Refraction & Lenses
📋 What it is
Light bends when it passes into a new material; lenses use this bending to focus or spread light.
🗣️ Coach says
When light crosses from one material to another (air to water, air to glass) it changes speed and BENDS — that’s refraction. Lenses are shaped glass that bend light on purpose: a convex lens bends rays together to a focus (magnifying), a concave lens spreads them apart.
🧠 Memory hook
New material → light bends (refraction). Convex focuses in · concave spreads out.
😂 Giggle
What did one color of the spectrum say to the other?
"We make a brilliant team when we're not being so divided!"
😲 Whoa!
A straw in a glass of water looks "broken" at the surface — that bent look is refraction, light changing speed as it enters the water.
✅ Quick check: Why does a pencil look bent where it enters a glass of water?
Say your answer out loud first — then reveal.
Light refracts (bends) as it passes between water and air, shifting where the pencil appears.
Refraction bends light at the boundary between materials.
🧪 Try it! (2 minutes)
Put a coin under an empty cup so it’s just hidden, then pour in water — refraction "lifts" it into view.