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# College students learn a valuable lesson in engineering

21 May 2014

Matt Haslett and Emily Hutchison, two engineers from TWI in Cambridge, held a welding with chocolate workshop at Linton Village College to enthuse young minds about welding and engineering. The workshop was very popular and amongst the excitement of melting and welding chocolate some valuable lessons were learnt.

Building bridges by welding with chocolate is an innovative and fun way of demonstrating welding and engineering principles in the classroom or at home.

First the students tested a simple bridge using one bar of chocolate spanning the distance to be crossed, measuring how strong it was by adding weights until it buckled and broke under the strain.

They then made a box girder bridge by melting the sides of two pieces of chocolate, welding them into a V-section and welding two V-sections into a box shape that should in theory be much stronger than a single piece. Students had great fun guessing how much extra weight a box girder would be able to take and testing their new bridges until they broke. It certainly brought out their competitive sides!

Matt and Emily therefore demonstrated the difference in load ability by 'welding' chocolate bars into a box girder and comparing the weight this girder could take in comparison to a chocolate plank. Students had to guess:

• How much more load could be added to a box girder bridge compared to the plank bridge?
• If and when the bridge breaks, how would it break
• Why their chocolate box girder bridge was stronger?

Many of the students expected the box section to be 4x stronger than the single bar of chocolate because it had 4 bars. However, they found through their experiments that it was normally at least 10x stronger because of the better design of the box structure. Vertical bars are much stiffer so bend less easily than the horizontal bars. This is why engineering is useful and necessary in everyday life. A well-engineered construction can save substantially on materials and costs and ensure the safety of structures.

Students thoroughly enjoyed the experiment and commented:

'This was a different approach to learning about engineering.'
'I never knew milky bars were so strong.'
'I never knew that chocolate could be welded.'
'It was a great way to teach us about what TWI does.'
'We learnt about how you can use welding to make rockets.'
'It was a really fun day.'
'I liked the fact that we won and got the most weight on the chocolate tube!'

TWI's Younger Members' Committee (YMC) supports young engineers in their professional development and promotes welding and joining technologies in schools, colleges and universities.

For further information please email the YMC ymc@twi.co.uk

View a video of Welding with Chocolateon YouTube.