Table of Contents

Dr. Seahorse Sees the Invisible

Dr. Seahorse Sees the Invisible

Brief Description

The Sun provides light and heat. You can see the light, but what about the heat? In this experiment, you can make the heat visible.

Materials

Mobile phone with built-in camera

TV remote control

Learning Objectives

The existence of different kinds of light made of many different colours, some visible and others invisible to our eyes.

Background Information

Sunlight is a mixture of many different colours. You can see this when the sunlight is refracted by raindrops - a rainbow appears in which all of the different colours are neatly arranged. The Sun also emits ‘light’ that our eyes cannot see, such as infrared radiation. Our eyes are not capable of seeing infrared rays, but we feel them when they heat our skin.

Invisible infrared light is also used in remote controls to transfer signals to the TV. The funny thing is that, unlike our eyes, a mobile phone camera can ‘see’ this light! The camera can also see the infrared light coming from the Sun. However there’s so much visible light compared to infrared light that it’s difficult see the infrared light. Therefore, astronomers wanting to observe the Sun and stars in infrared light must use special cameras.

Press any button on the remote control and look for a light flashing in the front of the controller. Repeat this, but this time look at the flash through your mobile phone camera. (Image 1) What do you see?

Keywords

Light Colours Invisible Infrared Signal

Source

NRC Handelsblad (5 May 2012)

License by-sa