You've helped them one at a time. The real understanding is how the ideas CONNECT — teach that next.
Bend (refraction — light slows and bends entering a denser material) ×Spread (dispersion — different wavelengths bend by different amounts, making a spectrum)
White light enters a prism and comes out as a rainbow. How do Bend and Spread explain that?
Bend then says: “A prism creates brand-new colors out of nothing, with no connection to how it bends light.” — is that right?
The link: dispersion is refraction that bends each color by a different amount.
Bend each color differently, and white light fans out.
Mirror (reflection — an incoming ray bounces back off a surface) ×Focus (lens action — converging or diverging light to a point)
A reflecting telescope uses a curved mirror; a refracting telescope uses a lens. How do Mirror and Focus connect?
Mirror then says: “A curved mirror and a lens have nothing in common and can never do the same job.” — is that right?
The link: reflect it or bend it — two ways to focus light to a point.
Bounce it or bend it, and the light comes to a point.
Capstone — build one optical instrument together
Three things light does. Bring in the cast member for each.
Bounce light back off a surface. Who?
Who do you bring in?
Bend light passing into glass. Who?
Who do you bring in?
Split white light into a spectrum. Who?
Who do you bring in?
The synthesis: reflect it, refract it, and disperse it — the behaviors of light in one instrument.
