Lens Lab

A calibration ray enters the mystery glass at a known angle and exits at another. Use Snell's law to deduce its refractive index, then position and rotate optics to bend the beam into the green target ring.

• Read the incidence and refraction angles off the calibration ray
• Compute n = sin(incidence) / sin(refraction) and enter your value
• Drag and rotate mirrors and lenses to redirect the yellow beam
• Land the beam in the target ring to clear the level

• Daily puzzle, the same optics challenge for everyone today
• Practice, fresh levels each time

• Desktop: drag a mirror to move it; use the mouse wheel or the [ and ] keys to rotate; type your refractive-index guess
• Phone & tablet: drag optics with a finger and tap the field to enter your guess

• Read the calibration angles carefully, the index calculation is only as good as your measurement
• A higher refractive index bends the ray more sharply; expect tighter angles
• Set the beam's final approach angle first, then back up to line up the earlier bounces

Lens Lab is an optics puzzle about bending light, applying refraction and Snell's law to route a beam to its target.

• Skills: optics, refraction, Snell's law, light and lenses
• Best for: roughly grades 9–12 (ages 14+)
• For parents & teachers: a hands-on way to see how light bends through media.

Deducing a glass's refractive index from the angle a calibration ray enters and leaves is Snell's law used in reverse.

Measuring the material first, then steering the beam with it, is the original two-phase structure.

That sequence is how optics is actually done. The index is a property of the substance, not of the setup, so one measurement predicts every later angle — which is why a single calibration ray is enough to let you design the rest of the path on paper.

Lens Lab is an optics puzzle about refraction, Snell's law and beam routing. It's an original, free browser game made in-house for PlayPendium.

A free, original browser game on PlayPendium. No download, no install.