Eyes on clocks and lenses

30th June 1995 at 01:00
Ever wondered how much electrical power you use boiling kettles of water? Or how much you might use if you had a tea urn instead? That might not be your easiest science investigation today, but with the Econometer, a simple and sensibly priced (Pounds 33) power meter, it might become that.

Just like a domestic plug-in timer switch, you plug it into the mains and your kettle or whatever into the Econometer. The unit then records the power used and shows it in kilowatts per week, as well as in the most important unit of all money. It certainly didn't take a week to find that a fridge freezer cost 49p per week to run. The unit uses a battery to keep a clock and display running so there's little risk of losing your readings. It doubles as a seven-day timer.

There's rarely any respite from the astonishing prices being asked for a good microscope. So the news of the BF200 series of a quality middle range, at prices nearly half those seen previously, is timely. At the top of this range is a binocular model with objective lenses up to x100, a desirable Abbe condenser and the flat, more even illumination of a fluorescent source at only Pounds 839. Or you can drop some features and get a lesser monocular model with a x40 objective, a disc condenser and with the same fluorescent source for an impressive Pounds 352.

The whole range has simple clip-on stages and should be suitable up to advanced level. And if you still have cash free, you can upgrade one to video-microscope status by using a small camera to pump the microscope picture into a television.

The gains here are considerable with a picture on the screen, you can show students exactly what you want them to look for every time. Or you can show how to count the cells in a haemocytometer, or watch live action such as the beating hearts of daphnia or the growth of yeast. You can even make your own microscope home movies by replacing the TV with a video recorder.

The costs are reasonable and start at around Pounds 150 for an adapter (with a built-in x10 lens, unusually) saving a loss of magnification. Then there's the camera costing Pounds 575 for a 13 CCD or the worthwhile bit more for the 12 CCD at Pounds 685. The expert's advice for video work is to choose the best you can afford. The best monocular microscope in the BF200 range costs Pounds 494. I'd be quite happy to skimp on the monitor practical advice suggests that a good, large TV is a better buy than a too-expensive monitor.

All these items are part of the manufacturer's Summer Bonanza mailshot, which includes a reminder about their "Colour Squids", a range of magnetic stirrers in a choice of colours and designs. Made of plastic, mains-powered and less cumbersome than the traditional design, these are as capable as you'd want for Pounds 64. With eight different "Swatch-like" designs to choose from, you'll wonder what to wear with them.

All the above are available from Griffin and George, Bishop Meadow Road, Loughborough, Leics, LE11 0RG. Tel: 01509 233344

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