Nucleation
So who has tried 'that trick' with Diet Coke and Mentos?
Our "Guinea Pigs" wrapped up their two weeks of DIY.org challenges with one final "Rocketeer" badge blast off. We managed to catch it in glorious slow motion - I particularly like the sound track!
The reaction taking place is called Nucleation. The Carbon Dioxide that has been squeezed under pressure into the Coke is desperately looking for small surfaces or pockets on which it can form bubbles. The coating on the Mentos is covered in tiny divots, the perfect place - hence the reaction. Apparently there's also something in the artificial sweetener that aids the process.
Some people have turned this experiment into a bit of an art-form. Check out these guys: http://www.eepybird.com. There's also a Mythbusters episode that investigates the phenomenon (Season 4 Episode 14 if your interested in tracking it down).
This week we also spent some time documenting the 'base' that a couple of the kids had collaborated on in Minecraft for their 'Architecture' badge.
On the whole the two weeks we've spent doing DIY.org have been very successful. It has been highly popular and I've really enjoyed seeing everyone engaged in something they have chosen themselves. Definitely something we'll be incorporating across all our sessions!
Micro:Bits
Our new groups were introduced to Micro-Controllers this week. We started out with a discussion around how many devices/objects in their house contain computers (some people got up to 50!). Then we talked about the idea of inputs and outputs - using a dishwasher as an example.
Having mastered the basics we then got everyone coding a BBC Micro:Bit:
These little credit card sized boards are educational tools developed by the BBC as part of their Computer Literacy Programme. If any of you are wondering why the British Broadcasting Cooperation are developing computers this isn't the first time they have done so. Back in the early 1980's they released a very successful entry level computer called the BBC Micro (https://en.wikipedia.org/wiki/BBC_Micro).
The BBC have given away over a million Micro:Bits, 1 to every 11-12 year old child in the UK. They are programmed using an interface very similar to the Scratch language we learnt about last week. On board they have a range of sensors, both Inputs (2 Buttons, a Thermometer, Compass, Accelerometer) and Outputs (25 LEDs). They also communicate via Bluetooth and have a range of pins available to connect other modules. Several of our kids connected headphones using a special alligator clip adaptor we had made up.
We started with the basic 'flashing heart' project, getting everyone familiar with creating a programme and the idea that it had to be uploaded to the hardware before it would run. Then we let everyone loose to craft their own creations, based on a folder of different projects. We had 'music boxes', 'telegraphs', 'falling sprite games', 'rolling dice' and more. It was great - and awesome to see people tweaking the code and adding their own personal touches.
Next week most of our groups are starting a take-home project. Incorporating Woodwork, CNC, Soldering, LED's - it's going to be awesome!