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Ideas in a flash

Cameras have come a long way and can be used in class. Just be realistic about their capabilities, says Jon Tarrant.The bell is only five minutes away and the best way to summarise balanced forces is with yet another diagram. The inevitable: "Do we have to copy that?" is met with the equally inevitable: "Yes".

A quick-thinking pupil asks: "Can't we just take a picture of it and copy it later?" "You could if you had a camera," I reply, regretting the words almost before they reach the girl's ears.

A moment later camera phones are aimed at the board, books are packed away and pupils are heading for the door. Standing slightly stunned in a now-silent classroom I think Year 8 probably has the right idea, so I take my own picture of the board just in case their camera phone images don't turn out too well.

Digital cameras are often invaluable for recording classroom activities but there are certain features that make some cameras more useful than others. A decent optical zoom lens, with image stabilisation, is much better than a digital zoom. A wide range of light sensitivity (ISO) will prove invaluable in allowing pictures to be taken without flash. This is important because whiteboards' shiny surfaces reflect a large bright patch if they are photographed using flash. Not using flash without a high ISO setting risks blurred images unless the camera is held very steadily (try sitting at one of the desks and resting your elbows on the table).

If you want to photograph small or fast-moving objects then it is generally better to compose pictures with a viewfinder rather than the camera's LCD screen. Another useful feature is the ability to record motion picture sequences as a series of jpeg stills. Check the camera's instructions to determine whether its movie mode uses jpeg compression: if so then you will be able to extract each frame as a separate image and effectively treat the sequence as a series of pictures taken at 30 frames per second.

This allows rapidly moving experiments to be recorded in a way that will allow subsequent analysis. I have used it with sixth form physicists to view the movement of an oscillating spring and to track the movement of a ball-bearing in the "hunter and monkey" ballistics demonstration.

As for Year 8, as anticipated, those pictures were disappointingly poor so I'm glad I did my own to hand out later. Technology may be a wonderful thing but you do have to be realistic about its capabilities.

Jon Tarrant teaches science, with a physics specialism, at Jersey College for Girls.

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