Optics
Flint-glass prism (more dispersion)
Dense flint glass (n≈1.66) refracts more and spreads the colours wider than crown glass.
Flint-glass prism (more dispersion) — interactive Optics simulation. Dense flint glass (n≈1.66) refracts more and spreads the colours wider than crown glass. Free browser-based virtual physics lab with live SI measurements and a guided tutorial.
Flint glass dispersion
Dense flint glass (n≈1.66) refracts more and spreads the colours wider than crown glass.
Flint glass has higher n and stronger dispersion than crown glass, spreading colors more in a compact prism—trade-off between size and spectral separation. This preset compares dense flint (n ≈ 1.66) to illustrate why instrument designers choose glass types deliberately.
- Higher n → more spread
- Dense flint glass
Investigation brief
Plan the question before you open the lab
The brief mirrors the prerendered page: driving question, competing predictions, variable roles, governing laws, setup, analysis and extension prompts remain visible and in this order.
Driving question
Dense flint glass has a higher refractive index (n ≈ 1.66) than ordinary crown glass (n ≈ 1.5). Does a higher-index prism deviate light more or less than a lower-index one, at the same incidence angle and apex?
Predictions to weigh
- Less deviation for a higher index.
- More — a higher index bends light more strongly at each face, producing greater total deviation.
- The deviation is unaffected by index.
Variable roles
What you set:
- Incidence angle θ₁ (°)
What you measure:
- Total deviation δ (°)
How the investigation runs
- Open the flint-prism preset and press Reset. This flint-glass prism has apex angle A = 60°, index n = 1.66.
- Enable the total-deviation readout.
- Set the incidence angle for each trial and record the total deviation.
Governing equation
Deviation Scales with Index — δ = θ₁ + θ₄ − A
At any fixed incidence angle and apex angle, a higher-index prism produces greater deviation — both Snell-law refractions (entering and exiting) bend the ray more strongly for larger n.
What the printable worksheet asks students to work out
- For one trial, compute θ₂ = asin(sin θ₁/n), θ₃ = A − θ₂, θ₄ = asin(n·sin θ₃), then δ = θ₁ + θ₄ − A, using n = 1.66. Compare to the table.
- Compare your deviation values here to the white-light-prism experiment's (same apex angle, lower index). Explain why flint glass's higher index produces consistently larger deviation at the same incidence angles.
Where this shows up beyond the lab
- Camera lens designers combine crown-glass and flint-glass elements (an 'achromatic doublet') to cancel out chromatic aberration — since the two glass types disperse color differently. Explain why using only one type of glass, however precisely shaped, can't eliminate color fringing on its own.
- Flint glass spreads a wider range of colors than crown glass for the same apex angle (more dispersion, not just more deviation). Explain why higher-index glasses like flint tend to disperse light more strongly across the visible spectrum.
- AP Physics 2 — Unit 13: Geometric Optics
- General High School Physics — Light & optics
- NGSS High School Physics — Wave properties
- Welcome to Flint Prism
- Select the prism
- Press Play
- Strong dispersion
- Open the Properties panel
- You did it!
Open the interactive simulation to build the scene, press Play, and explore with live measurements and a guided tutorial.