# ICT - Capturing magic

9th January 2009 at 00:00
Inexpensive digital cameras can create eye-catching lessons, discovers Jon Tarrant

One of the best ways to engage pupils is to show them something amazing that they haven't seen before. A highly magnified picture of a dust mite, taken using a scanning electron microscope, tends to get a great reaction, but the equipment used is hardly likely to be found in an average classroom.

If your budget is more realistic, Casio's high-speed digital cameras are more affordable (about Pounds 350), and can be used by teachers and pupils to inspire memorable lessons in subjects ranging from mathematics to PE.

The cameras can capture up to 40 and 60 still pictures in a single second respectively or many hundreds of frames per second for moving images. They look and behave like any other advanced compact camera except that they excel in capturing sequences of images, recording events that happen too quickly for the eye to observe, whether it is a collision between marbles to illustrate the conservation of momentum or the anatomy of a high- jumper's leap.

They can also be used to answer such questions as: "What shape of curve is created when water is squirted from a syringe?" "What are the elements of a good tennis serve or shot-putt throw?"

Able pupils can be set the task of identifying the sorts of high-speed events that can, or cannot, be photographed using these cameras. For example, would it be possible to photograph a bullet cutting through a playing card (one of Harold Edgerton's famous high-speed pictures)? The answer involves working out the time it takes for a bullet to move across the face of the playing card and comparing this with the interval between pictures. Probability can then be brought into play.

High-speed cameras can also be used as timing devices, allowing the speeds of objects to be calculated from the distance moved between frames. You could record a remote-control model car to determine whether its terminal velocity is proportional to a full-size car's top speed in the same scale as the physical dimensions of the model itself.

If all that sounds too much like hard work, then photography pupils can use the same cameras to capture unusual and potentially beautiful scenes that the eye would never otherwise observe, such as the moment of impact when one coloured liquid is dripped into another.

Jon Tarrant is head of physics at Hautlieu School in Jersey and is the island-wide VLE co-ordinator for Jersey's secondary schools.

KEEP THEM THINKING

SEM dust mite image: http:axiom.anu.edu.au~lukeimagesmitesdust_mites_pin.jpg

Information about Casio high-speed cameras: www.exilim.co.ukhighspeed

The work of Harold Edgerton: http:techtv.mit.educollectionsdocedgertonvideo.

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