Category Archives: Learning & Teaching

70,000 trees needed

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backyard‘70,000 trees needed to print graduation papers’.  This was a headline that I spotted in the China Daily (Thursday 24th April, 2014) while I was travelling in China last moth.  The article reported that the trees would be cut down to provide the graduation papers for this year’s 7.27 million university graduates in China.  Superficially, these are very large numbers, both of trees and graduates.  However,  China has a population of 1.38 billion, which is almost 20% of the global population, so the annual graduation rate is only about 0.5% of the population compared to about 1% in England.  There are concerns in China that there are insufficient graduate-level jobs for all of the students graduating this year, which is a familiar situation in the UK.  The idea of following the Finnish approach to higher education, with more universities of applied sciences than multi-disciplinary universities, is gaining ground in China.  In the UK, EngineeringUK has estimated the number of engineering graduates needs to double by 2020 in order to sustain our engineering industry whose turnover was £1.1 trillion in 2011-12, or 24.5% of UK turnover. The shortage of engineering graduates is reflected in average starting salaries that are 20% higher than for all graduate.

Back to those 70,000 trees; they would absorb between 2 and 20 kg of carbon dioxide per tree per year if they were not felled for the graduation papers.  Carbon dioxide sequestration by trees depends on their size, age and species, see for example the sources below.  The CO2 emissions in China are currently about 7  tonnes per capita, which is about the same as the UK and about 40% of the per capita emissions in the USA, according to the EDGAR or the World Bank, so that means that 70,000 trees might balance the emissions of between 20 and 200 graduates, i.e not many of the 7.27 million!

Sources:

http://www.forestry.gov.uk/pdf/6_planting_more_trees.pdf/$FILE/6_planting_more_trees.pdf

http://www.nature.com/news/carbon-sequestration-managing-forests-in-uncertain-times-1.14687

http://sustainability.tufts.edu/carbon-sequestration/

100 Everyday Engineering Examples

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bookletsSTOP PRESS – more than 100 Everyday Engineering Examples published in more than 40 lesson plans on a new webpage.

I have been including 5E lesson plans as part my recent posts.  These lesson plans are primarily for people teaching first-year engineering undergraduates, which is pulling me away from the intended focus of this blog. So, I have decided to publish all of the lesson plans that I have written & edited on a separate page.  There are more than 100 Everyday Engineering Examples in the more than forty lesson plans.  If that is not enough Everyday Engineering Examples then you can find more at ENGAGE

Now back to Realizing Engineering – we live in an almost entirely engineered world. Engineers, as a profession, are so good at their job that most people are unaware of their influence on society.  Look around you. Engineers will have designed the machines and transport infrastructure to supply most of what you can see as well as what you are probably sitting in and on.

The Royal Academy of Engineering has produced an ebook to expand on this theme of ‘Engineering in Society’ for first year engineering undergraduates but I think its suitable for anyone considering a career in Engineering.

Singing in the rain

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Followers of this blog might have deduced that I live within sight of the sea, which means that it is nearly always windy.  After a rain storm the streets of the city are usually littered with broken umbrellas.  I suspect that most of these belong to the many tourists that visit Liverpool, because local residents know that the wind will wreck any umbrella that you are brave enough or foolish enough to put up.

It is relatively straightforward to estimate the forces involved in holding an umbrella up in a gale by using control volume analysis.  The lesson plan below includes this Everyday Engineering Example together with two more control volume analyses.

Momentum 5EplanNoF5_momentum

The title of the posting is pretty tenuous this week: Gene Kelly sings ‘Singin’ in the rain’ without an umbrella in the film of the same name, see www.youtube.com/watch?v=D1ZYhVpdXbQ – well its difficult to be creative all of the time, or even some of the time!

See also the Everyday Engineering Examples page on this blog for more lesson plans and more background on Everyday Engineering Examples.

Reducing tension

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bubbleHave you ever tried to float a paperclip in a bowl of water?  It is quite difficult but possible if you put the paperclip on a piece of tissue paper and carefully place the tissue paper with the paperclip onto the surface of the water; then, using a pencil slowly push the tissue underwater and, with a little bit of luck and practice, the paperclip will be left floating on the surface of the water.  The surface tension of the water counteracts the gravitational force on the paperclip.  This is the same mechanism that allows some insects to ‘skate’ across the surface of ponds.

Detergent is a surfactant which reduces the surface tension of the water.  So, if you drop a little bit into your bowl of water the paperclip will sink because the surface tension is no longer sufficient to support it.

This is not an experiment to demonstrate in class because it is too delicate and too small for students to see but students can do it for themselves at home.  An alternative for demonstrating surface tension effects is to blow bubbles using a detergent solution.  These two ‘Everyday Engineering Examples’ are described in the lesson plan below and you can watch a video clip about it at www.youtube.com/watch?v=BRyQvGEQUt0

5EplanNoF1_fluids&their_properties

See also the Everyday Engineering Examples page on this blog for more lesson plans and more background on Everyday Examples.