Hi-tech sensors measure up in the brave new world of classroom experiments

7th January 2000 at 00:00
Roger Frost takes a look at the state of data-loggers and looks ahead to those products about to enter the fray

There is a branch of technology where the product is not words, pictures or Web pages but nevertheless offers to shift what happens in classrooms up a level. Here electronic devices or sensors take readings in science experiments as the computer displays them on a graph. It is fun, enthralling and a core school activity.

In primary schools, sensors are handy tools for learning about graphs and measuring. Take a light sensor and you can measure the brightness of the room all day and night. You can then print out the graph and get the pupils to figure out what happened when. At this time of year you can do the same with a temperature sensor to see when the heating comes on and off while a sound sensor can be extra good value - if you leave the room you can check if the class has been quiet. Or place it on your chest and you may pick up a heartbeat. And there are other forays into electronic measuring - seeing how things cool, which clothes keep you warm.

While some primaries aim for top-of-the-range, many will be happy with as basic a kit as possible. Price is a good guide to what's appropriate, with kits starting at pound;100 and rising to pound;200. Those with Lego's Robolab system will be interested to hear they can now use it for logging using new software.

The sky becomes the limit in the secondary school, however. Quite a number of science departments have the class set of temperature sensors and light gates - something that seemed unattainable a few years ago - and, using these, pupils investigate temperature changes and measure the speed of trolleys, activities now highlighted in the science curriculum.

With a few more sensors you can do some interesting demonstrations: for example a distance sensor lets you make distance-time graphs as you walk towards it, maybe using pulse and breathing sensors to judge effort involved, while an angle sensor monitors a pendulum's movement. Each give the instant results essential to demonstrations.

Going beyond this level you can demonstrate events that were previously hard to capture, such as electromagnetic induction, sound wave beats and acceleration changes, using the super-fast systems from US supplier, Pasco (see Online, October 15).

But beyond the basic experiments and demonstrations lies a peculiar void, best called "now-what?". It involves wondering how to use hard-won resources to achieve something meaningful.

One suggestion is to use technology to investigate science - to monitor say, how ice freezes and what affects this. A second is to use the tools built into data-logging software to analyse the data - finding out say, how much warmer some fabrics are or whether it is the glass or the stopped draughts that makes double glazing work. In short, unlike other technology, data-logging produces more than a graph: how you get to the results is part of what you can learn from it.

If that seems bizarre, consider the alternative: replace the thermometer in an old experiment with a computer and it's debatable whether pupils will learn anything new. Ask and they'll say they already knew that a well-wrapped beaker cools more slowly than an unwrapped one. They'd rightly be puzzled as to why they used a pound;1,500 computer instead of a pound;1.50 thermometer.

Travel beyond the void and you'll find a lot of interesting, challenging investigations. As an IT inspector once said: the point of using information, communications and technology is to make hard work, like analysing graphs, a lot more accessible.

More than ever, secondary schools looking for data-logging equipment have a vast range to choose from. And although it isnormally hard to mix and match, a truly practical tip is to see if Logotron's Insight software will work with what you have and what you're thinking of buying. As a third-party product, it works with many different kits and will help you to shop around to buy what's best today.

Roger Frost is author of Data Logging in Practice, available from the Association for Science Education. A store of experiment results can be found on his website at www.rogerfrost.com

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