LIGHT - Example Introduction:

Light is what's called an “electromagnetic wave”, just like radio waves, microwaves, X-ray waves, etc. Electromagnetic waves typically start when an electric charge jiggles back and forth.

Depending on the “frequency” of the electromagnetic wave (on how scrunched together the peaks in the wave are), you get different kinds of waves.

For example, radio waves have a low frequency - that is, the peaks in a radio wave are quite a long way apart and they are not visible to humans).

Next come:

• microwaves (with peaks closer together),
• infrared light.
• visible light spectrum (i.e. the different colours of light that people can see)
• ultraviolet light
• x-rays
• gamma rays (higher frequency still - the peaks are still closer together).

Sometimes you'll hear that light is made of photons. What that means is that when light is absorbed or emitted, the energy in the wave comes in lumps rather than waves.

The size of those lumps (or 'quanta') of energy depends on the frequency. The higher the frequency the more energy per photon.

As light interacts with the things around us, its properties can be become altered. By studying these changes, we can find out a lot about light and the objects that it interacts with.

For example, through the study of light we can discover what stars are made of, watch the processes that occur in living cells, and even look back in time to see things as they happened millions of years ago.

The human body has a variety of ways (senses) to detect energy.

• Your ears perceive certain frequencies of longitudinal waves as sound.
• Your skin, mouth and tongue can perceive thermal energy as hot or cold.
• Your eyes perceive certain frequencies of electromagnetic waves as light.

Using technology, we can now 'see' things that would normally be invisible to us.

One amazing thing is that the human body can detect the wavelength of visible light by the colour that it appears to be.

What a magnificent energy sensing instrument the human body is!

Don't worry if it still seems a bit complicated or confusing - Light, is difficult to understand:

• IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY:Light - What do blind people see

Being a good light detective is as much about how we see as what we see.

1. Test using light to classify materials as transparent, opaque or translucent, based on whether light passes through them, is absorbed, reflected or scattered

- Observe and describe how the absorption of light by materials and objects forms shadows and how the effect of the relative positions of the light source and the object affect the shadow.

- Perform experiments to gather evidence about how light travels and is reflected.

- Refer to existing research and identify how the properties of light are used to solve problems that directly affect people's lives

- Apply our new scientific knowledge about the absorption and reflection of light to solve problems that directly affect people’s lives.

• IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY: Viewpure Light from the sun