400 years How long the basic way of making mercury-tin mirrors stayed the same.

Myth or fact?

Mirrors swap your left and right. Myth. They flip front to back. A freckle on your left cheek still shows up on the left.

Rough surfaces scatter light in all directions. Fact. Smooth, shiny surfaces send it back all in one direction.

Think about it

You can see yourself in a shiny spoon but not in a sheet of paper. Both reflect light. What makes them different?

Where in the world?

Murano, Venice, Italy where, in the early 1500s, glassmakers made better mirrors by coating glass with mercury and tin — 45.458° N, 12.3531° E.

Where these facts come from

Every number on page 99, and who measured it

Has this changed?

How a mirror works is not going to change.

Mirrors today are made differently than the mercury-tin ones from Murano, but they work on the same rule.

Words from this page

reflection

Light bouncing off a surface.

scatter

To bounce in many different directions.

mercury

A shiny silver metal that is liquid at room temperature.

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