The Law of Reflection

Lab Brief #1

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

Energy never disappears — it just hides somewhere else.

What you'll learn

Light reflects from a smooth surface with the angle of incidence equal to the angle of reflection, both measured from the normal. Rough surfaces obey the same law at every point, but their varying normals scatter the light — that is diffuse reflection.

Key words

normal
The line drawn perpendicular to a surface at the point where a ray meets it.
diffuse reflection
Scattering of light from a rough surface in many directions.

Make a hypothesis first

Before you start: which will move faster, and why?

Say your guess out loud — then find out if you were right.

Get ready

🧰 What you need

ray box or laser pointer
plane mirror
protractor
plain paper

⚠️ Safety first

Never look directly into a laser or aim it at a person or a mirror at eye level.

Step 1 of 4 · Read

Think about what you just learned: say what "normal" and "diffuse reflection" mean in your own words before you start.

Step 2 of 4 · Do

Shine a ray box at a plane mirror on paper. Mark the incident and reflected rays and the normal, and measure both angles for five different incidences. Tabulate them and state your conclusion.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 2

Angles in the law of reflection are measured from the:

How sure are you?😐 maybe

Question 2 of 2

A matt wall looks equally bright from all directions because of:

How sure are you?😐 maybe

Mind = blown

🎢 You feel weightless on a roller coaster because you and the seat are falling at the same speed.

Nice work!

You got 0 of 2 right.

Next: Refraction and Refractive Index All lessons

🎯

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✨ More to explore

🌍 Where you see this in real life: This is why airplanes can fly and why rockets reach space.

🏆 Stretch challenge (try it this week): This week, find one thing in your house that turns one kind of energy into another.

👨‍👩‍👧 For the dinner table: “Show me something at home that uses this kind of energy.”

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