Light - IR - 16+
This collection explores Infra-Red light, suitable for ages 16+
About Infra-Red Light:
Infrared (IR) is invisible radiant energy, electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz) to 1 mm (300 GHz). Most of the thermal radiation emitted by objects near room temperature is infrared.
Infrared radiation was discovered in 1800 by astronomer Sir William Herschel, who discovered a type of invisible radiation in the spectrum lower in energy than red light, by means of its effect upon a thermometer. Slightly more than half of the total energy from the Sun was eventually found to arrive on Earth in the form of infrared. The balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate.
Resources in this collection:
- Invisible Rays: A Catalyst article about the astronomer William Herschel who discovered Uranus in 1781. He became the first person since ancient times to identify a new planet. However, he is also known as the ‘accidental’ discoverer of infrared radiation. The article asks is this a fair description and can such discoveries really happen by accident?
- Pulse Oximeters: This resource from the Institute of Physics (IOP), describes how light can be used in pulse oximetry to measure pulse rate and oxygen levels in the body.
