Friday, 18 March 2016

Activity Idea: Angry Birds Catapult

For my final activity idea for the week - Angry Birds Catapult *-  I must give full credit to Phil Robbins, the STEM Ambassador who co-ran the Pixies Hill STEM Club with me for 2 years.  I realise Angry Birds is a bit out of fashion these days, but this is a great build-and-play and gives the chance to learn about so many physics principles while you do.

We actually ran this session with a different construction technique and using part of an egg box as the launcher for the catapult.  We set up blocks (previously used for Jenga bridges) and cotton reels (previously used for cotton reel tanks) for the angry birds (decorated ping pong balls) to be launched towards.

The children had great fun and it was a very popular session but, ever the engineer, Phil wasn't satisfied and worked on the catapult design to make it more reliable and robust.  Not only will this prevent upset due to breakages, it will also enable the children to learn more - if a repeatable action creates a repeatable outcome (such as pulling the launcher back at a certain angle sending the ball a certain direction) they are better placed to understand the relationship between the actions and outcomes.

The Angry Birds Catapult pdf * now shows how to make a sturdy and impressive catapult using the following:

We would love to hear of someone giving this a go. Please post pictures!  If you don't have access to a shot glass or the means to drill holes in it, you can always resort to egg box sections .....

*  I'm not sure why the annotations don't show up well when I look at this document online, however, when it is printed out, all seems to be clear and legible!

Thursday, 17 March 2016

Activity Idea: Cracking Bar Codes

This activity will open children’s eyes to something they take completely for granted ... bar codes. 

I’m including a pdf of my "Cracking Bar Codes" powerpoint slides you can use to show the children, or you could adapt the information yourself and just talk them through it. To be honest, the slides aren't great - I'm sure someone could come up with a simple worksheet which would take them through step by step, writing down 'their' bar code digits as they go. 

What you need:
  • items with 13 digit bar codes. (These are the most common, but there are shorter ones which work differently) 
  • paper and pen for each child to do the calculations.
  • A4 or A5 sized paper in 3 colours (optional).  


Try to include several items where the first two digits are not 50, and several from the same supplier / manufacturer.  You can include books and magazines.  Aim to have one item per child for them to then pass round, so nothing that could be damaged!

I also found it useful to have A4 or A5 paper in 3 different colours to write the bar code digits on for the children to hold.  I allocated 13 children one digit of the code and then sat them on a row of chairs to turn them into a ‘human’  bar code:
Digits 1,3,5,7,9,11  written on yellow paper
Digits 2,4,6,8,10 and 12 on green paper. 
The final 13th check digit was written on red paper, so when when they come to add up alternate digits, it is very clear which need adding together and they remember to leave the check digit out of the calculation.  I then called out for yellow or green to stand up so they were added up more easily. 

This activity is really only suitable for upper primary.  In addition, more able mathematicians can be set researching how the lines correspond to the numbers (not straightforward) and what kind of ‘errors’ would cause a barcode to be rejected (eg neighbouring digits swapped or a 5 misread as a 6).

The comment about ‘short cuts’ is to get them to think about whether they need to include the complete numbers throughout the calculations or just the units  - in my example do you need to add 30 and 81, or just 0 and 1? This could lead to an interesting discussion and a method of trying to search for situations where this would not be valid. 

The check digit (or check sum) concept is used throughout digital communications systems, and most people are completely unaware of it.  However, it is the kind of 'fascinating fact' that primary children will love taking home to their parents and then show off that they know how the calculation works. 

Wednesday, 16 March 2016

Activity Idea: Jenga Overhang

Activity Idea: Jenga Overhang

This challenge is to see how far you can get the furthest Jenga block to stick out beyond the edge of the table.  No tape, glue or any other materials can be used – just the blocks.  And it must be free-standing so no fingers used to counterbalance.

To make this work for a class / club, I recommend starting with 9 blocks for each team of 2 or 3 children.  There are 54 blocks in a standard pack, so you would only need 2 Jenga packs.  If you do have more, they can of course go on to create much more impressive structures. 

This doesn’t just entertain primary aged children – academic papers have been published on the maths behind the different types of structure.  These are worth a look for the images they include, which may spark off new ideas, either for you or the children. 

From 'Overhang' 2007 Mike Peterson & Uri Zwick

If you want to extend the activity you can include new challenges:

  • furthest overhang where there is only one block on each level, ie a slanting stack
  • highest structure with an overhang of one complete block – remember the blocks can go on end
  •  if you double the number of bricks can you double the length of the overhang?  Can you predict how much overhang you could get with 3 times as many bricks? 

I recommend taking photos of the structures, as they are bound to be knocked down whether intentionally or by someone bumping into them.  

Another interesting way to record the work is to encourage the children  to create a lifesize picture the structure by drawing round a block as a template. This may help them visualise the physics behind what stays up and what falls down and enable them to plan new structures more effectively. 

There is also a simple interactive game which allows children to explore the concepts virtually on the excellent NRich website called ‘Tower Rescue’.

You will inevitably find some children want to be more creative rather than functional with their Jenga blocks.  And why not?  In 2009 there was an artwork at the Baltic Centre in Newcastle called ‘Overhang’ and visitors were encouraged to take inspiration and make their own artworks from bricks.  

Have fun!  And do please post pictures, whether of overhangs or other works of art. 

Monday, 14 March 2016

Activity Idea: Cornflour Ooze

Mixing together cornflour and water to make a non-newtonian liquid is great fun – it’s not only the kids who enjoy this one!

You can choose to simply demonstrate it as in Mark Miodownik’s step-by-step instructions on the BBC website*.  I haven’t tried the trick of putting a raw egg inside a bag of the stuff as he did, and showing it doesn’t break, but I can imagine that is a really striking demonstration and would lead to an interesting discussion about what is going on.

There’s a simple but clear explanation of the principle of non-newtonian fluids on this website too.  Perhaps you could ask one child to read through it, and get the others to act it out, representing the cornflour particles or the liquid to help them visualise the effect.  

The alternative to just doing a demo is to ask the children to experiment by making their own, and to note down the ratio of cornflour and water needed to get the most effective mixture. This is what I did with my year 5 & 6 STEM club.  We used small cups (and stuck to volume measurements not weight) so we didn’t use up too much of the ingredients in one go. This also emphasised that it was the ratio that mattered, not the actual quantities.  Some of the children just wanted to ‘suck it and see’, but several were genuinely interested in honing in to the best ratio.  And one group were even prepared to work out their final optimum ratio by adding a bit more of one ingredient or the other at a time and keeping a tally so as to calculate the final ratio. 

I also encouraged them at the end to then make their work reproduceable by writing instructions to someone else to be able to make the optimum ooze, though I confess by this time, things were getting a bit messy. 

I told them that for the TV show ‘The Big Bang’ my fellow presenter had walked on a bath of custard ooze.  He was fine as long as he kept walking, but when he stood still he sank right in. We had a go with a small rectangular washing up bowl instead and used the best cornflour recipe from the previous experiments.  It wasn’t as good as a bath of custard, but I still got squeals of excitement and everyone wanting a go - in bare feet of course.

Finally, I asked a few of them to try making custard ooze and see if that worked as well.  And then to do some quick calculations to see how the cost compared.  (They all agreed it was more smelly!)

This activity filled the full hour easily, and was probably the longest clearing up time too.  I thoroughly recommend covering every surface with newspaper, and encourage the children to wear old clothes or aprons – and we weren’t even using food colouring. 

*Photos are taken from the BBC website

Activity idea: Jelly Baby Wave Machine

Jelly Baby Wave Machine

by Kate Bellingham

The jelly baby wave machine is not my idea – I found it on an excellent video with Alom Shaha.*  It is designed to be a demonstration for secondary school physics pupils, but I can thoroughly recommend this for an upper primary school demo, or a supervised make-and-do activity.

To make one 2m-long wave machine you will need:
  • ·      40+ kebab sticks.  (I had to be strict about handing these out – lots of temptation to poke each other with them!)
  • ·       At least 2.5m of duct tape (also known as gaffer tape or Duck Tape).  It is worth getting good stuff – chose tape that is very sticky and also flexible – parcel tape doesn’t really work.   
  • ·      90-100 jelly babies.  Let’s be realistic, some will split and others will get eaten. 

When I ran this activity in my after-school STEM club for year 5 & 6, we made two of these, with about 6 children working on each one – though ours were shorter due to the available space.

I would recommend starting by showing the opening of Alom’s video, then getting the children involved in the planning:
  • -       if the sticks are 5 cm apart and your wave machine is 2m long, how many sticks and jelly babies will you need?
  • -       How can you keep the tape tight enough?  (I didn’t have clamps, and just stuck it to the table, but you might find a more effective method.  We started with chairs, and then found someone had to sit on them …..).  To make your machine reusable, you could put your tape around a wide drinking straw, put a stick through that straw, and then fasten the stick to the table instead. 
  • -       How will you divide up the construction duties?  Alom mentions that the  exact distance between the sticks isn’t important, however, I found it is much clearer to see what is going on if they are fairly consistent.  Also, and perhaps more importantly, you will start to have problems if the sticks overhang more on one side than the other, or aren’t perpendicular to the tape.  You can make adjustments by pushing the jelly babies further onto the sticks to get the sticks to lie flat.  We found this was really important to make the machine work, and was quite time consuming (and the children started getting bored) so it is better to avoid this by getting the sticks on more accurately in the first place!
  • -       What experiments do you want to try once it is built?  Do you want to take measurements?  What with?  Eg stopwatch / timer on phone and tape measure / metre rule. 

I found children enjoyed exploring it in different ways.  Some just loved watching the ripples, while for others there was a great deal of discovery involved.  “How can the wave go along when the sweets just go up and down?”   “What happens if you start a wave at both ends at the same time?”  And even if you don’t get the children involved in making the machine, they can still get a lot out of playing with it. 

Please let School Gate SET know how you get on, and any other advice for running this demo / activity with primary school children.

* I’ve just discovered that this idea should probably be credited to Jonathan Sanderson who created it for ‘The Big Bang’ Children’s ITV show over 10 years ago. I was presenter on that show for the first two series and worked with Jonathan, so I am delighted to give him this credit.  He also filmed the youtube video with Alom demonstrating the wave machine which has now been watched by tens of thousands all over the world.

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