I took a minor virtual trip through space and time the other day to computer- simulated Pisa in Italy, to witness Galileo dropping large and small stones from the leaning tower in order to prove they would hit the ground at the same time. Computer simulations are teaching aids that I have used extensively in the past, but the Pisa one triggered a crisis of confidence.

Supposing computer simulations had been around before the time of Galileo. What would an animation of large and small falling stones have looked like? The chances are that the big rock would have wheeched ahead of the wee one.

Once, I remember a pupil producing a poster for a unit on sight. He chose optical illusions as his theme, but hadn’t grasped the essentials of the concept. He drew what he saw telegraph poles that appeared to be different heights. But, when measured on his drawing, the poles were in fact different heights. And his lines that did not appear to be parallel were, on closer examination, shown not to be parallel.

It would be simplistic to say that the real world always scores over the virtual. My early days as a physics pupil were blighted by ticker-tape experiments that would have merited the tag “virtual”, in as much as they virtually never yielded meaningful results. Now the technology that has given us computers to run simulations has also made accurate measurement simple and accessible in the science class.

We should visit the real world regularly to show that the rules in the virtual one are in fact correct interpretations derived from physical observations and measurement. Imagine experiencing Europe through a computer simulation designed by a mid-market tabloid columnist. I think I’d rather jump off the top of the Leaning Tower of Pisa and not necessarily the virtual one.

Gregor Steele recommends going to www.carlukeguide. co.uk to experience the dangers of believing

everything you see on a computer screen