Saturday Science with Physics Olympiad Across the World

This summer of 2024 I’ve been busy with Physics Olympiad students in Shanghai, China, as well as Cambridge (with Oxford coming up later this month). Ably led by the redoubtable Robin Hughes, a team of 14 of us flew out to Shanghai, courtesy of the ASDAN / ASEEDER charity, and I, with super assistance from members of the team, got students in front of Kleenex Clocks, Lycra Stress Gauges, Light Tunnel Angle Sensors and Micro:bit Electric Worms. We had 140 or so students from all over China as well as Shanghai, in four groups, two older (6th form) and two older groups (top of lower school), working in teams of 3.

The students were soon testing out Kleenex Clocks with water, and water solutions, measuring their varying speed along stripes of tissue paper. Some students tried out the effect of soap, the effect of sloping the tissue track relative to the horizontal, and one or two got the clock to sound an alarm beeper, relying on water conductivity when it reaches electrodes on the tissue.

The Lycra Stress gauges had been first tried out by students at Highgate School in London, with different material, showing how it could be used as a breathing sensor for patients with lung problems, with a capability of plotting a breathing pattern on an oscilloscope display. We moved ahead with stressing nylon sock samples with weights and soon some students noticed some behaviour which was not noticed in earlier tests: the readout on increasing and decreasing tension were slightly different – HYSTERESIS ! Also, quite a few of the Chinese students noticed that if you wait for a few seconds, the readout changes slightly, settling to a more-or-less fixed value. Very observant students – they did a really good job.

Our final piece of sensor testing was with measuring angle using a Light Tunnel Angle Sensor. A light tunnel sensor passes light up a dark polymer tube to a receiving phototransistor. The theory of this has been thoroughly studied by Ollie Breach, former Cambridge student and one of the Olympiad team members. Basically, the light transmitted decreases almost exponentially with the degree of curvature of the tube. Our Chinese students soon noticed this and started plotting logarithmic plots. But one group over-stressed – up to too acute and angle – their tube and gave it a slight kink. This had the curious effect of making the readout change with time for a while after changing angle, an effect which is present but tiny in tubing which hasn’t been over-stressed. Well spotted guys !

Finally, our student teams moved on to trying to win the Micro:bit Electric Worm Race. This involved understanding the Laws of Friction, the subtleties of the sliding motion of the worm, programming the Micro:bit microprocessor to control it, and the servos and their swinging levers and weighting the 3 segments to achieve motion, and, furthermore, fast motion. One is a 5-segment beast, which is a tad harder, but only one group managed to make this work. After a lot of testing, several worms were deemed worthy of entering the Electric Worm Race, and played off against each other along the floor.

Sedgfield School Student-Invented Projects

With the able Tom Williams, and Sedgefield School staff like chemistry teacher Rachel Lehain, we had six teams of 15/16 year old students at Sedgefield for three days. They first worked on thinking up a project, then making it, and then making it work and then measuring how well it worked, and then telling us all about it in a presentation on the last day. Our six project teams went on to produce:

• an emergency power supply (eg. for phones) relying on a football-rattle mechanism
  • the beauty of it being that it only needs one hand, so the other hand can hold the phone
• a self-rolling ball for exercising your dog, using a driven counterweight inside
  • with the curious 3-speed feature: moving either backwards or forwards slowly or forwards fast
  • and some ability to move itself around obstacles and carry on rolling, in a different direction
• a way of sensing movement during sleep. This used a Micro:bit microprocessor with its acceleration / gravity sensors to give the result to another Micro:bit. This worked and although Micro:bit comms do work, the team couldn’t quite get it working. So the team moved on then to an ingenious way of projecting a mobile phone picture onto an enlarge format on a screen: a mobile phone mini-cinema ! Good recovery from problems, guys !
• Another team had a go a greener illuminated road bridge. Making a 1.5m long bridge for radio-controlled cars fitted with their own specially made car-sensitive switches bridge, the team demonstrated how the cars, as they began to cross, activated the street lights to allow safe crossing, the lights switching off after the cars left the bridge, with good energy-saving.
• Another improvement to roads and pavements was invented and tested by another student team. They built a road-surface out of modelling clay with tiny holes. With a plenum chamber underneath, the team could suck water accumulating off the road surface with vacuum pressure.
• and finally, a team converted a toy radio-controlled tank by fitting a Micro:bit ultrasonic scanner on the turret of a tank for checking out small caves prior to potholing exploration by humans.

Inventing something new, eg. by adding imaginative sketches stimulated by brainstorming & random word pairs (Random Binomials) is an enormous boost to enthusiasm – even if it is difficult to do.  Developing R&D skills to try out stuff is very valuable.  And reinforces/adds to theoretical knowledge.