Maths and Science Day 2012 – Spaghetti Bridges!

The 21st of July 2012 played host to the annual Maths and Science Day. Maths and Science Day allows all year 8 students to work off timetable for the enire day, working in teams to solve scientific and engineering challenges. Deviating from the task of previous years (parachutes for eggs) the teams this year were set the challenge of building a bridge that covers a 50cm span using only spaghetti and hot-melt glue.

The girls got straight to work, ably assisted by Yr 12 students. They worked really well together, with each student contributing to the team design.

Eventually, when all the bridges were built it was time to test them. Bridges were gradually loaded with more and more force until they broke. The winning team would be the one with the highest load:weight ratio. After a nailbiting testing session, a winner was declared – Team 25 with a load:weight ratio of 11:1!

Bridge 25 – the winning bridge!

After this the teams got together to create a poster explaining their design, the science behind the engineering of bridges and an evaluation of their bridges performance. Team 10 were judged to have the best poster for their careful analysis of why their bridge collapsed with only 10g on it!

A spaghetti bridge, inspired by a Warren Truss bridge

Every team worked incredibly well – their bridges may not have held a great load but they all produced a structure which they could be proud of.

Testing bridges

Funding for the purchase of the hot-melt glue guns and the spaghetti was kindly provided by the Institute of Physics (IoP) http://www.iop.org/ , so many thanks to them for making this event possible.

Tilbury Power Station

On 7th February 48 students from Year 11, (accompanied by Mr Bilton, Miss Vine, Mr Pimentao and Miss Gilleece) travelled to Essex to visit the npower-operated Tilbury Power Station. The students study the generation of electricity as part of their course, so this was an excellent opportunity to see where it all happens. The Tilbury site was originally a coal-fired power station, but this year it switched to using biomass as the fuel source, as part of a programme to be ‘greener’ and depend on renewable sources.

Tilbury Power Station

The biomass used at Tilbury is wood pellets, produced from the sawdust and waste of the Canadian lumber industry, so it’s a good use of a material that would otherwise just be wasted. It also has less impact in terms of CO₂ production than coal, because it’s not burning carbon that’s been locked away for millions of years.

Properly kitted out in hard-hats, ear defenders and high-visibility jackets the students were taken on a tour of the power station, at one point standing inside a 65m furnace which reaches temperatures of 1500ºC (luckily for the students it wasn’t on at the time…). The scale of the facility is hard to imagine, but it gives you an appreciation of engineering behind the process.

Safety first - hard-hats and ear defenders!

The process of electrical generation is actually remarkable simple. When the biomass arrives it is crushed and then blasted into the furnace where it burns. The furnace is lined with pipes that contain ultra-pure water. As this water heats up it turns to steam. This high-pressure steam is used to turn turbines (converting heat energy into kinetic energy), and the turbines rotate an electro-magnet within a coil of wire. The movement of a magnet within a coil of wire creates the electrical current (thanks Faraday!) and that’s all there is to it.

Generating electricity - what's happening inside?

The students were also able to study some of the chemistry and biology surrounding the issue of power generation. Using conductivity meters the students recorded how many dissolved ions and minerals were in drinking and filtered water. They then compared it to water that had been through an ion-exchamge resin and were surprised to see that there were no ions left at all. This super-pure water (which actually tasted a little bland) has to be used in the power station to prevent damage to the pipes (picture the inside of your kettle..). The students then had a look at the local water quality by pond-dipping and looking for indicator species; species that tell you how clean the water is by their presence or absence. Having found a variety of insects including Common Backswimmers, Damselfy nymphs and Diving Beetles (and even some fish) everyone was surprised to conclude the water so near a power station was actually good quality and supported a diverse community.

Damselfly nymph - this larval form indicates good water quality

Common Backswimmer - this insect swims upside down

The students had a really good time and certainly learned lots about where their electricity comes from and how best to manage our energy resources so that we can live in a sustainable and ecologically-sensitive way. Many thanks too to the staff at the power station for giving us such an enjoyable day!