Investigate the transmissive and reflective characteristics of infrared light as compared to visible and ultraviolet light.

A person holding a piece of clear acrylic between the FLIR ONE™ camera and herself, blocking infrared light on the left side of the image.

Visible light passes easily through clear glass, water, and clear plastics. Ultraviolet light does not pass as easily through water or glass. How does infrared light behave? Try using the FLIR ONE thermal camera and the Thermal Analysis app to look at a scene through an open window and then through a closed window. Compare what you see with your eyes to what you see with the camera. Try using the thermal camera to observe a person through a black plastic trash bag.

What other materials can be investigated? Find a warm object such as a person, a plugged-in power adapter, or a computer. Use the infrared camera to observe the object, then place different materials between the camera and the warm object. Try placing paper, aluminum foil, clear acrylic, glass, plastic wrap, sunglasses, thick and thin sheets of cardboard, black cotton cloth, white cotton cloth, and any other materials you can think of between the camera and the object.

Similarly, you can investigate reflection. Look at your thermal reflection in a variety of surfaces, such as smooth glass, cinderblock walls, book covers, the surface of water in a bowl, a mirror, and other surfaces you can find.

You can get an idea of how much visible light passes through or is reflected from different materials by using a Light Sensor. Similarly you can investigate the amount of UV light using a UVA sensor. Use the sun as a source of UV light if you can go outside or use a UV light bulb. Do not look directly at the sun, and avoid looking at an illuminated UV light bulb. Compare your results from sensor readings to what you see with the thermal camera.

Download experiment instructions by Rhett Allain, author of Geek Physics, for a more formal exploration.

Experiment Download
[adopt_orphan]Infrared Light vs. Visible Light[/adopt_orphan] Student Instructor