Smartphone light sensor experiments
5 classroom-tested activities with the free FizziQ app, for high school, middle school, middle and high school.
The ambient light sensor gives the illuminance in lux. FizziQ uses it as a lux meter; on iPhone, which has no accessible light sensor, the camera takes over. Instruments in FizziQ: lux meter. Read the glossary entry on the light sensor.
Each activity below has a protocol, expected results, scientific background, a printable PDF handout and a QR code that opens it directly in the app. FizziQ is free on iOS and Android, needs no account, and shows no advertising.
Activities
- Beer-Lambert law with a lux meter High school 25 min
Using the smartphone lux meter in FizziQ, students measure light through stacked tracing paper and plot ln(T) against N to verify the Beer-Lambert absorption law.
- Illuminance: the 1/d² law High school 35 min
With the smartphone light sensor, students measure illuminance at increasing distances from a lamp and verify the 1/r² law in FizziQ. High school, Android.
- Straight-line course, no compass Middle school 40 min
Walking 150 steps blindfolded, students hold a heading with the smartphone gyroscope and accelerometer in FizziQ, then judge the sensor drift rovers face on Mars.
- Photoplethysmography of a finger Middle and high school 25 min
The phone camera and its LED become a photoplethysmography sensor: the FizziQ colorimeter records green light variations and yields heart rate, on smartphone.
- Diffusion and retroreflection Middle school 25 min
In a darkened room, the phone's lux meter compares the light returned by dark clothes, light clothes and a reflective vest: FizziQ makes retroreflection measurable.
Other sensors
accelerometer · microphone · magnetometer · barometer · gyroscope · camera · GPS · external sensors