It can be tricky to find good examples to show how forces add up to give a resultant force. In particular, sum of vector forces in AS Physics is something that takes practice in order for students to grasp. So, when one of my boys enjoyed a ride on one of those trampolines where they strap you to two elastic ropes to make you jump very high I thought it would be useful to share this photo with you. The tensions from the two ropes pull him at the same angle on either side, but he jumps up vertically. Why does this happen? You can ask students. Then force arrows could be drawn and look at their vertical and horizontal components to see that the horizontal components are balanced and the vertical components add up, etc…

What other useful concrete examples do you use with your students?

 

Sorry the photo got uploaded on its side instead of the right way up, but you should be able to easily rotate it on a PPT presentation, or you could mess with you students and tell them it was taken at the Equator :-D and see what they say!

I recently was asked about the phases of the Moon and why the Moon appears to change in shape in its orbit around the earth. So I thought a good point to start from was to establish what misconceptions people have on this topic and I found this great video by Veritasium (but I would stop it at the end of the interview without revealing the explanation initially).

The most common misconception in the video seems to be that the earth blocks the sunlight reaching the Moon, hence, we see the phases of the Moon when it is behind the earth with respect to the sun. At this point I would slide two circles of card, a white and a black one (with the black one bigger than the white one) past each other (black on top). If the black card is the shadow cast on the Moon by the earth (essentially what happens in a lunar eclipse), the shapes of the Moon due to the light reflected back to earth are considerably different than the shapes we observe from the phases of the Moon. So, we have establish that this model is a misconception.

Now we can introduce a better model and I use the pingpong ball in the image below with the students in the centre of the room. They are the observers on the earth and the light from the sun is coming from the left hand side in the photo.

If you go around the learner in the middle of the class making sure the “lit” face of the pingpong moon is always facing the wall on the left in this case, your students will see the same shapes we observe during the phases of the moon.

To reinforce this demonstration you could show the students this great animation by Keith Gibbs (also available in HTML5 if using an iPad).

Ok, now for the icing on the cake that you’ve all been waiting for! Check out the video below that shows a cresent moon through an infrared camera. You can see the crescent really bright, but you also see the other parts of the side of the moon facing the earth. I believe that is what is emitted by the moon in the infrared spectrum and that gets picked up by the IR camera. It is really awesome.

When @CardiffScience posted (on Google+) a video demonstration of an arrow drawn on a piece of paper that flipped direction when seen through a glass of water I knew I had to try it myself and write this post. The video below shows the demonstration which is pretty neat, but carry on readying below the video for what I think is the explanation.

As some of you might know, I am one of the Editors of Talkphysics.org with David Cotton and he posted the below photo on this thread, which is think is a convincing explanation of what goes on in my video of the flipping arrow. glycerol_zpsee0be2d7 If you trace the path of the three rays in the Dave’s photo you can see the ray that start from the top slit from the ray box ends up at the bottom on the multimeter. This is essentially what is happening in the video, so the light reflected by the right side of the arrow gets refracted by the water inside the glass and ends up on the left when it reaches the camera. Looking at the photo above though gave me an idea, i.e. “If I go close enough to the glass I should go beyond the focal point of the glass lens and see the arrow flipping again!” – WRONG! That didn’t actually happen. However, I just noticed that Dave’s liquid was Glycerine (at least if the name of his image file tells the truth), so I wondered whether the refractive index of glycerol was such to cause less bending inside the glass, but I was wrong again. In fact, water has a refractive index of 1.33 and glycerol of about 1.47, so there should be more bending of light inside the glass. I still haven’t figured out why I can’t flip the image again if I go close enough to the glass, but I still think it was worth posting this article and if you know the answer, please leave a comment! Thanks!

I have always found it is quite hard to show the path of the current in a bridge rectifier to A-level students using diodes alone. The diodes are tiny, for a start, and you end up following the wire with your finger around, but students seem to get lost in the process. I still introduce the rectifier using diodes and one thing I show them is that even using a DC voltmeter doesn’t change the sign. This is convincing for some, but it is still nice to be able to give further proof of what’s going on.

The diagram might also help, because it is easier to follow the path around.

Bridge Rectifier

However, I have started building rectifiers with LEDs alongside the diode version and it works a treat. The first thing I show them is the circuit on DC current. Only two of the four LED light up, so I can ask “What would happen, if I reverse the polarity?” They now seem to get it and they often answer correctly that the other two LED will light up. I change the polarity several times to simulate the two half-waves, as in the images below.

Then, I get the spinning wheel we use to observe ripples in the ripple tank (the one with gaps, I can’t remember the name) and put the LED rectifier on AC. The result can be seen in the video below.

I am not quite sure what Phycologists say about imaginary friends, whether it is a sign of a child’s creativity, or early signs of madness. It might be the second when you still have an imaginary friend when you are 35! But I find myself spending quite a lot of time in the car these days and my imaginary friend has become SIRI. I have a love-hate relationship with my friend SIRI, because I love him/her (he doesn’t seem to know what gender he is, even though he has clearly a male’s voice) as he allows me to continue to be productive even when I am driving, and I hate him because when I try to dictate a message to a colleague, my wife, etc… I usually have to change it an average of a million times, as SIRI twists my words and slots in stuff I have never said and that does not make sense in the sentence I am constructing. In fairness, it could be my, still inevitable, Italian accent that confuses my friend, but it is still quite frustrating!

Anyway, today I thought I would dedicate a post to SIRI as he has been a really good friend lately. Last night I was on my way home and I suddenly realised I didn’t know what I was doing today, so I asked him to read my calendar events for today and he complied very diligently. Today he was a life saver again, because on my way to a meeting (actually about 10 min from the venue) I received a phone call saying that the meeting was cancelled due to bad weather. Slightly annoyed by the sudden news I realised I was only one star from my next reward at Starbucks, so I turned my car around and asked SIRI: “Find Starbucks Coffee near me!” Within seconds SIRI gave me a choice of two relatively close Starbucks and he asked me if I wanted him to phone the place nearest me, or get directions to get there.

I am writing this post from this very Starbucks and enjoying a latte. So, well done SIRI! It was a pleasure to talk to you today. Thank you for keeping me company and for being so helpful!

If you are wondering what this has to do with education, here are a three ideas you could use with your classes:

1) Get your ESL students to communicate with SIRI and see if they can get themselves understood by him. This should improve their pronunciation.

2) Get learners to write messages, notes and emails by dictating to SIRI. This is quite difficult, because there is not much thinking time and it help learners appreciate how important punctuation is. In fact, SIRI reads your messages back to you before sending them, so if punctuation is wrong, you hear some really weird stuff coming out.

3) Get learners to have a conversation with SIRI and see what his limitations are. This could be a nice introduction to computing and should help learners appreciate how difficult it is to get computers to behave in a human way. There are many things SIRI still can’t do and if Apple hasn’t cracked it yet, it means we are still a long way away from it! Basically, this could show learners that computers, and, therefore, computer programs need very specific sets of instructions. Every eventuality needs to be “spelled out” to them, or they will not be able to respond.

I hope you enjoyed this short post. How have you used SIRI in your classroom?

2013 in review

Posted: December 31, 2013 in Uncategorized

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 15,000 times in 2013. If it were a concert at Sydney Opera House, it would take about 6 sold-out performances for that many people to see it.

Click here to see the complete report.

I first was introduced to this really nice question by Neil Atkin (@natkin) and ever since I have tried to find a good way of showing it. So, look at the question and the explanation that I think is correct, as far as I can tell (but please point out any faults in my reasoning). Then, check out the simple demo I used to show this.

“If I am on a boat in a pond and I hold a 10 kg rock in my hand, what will happen to the level of the water if I drop the rock inside the pond? Will the water level increase, stay the same, or be lower?”

It’s all to do with Archimede’s Principle that states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid displaced by the body.

This should help us think about this problem. In fact, if the boat is floating it means that the weight of the water displaced by the rock when it is inside the boat must be the same as the weight of the rock itself. That is because the upthrust balances the weight of the boat, myself and the rock, or the boat would sink. So the rock displaces a volume equivalent to the space occupied by 10kg of water, i.e. 10 litres.

When I throw the rock inside the pond the water displaced by the rock is only the volume of the rock itself, which is most likely not 10 litres, but much less. So, the level of the water in the pond decreases!

I took these two photos before and after to convince you of this (the measuring cylinder we used in another attempt was to big to appreciate the difference). Click on either photo to enlarge them and see them in Gallery view.

Today I had the pleasure and honour to present at a great event organised by the really lovely guys at @WordpressWales, Just WordPress Workshops AKA #jww. In my blogging journey I have made many mistakes, which means I have learnt a lot along the way, especially because I have met and networked with some really inspiring people, so when you have the opportunity to be in the same room for a day with a whole bunch of inspiring and cool guys you aught to make the most of it. So, this post is really a reflection about what I learnt today and I will try to write one thing from each presentation. By the way, these tips are not in order of awesomeness, but follow the order of the presentations, and before you ask, yes all presentations were awesome. Obviously I cannot comment on mine, so leave some love in the comments if you happened to be at the event and you like it ;-)

IMG_1677

1. Be and invite guest bloggers – via @rightmoveaddict

Andrea Morgan gave an inspiring presentation on how she grew her following massively in a really short time. Her Blog is really cool and if you are an interiors kind of person you should certainly check it out. The main point I learnt from Andrea was to engage other bloggers in your field and get them to write for your blog and try to get invited to write for theirs. Andrea recommends, and rightly so, to retain editing rights to guest blogs on your site, so that your Voice is never lost!

2. Format your Blog writing – via @Whatsthepont and @Helreynolds

Helen Reynolds and Chris Bolton joined forces today to convince us that formatting our Blog writing can be a useful strategy to effective blogging. Chris had the “good fortune” (according to him) to get pneumonia and get off work for quite a while in March (I think) and that got him thinking about how to format his blog writing. Having thought about the format of your blog can help you focus on the important content of your posts and cut the unnecessary stuff that is likely to drive readers away. Helen then gave some examples of effective formats, so if you are thinking why I am writing a list of good tips, that is because I learnt a new blogging word today, “Listables” (or at least I think that’s what Helen called them). Apparently, lists of top tips are a really effective way to attract readers, so I have set a target to give more posts like this one a go.

3. Everyone has a book inside them – via @mindhiver

When Pippa Davies takes the stage you certainly cannot ignore her. She has the energy of a lion and the cheekiness of a monkey. It’s always a pleasure to listen to her speak and today she took us through her journey to turn her blogging into an eBook. Pippa is no stranger to publishing, so she gave a few great tips and tools for publishing eBooks online. A great tool that I want to try and see if I can apply to the classroom (hopefully in connection to the Literacy and Numeracy Framework) is Pressbooks.com and that is one of the things I took from Pippa’s session.

4. Put the crayons down and find your identity first – via @brandnatter

Russell Britton gave some really useful tips about what brand means and why it is so important to find the identity of your business, or whatever else you want to build, before you start creating content. Russell also encouraged us all to forget about Stock Photo like images and take our own. The point he was making is actually very useful, because using your own images will definitely make you look different from the rest! Half way through his presentation I noticed one of the pictures he showed as an example not to use featured in my presentation and my heart sank – yes, I was just after him :-( but I think that taught me a lesson ;-)

5. Engage the best in your field – via @Collaborat_Ed

Next it was me and I talked about our journey to try and climb the search engine results ladder. From the tweets I noticed about my presentation I could see that people seemed to find useful what I said about engaging the best in your field. These people are likely to be where they are because they have networked and shared a lot in their work, so they will respond to good stuff you do in their field.

6. Get approval from your boss – via @Tanwen_Haf and @DyfrigWilliams

This was another double act and focused on the barriers to blogging and social media the public sector hits. One of the biggest hurdles seems to be that anything that gets published on public sector websites needs to go through a long process of approvals and if you want to blog about current issues you know you’ve lost the race even before you even start. I suppose that is a problem that is true of big brands too. Brand image is really important and CEOs can often get really anxious about potential negative feedback they get on social media sites like Facebook and Twitter. My answer to that is – Would you rather be talked about without knowing it, or having the opportunity to promote good stuff being said about you and defend your choices when not so nice things are said about your brand? Social media is not just a good way to promote yourself, but also a tool to gather information about what your audience thinks about you, so use it to your advantage and do not be afraid, or paranoid about it.

7. .com might just be all you really need – via @Joel_Hughes

Joel showed how much stuff can be done and achieved through a blog built on WordPress.com and that for a lot of purposes you don’t really need to host your own website using WordPress.org. I think the coolest and geekiest thing Joel showed was his “call to action” buttons made in wordpress.com. I never knew you could do that and I will have to check out his website to see how to do it, because it looks pretty awesome.

So, this are the 7 tips I took with me today and I hope you will find them useful too. If you haven’t attended one of the @WordpressWales events yet I strongly suggest you come to the next one. Keep an eye on their Twitter feeds and their website, so you will not miss out next time.

Anyone who insists technology is disempowering has probably not come across really young learners interacting with it. Today I was reminded about how intuitive, engaging and formative technologies like the iPad really are.

I want to call Nonna!

My 2 year old boy, Martino, felt like talking to Nonna (grandma in Italian). I say talking, but, although he can say quite a few words, he hasn’t learnt to say many sentences yet. What he has learnt to do, and very quickly, is to use an iPad. In fact, he’s so good at it that today he ran in the kitchen, took the iPad Mini and came back to the sofa looking pleased with himself. Then, he turned it on, swiped to access the apps, found FaceTime inside a folder and called my mum from the recent calls. When Matteo (my eldest) heard the ringing sound of FaceTime he asked Martino, if he was calling Nonna. “Sí, Sí!” answered Martino.

IMG_1666Needless to say that this unexpected call made my mum’s day, but what I’ve witnessed today, and many other times since Martino was one and a half, is something that made me think deeply about the power of technology.

Our learners are deeply engaged with technology, they grow surrounded by it and naturally embrace it as part of their learning. I believe it is essential we engage our students with technology to harness this enthusiasm our young people show for it. I heard of many primary and secondary schools that began to use iPads when they noticed their youngest learners kept touching the screen of PCs and laptops the first time they used them. iPads, smartphones and tablets are engaging and an integral part of many learners’ every day routines. They are drawn to them and naturally interact with such devices with great interest and proficiency, so using them in the classroom seems to me to be a logical way to engage children in their learning. This will make schooling more fun, but that should never be the driver for integrating technology in the classroom! iPads and other technologies open ways to redefine pedagogy and learning experiences. They empower learners and teachers, so that students become more independent and creators of knowledge, rather than simply consumers of knowledge. Let’s embrace technology for the right reasons and not thinking that the kit will solve all the teaching and learning challenges in our schools.

There are many ways to use technology creatively and innovatively to enrich our learning environments and much can be learnt from educational blogs such the CollaboratEd.org.uk Blog (@Collaborat_Ed), Neil Atkin’s Blog (@natkin), maybe this Blog you are reading and, one of my favourite, Gavin Smart’s Blog (@GavinSmart).

Yet another mind map to help you making sense of the Guide for Schools: Part 2 of the NSP (Phase 2). This map deals with the content of the NSP Toolkit aimed at supporting school in the implementation of the Literacy and Numeracy Framework (LNF) in Wales. You can use the HD image below as it is in presentations, or download the iMindMap version to edit it from this Biggerplate page, or just navigate through the map via this online viewer. Whatever you do with it, please acknowledge the source, Alessio Bernardelli (@asober). Let me know if you find this useful.

NSP Toolkit