Tools/Sensors/description

Today there are hundreds of objects with sensors that respond to variables such as temperature and light. They enable us to measure force (in our weighing scales); deceleration (in our car air bags) and location (in GPS navigation). Sensors help us to investigate science. If you wonder about the G-forces you might undergo on a theme park ride, or how long it takes to cool a can of Cola, you are in the business of investigating science. Data logging technology now provides students with a tool to operate scientifically, solve problems in technology lessons, or analyse data in maths. All through the 1990's and ever since, UK schools have acquired equipment for measuring using sensors, largely because the National Curriculum (~1990) encouraged teaching science with technology.

Sensors^(tool) are obviously tools for measuring in science, but why might they be better than regular tools? Are they more accurate; more convenient or less costly? On these points alone, they are little better than a device such as a thermometer. Sensors and data loggers^(tool) are in part ‘special’ because they can display fast changes and measure with precision. A temperature sensor linked to a live graph can give an insight into how a cup of coffee cools. Analysing the data from that experiment provides learning opportunities - which can often be overlooked. Sensors extend the range of things we can measure - from timing a falling mass to recording human pulse changes during a race. Importantly, a live display of a changing measurement can provide students with a tacit understanding of what is happening. Nearby are numerous examples to evaluate what sensors bring to science.

Technology continually innovates and just sometimes, technology's ability to provide an automatic result is worth reflecting on. An accelerometer^(tool) gives an insight into gravity by providing the number 9.8 - a figure for the acceleration caused by gravity. Another sensor, called a light gate^(topic), can also measure acceleration but this result needs to be derived from measuring distance and time. Ultimately you have measured the same parameter but the advantage of using a light gate is that students must do the work to get to the answer. And that is very useful indeed. A further example may help: one type of breathing sensor 'integrates' chest movements to display a breathing rate on a screen. Another type of breathing sensor shows a wave of peaks as the chest moves. In the latter case, students need to count the peaks to obtain the breathing rate. An anaesthetist would find a direct readout of breathing rate useful while an engineer would find a direct readout of acceleration useful. A teacher however, would see learning opportunities in getting students to work things out.