An example of Lenz's Law

Today we finished up with Lenz’s law, and found the direction of current induced in rings of wire near changing magnetic fields.  We did a demonstration where an electromagnet was plugged into a walkman and then brought near the play head of a tape player.  We heard the walkman through the tape player (showing electromagnetic induction, and previewing the idea of a transformer).

We then used Lenz’s law to describe how alternating current is produced (AC), and showed how alternating current can be transformed using a transformer. We learned one transformer equation:

Vs/Vp = Ns/Np

which we used on the homework for the night.

HW:

• Read ch 25.2 (transformers)
• Do problems

Happy St. Patrick’s Day!

Recent earthquakes have made days shorter - according to Richard Gross, a geophysicist at Nasa’s Jet Propulsion Laboratory in this Guardian report.

Not enough to make you feel like time is running out – that’ll be the approaching exams and such…

But the earthquake in Chile has probably made a day a few microseconds (millionths of seconds) shorter… not much in the grade scheme of things – it’d take years (403 of them)  for the difference to even be a second!

Mr G

Having droned on about BBC radio (and politics) the other day, I come to today’s blog feeling the need to praise BBC television. A week or two ago the corporation announced that they would be slashing two digital radio stations in oder to concentrate on producing quality programmes for both radio and TV. Hopefully this might ensure that Radio 4 returns to the in-depth journalism upon which it founded its reputation. As far as the TV shows go, it appears that they’re already making good on their promisem as well as living up to the ideals of their former Director General, Lord Reith.

Lord Reith was made DG in 1927 and instilled into the corporation that their remit ought to be to produce programmes which educated, informed and entertained the listeners. Noble aims but, given that the corporation was, and still is, funded by the listeners in the form of their licence fees, it is the nearest thing to a public broadcaster we have in the 21st century.

Now there are times, mostly when I walk into the room when the girls are watching CBeebies (the BBC channel aimed at youngster viewers) when I wonder where the education and information element has gone. I grew up with kid’s programmes like Blue Peter and Newsround, which stiffly yet wholeheartedly supplemented my school education and attempted to broaden my awareness of the wider world. Thus being subjected to a puppet cactus which gargles not quite decipherable English and it’s current co-host, a barely pubescent and incoherently accented young Scotsman, makes me yearn for the days when presenters spoke in clipped Received Pronunciation and were capable of stringing actual sentences together.

However, while I may be extremely childlike (or childish) much of the time, I’m not a child so perhaps I ought not to expect kid’s programmes to appeal to me any more. Which is where ‘big people’s’ BBC is coming into its own at present. The soap opera ‘Eastenders‘, which celebrated its 25th anniversary a few weeks back, has apparently remembered that it built its reputation by constructing storylines around the social issues of the day. The acting is still mostly dreadful, the sets still rather flimsy but, by going back to the basics of illuminating the human stories which lie beneath the most outrageous of tabloid headlines, the programme is once more offering a small counterbalance to the soundbite culture that suffices for journalism in most newspapers nowadays. Well, that’s my excuse for watching a soap, anyway.

Far more informative, as well as being highly educational and entertaining, are the various wildlife programmes which the BBC has a grand tradition of producing. ‘Yellowstone’ and ‘How Earth Made Us‘ are two of the grander scale shows but even ‘Lambing Live‘, which spent five days focusing on sheep farming – one of Britain’s largest industries and one which still supplies over 80% of the lamb in our shops – was hughly watchable. Of course Mrs Planet and I were interested because we fostered little orphan Annie lamb last year. Made us both sort of hanker for another little lamb all over again, despite the mess and the lack of sleep and the heartache of having to give her away once she was weaned.

Two current series above all are the ones which have reminded me of Lord Reith’s remit. Last night saw the first of three programmes focusing on ‘Invisible Worlds’. Using high speed cameras the show explores phenomena that the naked eye cannot see. From the shock wave mechanicss caused by tons of dynamite being exploded to the sprites shot up into the stratosphere during lightning storms, the programme was absorbing (and made me wish I could afford cameras like that). If physics theory had been presented in such a manner when I was at school I might have actually been engrossed rather than scraping by when it came to exams. I’m sure we can all remember the Van Der Graaf Generator sticking our hair up but that seemed to be the only exciting item in five years of the curriculum at my school so most of the rest of it leaked out of my brain almost as soon as I left the classroom each week.

Which brings me to ‘Wonders of the Solar System’. Now I can’t even name the most basic of constellations, have no idea where the Pole Star is, and the most I know about the Moon is that it is not made from green cheese. Actually that’s not true, I do know how to tell whether the moon is waxing or waning simply by looking at the visible portions in the night sky – ‘If in the East, the moon shall be increased; if in the West, the moon is past its best.’ But after that I’m blank. Cue Professor Brian Cox, a particle physicist whose new five-part series explains the formation and structure of the solar system more accessibly than any scientific programme I’ve ever seen. I already want to go out and buy a telescope so that I can better acquaint myself with the planets and stars (might be waiting a while, given we’re not exactly loaded). I think it helps that Cox is a former popstar (he played keyboards for D:Ream, who had a No.1 single with ‘Things Can Only Get Better’), and the fact that he is clearly excited by pretty much everything he talks about doesn’t do his case any harm. He reminds me of one of those teachers at school who was an obvious geek yet somehow utterly cool too – the sort who swept you up into their mad delight and whose words come back to you decades later. Lord Reith might not approve of his regional accent but Cox is clearly living up to that Reithian remit: I was so enthralled by the second programme that my mouth was pretty much wide open in oafish astonishment throughout. At the risk of sounding like one of those Guardian-reading types who write in to the BBC’s ‘Points of View’ or ‘Feedback’ programmes, ‘More Please, BBC.’

Lee Smolin

Today we spoke with Lee Smolin, a theoretical physicist who’s written three books and done his share of interviews. We asked him to share his experiences with the media and give us some tips from the other side of the tape recorder.

Research!

One of the most annoying things for Smolin is when the interviewer obviously hasn’t done his homework.

“One thing that’s annoying on things like live interview shows and radio and television is when you realize the person is reading from a script that’s prepared by the staff, but they haven’t actually read your book or paper. Occasionally there are people, like  Dennis Overbye who does the morning show on the BBC, that are so skilled that (they) can wing it and get away with it. But mostly it’s really apparent that they don’t know and haven’t prepared or are going by a script,” he said.

Communication

Smolin makes a real effort to communicate clearly with journalists so he won’t be misunderstood.

“I feel like it’s part of the job, a very important part of the job of being a scientist is communicating with the public. I care about communicating clearly… I think the public is not to be pandered to, not to be talked down to. That is, a lot of the public follow science. You have to find a medium, but the idea that you have to treat them like children, I think it’s not true. “

Of course, communication is a two-way street. It requires careful explanations from the scientist, but the journalist also has to know how to listen.

“A journalist is not usually trained scientifically, so you try to explain clearly. They’re different than a member of the general public, they’ve talked to a lot of scientists, if they’re good, they know how to listen to a scientist and they know if they’re being snowed. I think it’s very important to have integrity, to tell the truth, to say the strong points and the weak points and not to exaggerate any of the direction because it’s not in the interest of telling the truth and good journalists can tell when they’re being snowed,” Smolin added.

Miscommunication and poor listening skills on the part of the journalist can lead to misinformation. Smolin says he’s been misquoted many times. He tries to maintain some control by asking to review his quotes before they’re printed.

“It’s often not granted, but I always ask for them to come back with permission to quote, and to give me a veto for quotes. I have been quoted out of context. You get to know who does it and who doesn’t,” he said.

Understanding

Smolin says it’s important for journalists to understand science and be aware of how the scientific community works. Because the information can be very complex, it’s tempting for reporters to use a formulaic writing style that isn’t always accurate.

For example, Smolin is frustrated with the way journalists have been reporting on climate change.

“There’s a principle in political reporting of balance, that is, you quote from both sides. But in the case of a story like climate change… there’s not really two equal sides. There’s 95 or 99 per cent of scientists who have come to a consensus about an issue, and then there’s a few people who disagree around the edges. And that’s always the case in science… Stories that attempt to follow the political formula for quoting both sides get it wrong and get it wrong in a dangerous way because they take a few malcontents and quote them equally. This takes judgement, this takes knowing the scientific community well, and it takes having a sense of what science is and how it works,” he said.

Tips for aspiring science reporters

“Preparation is very important.”

“Understand how science works, understand the complexities and don’t walk around with a cartoon of the scientific method in your head.”

“Read the really good ones. In North America, Dennis Overbye, search, read everything he’s written. He also has a sense of humour and a sense of  humanity, but he’s razor sharp in terms of getting the science right.”

Remembered a bit of my dream again this morning, but I forgot most of it already. I just remember that in it, Chase had sent me an email with like an interesting link to look at.  Wonder if it’s because I saw that video on that other breakup blog? Here it is:

Studied for physics theory until 5AM then slept until 11AM, but I don’t know how well the final went. After comparing with Karen, I think that I made a lot of mistakes, so I’m feeling frustrated. I hope that there is curve in the class, or else I might be seeing another B on my transcript this quarter. Horrible.

Karen mentioned Eric, since he’s driving her to the airport, and then she said that “they all” came to Tapex last night after studying at Tobi’s lab. ><  I wish she hadn’t told me, because it started me about the stupid person again.  I don’t want to care what he did, who he’s hanging out with, anything. Also David texted me about dropping me off at the airport, so we’ll leave around 7PM, and he mentioned that he has “plans” for that night.  All these things that make me remember and think and become upset/annoyed.

At least while at Tapex, we ran into Han, so we walked back together, talking about random unrelated things. That made me feel a bit better.I’m looking forward to semiformal! Hope that things will be resolved by then.

Today, studying MMW from 4PM to 730PM, with the goal of finishing my half of the terms and passages. Review session 8PM-9pM, then will try to finish MMW passages and then start the mechanisms and reactions for ochem.

I was impressed by how well you tackled Faraday’s Law, you really seemed to understand the homework. After going over the homework, we watched this motor video:

We then talked about how motors work, which direction they will turn (using the third right hand rule) and how we could increase the angular velocity of the motor by increasing the voltage.

This led us into different discussions for each class, but each discussion led us to discuss Lenz’s Law :

Lenz’s Law is the observation that the current induced in a circuit flows in a direction that produces a magnetic field opposing the change in flux that produces the current.

Along with some of the demonstrations that we did in class, you can see more demos on this Lenz’s Law video.