Lerderderg 15hr Rogaine

A few weeks ago, Cecilia and I were on our way home from canoe polo at the campus pool when we bumped into Dan.  I didn’t know Dan, but Cecilia did – presumably because they’re both exchange students from the states.  During the course of our brief conversation, Dan said he was keen on the idea of Rogaining.  I had been out of contact with my rogaine partners from last year, so I did my best to etch Dan’s contact details on a banana I had in my pocket with my keys (in lieu of pen and paper).  It turned out that he gave me the wrong phone number, but we set the record straight with facebook.

I sorted out entry and payment for our team of two, Dan hired out camping gear and whatnot from the bushwalking club and found us a ride to the event.  Unfortunately our driver did her ankle at a netball game the Thursday before the rogaine and pulled out, so I found another ride at the last minute.

Greg met us at 8 on Saturday morning, we made it out to the hash house by about 10:30 after a wrong turn, a stop to pick up Greg’s partner Mick, and a coffee break at a fantastic small-town bakery along the way.  Dan and I pitched the tent, checked in, collected the map and made a flight plan.  We left at noon – Dan was the pack horse and I was the navigator.  Not how it’s usually done, but this arrangement turned out to be quite effective.

The first couple of checkpoints were quite crowded, as is to be expected at the start of an event.  At one of the early checkpoints, two older women arrived as we were writing our particulars on the marker.  The lady in front, while explicitly stating that she didn’t mean to be pedantic, pretty much accused us of trying to sabbotage their game by taking too long at the checkpoint.  Bitch!  I mean, waiting 15 seconds for us to finish isn’t going to make much of a difference over a 15 (or 24) hour event.  We were determined to get more points than the older women.

It was pretty smooth sailing all afternoon with few navigational errors.  We occasionally referred to features on the map more nerdily as things like ‘local maxima’, ‘local minima’ or ‘places with a maximised directional derivative’.  Steady progress was made in a southerly direction, away from the hash house to where all the high-scoring checkpoints were.  We met some older bush walkers from Tasmania at around 4:00, and then again before dark.  Nice to talk to, but they’d bite your ear off when given a chance.

We got lost on dusk (Mick told me later that’s what usually happens) – turned off the road too early and went up the wrong hill.  Oops.  By the time we went back down that hill and up the right one to the checkpoint, it was time to put our headlights on.  It was the first time I had done night navigation, and to my suprise we were spot-on most of the time.  We made it to a water drop at about 8:30 to find not only the usual supplies of water and fruit, but sandwiches too!  A fine selection of jam, vegemite and peanut butter we had to choose from.  Dan ate about half a dozen, but then again he’d been carring the backpack for the two of us from the start.

Tiredness made for some delusional conversation for the hour or two before we got back to the hash house at 10:30.  Soup!  Stew!  Cous cous!  Chocolate custard and stewed pears!  The hash house always has a top-noch meal for returning rogainers.  The catering team ran their first-class volunteer operation from a farm shed, all night long.  In addition, there were a number of camp fires to choose to warm ourselves with; the flames and a warm meal seemed to facilitate communication as tired rogainers swapped stories from the day.

Woke up around 7:00 the next morning, had a quick bite to eat left within half an hour.  I found the early moring walk a relaxing experience, perhaps even magical; the air was crisp and sweet as the dirt road – clearly less traveled than it once was – took us on a tour of crumbling houses, rusting machinery and vintage trucks with vines poking out of the cabin.  The odd pile of hay bales indicated that someone still used the land, but whoever they were they were nowhere to be seen.

This tree managed to catch my attention, for it had clearly suffered a traumatic experience earlier on in life.  Nevertheless, it manages to maintain a carefully balanced perfection, smooth, seamless, stable.  Do trees know about center of mass?

We made it back to the hash hous a couple of minutes before noon.  I experienced the most amazing cheese toastie ever.  Monash actually won the university competition, so we (along with two other teams) were recognised during the presentation and awarded our choice of chocolate bar.  I was quite pleased with our team score of 1420 points (unofficially, as one checkpoint wasn’t counted for some reason).  Packed up camp and headed back home.

We stopped at the same bakery, this time for a vanilla slice.  A top-notch vanilla slice is characterised by a crispy pastry and light custard filling; where I live most bakeries are run by Chinese bakers who have little appreciation for the humble vanilla slice.  I am pleased to report that this particular slice was top-notch.

I was sore and stiff for two or three days afterwards, but the weekend away was completely worth it.

Apparently there are rogaining events run in Europe, Japan, North America and North Queensland, so there’s really no excuse not to try it out.

Ants in my Plants!

I don’t like having ants in my plant boxes.  So I wrote the ants a message and drew a line in chalk to show them where they weren’t allowed.  To my surprise, the ants honoured my request and stayed away from my herbs.  Perhaps this is an indication that the human being and ants can coexist peacefully.

I became distracted in a lecture today.  What would happen if you squared an imaginary friend?  What if this lecture theatre were filled to the top with bean bags?  If it were filled with small styrofoam balls, would everyone choke?

The Kitchen on 10th

When I walk into the kitchen around 6:40, Jessi is busy ripping the gills out of a fish head as his female accomplice prepares to make it into a soup.  I boil the kettle and soak my dried bean curd and fungus.

I return at around 7:30 to see that Kane and Ben have invited some friends up from the lower floors to cook.  There are about six people and four or five dishes.  Tonight we have sweet potato risotto, chicken and mushrooms, an omlette and miscellaneous stir fry.  ‘Cafe Malaysia’, as I call it, happens several nights a week.

Lee Kum Kee, Yeo’s, Ayam… the Malaysians are still amazed to see that all the brands from home are available for purchase here in Australia.  I inform them that these all cooking lables are in fact Australian, exported en masse throughout the pacific rim.  They stare at me in disbelief for a few seconds (‘huh?’) before realising that I’m kidding.  I’m intrigued at my own choice of brands: Superior Quality shiitake mushrooms, Cock Brand bean curd and Goldfish Brand cloud ear fungus.  One of the few redeeming qualities of Clayton is that it has the Hong Kong shop – also a reliable source for staples such as Pocky.

I start to prepare my meal (braised pork and taro) as the Malaysians enter the eat phase of their well-established cook-eat-repeat cycle.  They marvel at my resourcefulness in acquiring the dried ingredients, and eventually I offer them some cloud ears (which had expanded in the hot water more than I had expected) for some kind of mushroom omelette.

Before long, the Malaysians are back at the cooktop, bringing the Stove Availability Index (SAI) down to 1, ie. one free hot plate.  My neighbour Pear wafts in and fishes out her wok.  She seems oblivious to the chaos around her as she prepares a simple cucumber, mushroom and egg stir fry.  Pear told me the other day that it’s not her real name that she uses, but rather a nickname from her aunty.  She’s got a twin sister called Peach.  Peach and Pear – now that would have been cute.

By now it’s about 8:30 and the Malaysians are just about done, as is my dinner.  Pear’s gone, but then Bruno and Marco (medical interns from Italy) come in to do roast spuds.  The SAI plummets to 0.  I take my pot off the stove and dish myself some rice.  Now for the moment of truth.  A skype call with Denise half way through the evening had me anxious at leaving so much star anise in my pot, for it’s supposed to have a strong flavour.  Oops.  Not to worry, it tasted alright anyway.  I’d give it 6 out of 10, but I will make the observation that things often taste better when somebody else cooks them.

I offer ‘Ding Dang’ Dong, the Chinese girl on my floor, some of my dinner in return for the beef stew she offered me a few weeks ago.  She was impressed, or at least extremely polite.  “I can’t believe a guy cooked this”, she tells me.  Thanks Ding Dong, I’ll take that as the compliment you intended it to be.

Easter Break

I spent the first few days getting some work done so I could do nothing for the rest of the week.  Met up with David and Alita at an outer-suburban train station and went straight up to see Karl and Gladys.  David and Karl are brothers; I’m their second nephew.

We stopped at a small town – Yea, I think it was – and took a brief survey of the lunchtime dining options available.  Takeaway.  Four bakeries.  Pizza.  Small-town Chinese takeaway.  Up-market beer garden.  Quaint rustic cafe.  We really couldn’t decide, but eventually it all came down to David’s desire to sample the local pie scene.  We chose the cafe with the most customers over the cafe with the Best Pie Award for three years straight – because the more people there are the better the shop must be.  Supposedly.  David’s verdict?  Not the best he’d had, but respectable nonetheless.

The Yea offerings only served to remind me of the shocking pie experience on campus: a choice of four refrigerated varieties, microwaved on demand to a steaming, soggy mess that remains too hot to eat for over 10 minutes – and falls to bits thereafter.  After the Yea episode, I have decided that never again will I indulge in what Monash has on offer.  I didn’t intend to write a comparative review of pies, nor a whinge about Monash Clayton’s uninspiring campus atmosphere, so back to the story.

Karl & Gladys’ place was on the top of a hill, surrounded with cow paddocks and eucalyptus forest, the mountains in the distance not yet capped with snow.  The air was crisp and clear, in contrast Gladys’ sharp, warm cooking.  I can’t remember meat-and-three-veg ever being this good.  Gladys informed me that the bull we were eating was called George Bush, for his eyes looked just like those of a past American president.  Every day on dusk, David and Karl would make a trip to the ‘bottle-o’ (actually a well-stocked tin shed at the bottom of the hill) to select the night’s wine list.  There was a dog called Blogs, and a dozen brown hens in a multi-million dollar security complex (to keep foxes out) and some lovely black cows.  Home?

Alita and I spent one lazy morning walking to Power’s Lookout so we could check for troopers.  This particular lookout was named after Harry Power, mentor in bushranging to Ned Kelly, who took advantage of the site’s well maintained steel stairs and lookout platforms to watch for adversaries pursuing him up the valley.  Additionally, Power decided from time to time to use the lookout site as a base camp of sorts.  I’m sure this was because the undercover fireplace, numerous camp oven sites and composting toilets provided all the mod cons a man on the run could ever dream of.

Another quarter day adventure was spent trying to locate a waterfall on the edge of the property.  Alita and I thought we found it, but as there was no water flowing at the time, it was a bit hard to tell.  What do you call a waterfall with no water?  Our suspicions were confirmed a few days later when Karl took us back to the same spot and said it was indeed the waterfall.

The house features a wood fired heating system, so every autumn Karl stockpiles a shed full of dry wood to stay warm over the cold, wet months to come.  There was also bracken fern to slash in the cow paddocks.  I am happy to report that I remembered how to cook crepes, much to the satisfaction of everyone else at the dinner table.  We ate them with Cointreau-soaked strawberries and icecream, and rum and brown sugar (something I hadn’t tried before).

The train ride back to Melbourne reminded me of how nice rail travel can be, for nice is something the suburban rail experience in Melbourne is not.  Soon after we left, one of the hosties approached the lady in front of me.  “Nah, sorry luv we’re runnin a bit behind schedule so unfortunately we can’t stop to let you have a ciggie break orright?  Yeah, sorry but we jus’ can’t do it yunno.”  I like the idea that the train could have make an unscheduled stop to let its passengers smoke their tobacco, it was an indicator of how relaxed the journey was.

Later on, a little girl was dragged up to the front of the carriage by her mother for a couple of stern words.  Evidently the girl was guilty of not putting on her sock, and continued to protest until tears came out.  At that point, another girl not much older than the first decided to go up and ask the young demonstrator if she’d like some gummy snakes.  The mother quickly replied that her daughter was content, thank you anyway.

What a great week away.

Matrix Encryption

A few years ago I wasted a lot of time writing a Javascript implementation of matrix encryption.  Now one of my maths assignments has a section about decrypting an encoded string… Russian spies… dead letter drops… yada yada.  I’ll be using my trusty Javascript implementation to blow the question over in a minute as opposed to 30.  I’m posting it here in case whoever marks my assignment wants to see it.

Unfortunately, WordPress.com doesn’t allow .zip uploads, so I’ve been a bit sneaky.  One quick and dirty hack exploits the fact that zip files are read from the end first, and JPEG files from the beginning.  So if you were to append a zip file to the end of a JPEG image, you could use the resultant file as either – depending on which file extension you give it, or which program you open it with.  Under Linux/Mac/*BSD, you can do such an appending operation with cat LoveLetter.zip >> Image.jpg .  Read up about Steganography on Wikipedia if you find this intriguing.

I’ve taken advantage of this highly unsophisticated technique to make available to you, dear reader, a copy of the encryption program.  Unfortunately what I’m writing also makes me sound like a big-headded twit.  So without further ado, here are the instructions:

1. Save the picture of boy painting flowers
2. Rename it so it ends with .zip
3. Use your favourite unzip program to extract the contents.

Matrix encryption of the type I’ve used is very weak, but evidently popular in maths education.  I’m sure anybody with a computer could crack your love letter open with brute-force in a matter of minutes.  The only real-world application that comes to mind for this algorithm is to allow grade 10 girls to swap notes in their English class.

The painting is by Banksy, who has many other cool works to his name.  You can search for photos of his work on Flickr, where I nicked this one from.

Credit Crisis: Formula and Visual

Just a pair of top quality links I found this morning on Slashdot.

First, an article about the formula which pretty much single-handedly brought about today’s financial despair.  Allow me to summarise:  Evidence suggests that the quant who developed it knew the limitations of his model, but financial managers everywhere were drawn in by the simple treatment of complicated behaviour (correlation between two probabilities).  This formula ended up becoming so popular that by the time things happened which it didn’t predict, everyone was screwed.  Remember, it’s the managers who are responsible for the quagmire here because they went ahead and used this particular model against the advice of people in the know.  Moral of the story?  Study more maths.  Article here.

Second, a video posted in the ensuing discussion: The Crisis of Credit, Visualised.  Short and simple.  Watch it.

End of summer and back to school

Well it looks like three months of summer vacation has finally come to an end.  Long as it may seem, I still could have used an extra month or two.  Nevertheless, I think I made good use of the time I had.  Mango farm stints are always good for money and meeting crazy people.  I read some books, and started to read some others.  Some ideas were fleshed out, namely the vegetable patch and a website called Supply Project (not done yet!).  I managed to fit in a slight amount of adventuretainmnet on top of that and even caught up with my local acquaintances.  I did not, however, manage to make it to Temptations Cafe to see Emma for my annual dose of gossip.  But that’s not something I really regret.

I wasn’t happy how the weather turned good just before I left for uni, but better late than never.  Kimberley felt the same, so we returned one last time to the infamous Churchill Creek.  We spent a good deal of time on a Japanese Walk (ie, with camera in hand) because the cities we study in lack natural delights such as our creek.  I wish I could photograph smells, because the rainforest smells so nice.  In late November I made a promise to photographically document the natural beauty of where I’m from, but unfortunately all I have to offer him at the moment are three mediocre pictures.  As always, better photo opportunities were discovered without a camera at hand.  Igrar, perhaps it would be easier if you just visited me and took the photos yourself.

I arrived back in Melbourne to be part of the residential O-week team.  I can’t think of anything exciting that happened during the week, however I did have a couple of episodes with some female team members who had a heightened sense of self importance.  Although she doesn’t know it, one particular individual elevated herself the rank of Stupid Bitch.  People I admit to such an exclusive category no longer bother me with their words or actions, for periods of more than two minutes.  However, I still maintain an outward sense of civility politeness towards them.  This year, I am determined to identify Stupid Bitches where possible so as to reduce the amount of stress caused by them.

In terms of accommodation, I’ve leveled-up to 10th floor.  This affords me a view of the city in the distance, all the more appreciated as the campus and its industrial/suburban surroundings do little to inspire or motivate me.  I’ve also sourced some plants to put on my window sill, they’re probably the greenest within 20 kilometres.  After speaking with a like-minded American, I’ve decided to grow some “erbs” and she’s decided to grow some “herbs”.  We’re calling this an inter-cultural experience.

I asked one floor mate if she was from China or Hong Kong.  She snapped back with “Hong Kong belongs to China!  Why do people always ask as if Hong Kong is separate?”.  It seems that Chinese people can be sensitive when it comes to territory, especially when you also consider tensions with places like Taiwan and Tibet.  As far as I’m concerned, even though Hong Kong is technically a part of China, people from Hong Kong will readily identify as such, rather than as Chinese.  I don’t think the same people identified as British back before the handover, either.  What it all boils down to identity, and Hong Kong is both unique and well known case.

Languages spoken by the residents of 10th floor include Greek, Italian, French, German, Cantonese, Mandarin, Malay and Tamil – not to mention English.  Monolinguals are by far the minority.  Within walking distance I can find speakers of Persian, Hindi, Russian, Japanese, Urdu, Korean and Indonesian – just off the top of my head.  Arising from such rampant multi-lingualism would be a huge variation in thought, which truly amazes me.  My neighbour’s name is Pear, which I suspect is a direct translation from her native language.  Pear gets easily confused.

Keeping me busy this semester will be units entitled Linear Algebra, Real Analysis, Quantum Physics and Symbolic Logic.  I’ve half a mind to blog about what I study – not to show you how much of a nerd I am (for that should already be apparent), but rather to help me learn, to answer the question ‘so what do you actually study?’, and to spread ideas.  I’ve mentioned previously that because reading a blog is a purely opt-in affair, I am at liberty to write about whatever I want.  Talking about maths and physics at the local pub would promptly result in one being labled a big-headed twit, however the blog is the perfect venue to stage such discussions.  If it doesn’t interest you, don’t read it – but it’s OK to get intellectual.  Sometimes.

Ubuntu 8.10 on Gengies’ Mini 9

OK, so the other week my grandparents were experiencing computer delinquency with their desktop tower.  I went down to investigate, and determined that the problem was in the hardware.   Luckily Goong Goong realised that given his previous grievances with the same computer, it would be worth neither the trouble nor the cost to fix.  Luckily he talked himself into buying a new machine, for even though they needed it, I wasn’t prepared to sink to the depths of Computer Salesperson that day.

We hit the shops.  I had a netbook in mind (low cost, highly portable), but was disappointed to see that nobody stocked any with Linux.  Every sales rep told me that Australian buyers wanted a “familiar” computing environment, but from our experience I would cite a lack of retail choice as an explanation for such low consumer demand.  Nobody’s going to want something they don’t know about and can’t see on the shelf!  Talk about a coordinated wimp out by Australia’s technology marketing departments.

In the end, we settled on a Dell Mini 9 – complete with Microsoft tax, which means to say that we had to pay for something that we didn’t want and won’t use.  Windows XP.  You see, as a responsible grandchild there is absolutely no way I am going to allow my grandparents to continue to be exposed to the horror that is computing with Windows.  After opening the box, I wasted no time in exorcising said operating system and furnishing the new computer with Ubuntu 8.10.  If you don’t know what Ubuntu is, let me suffice to say that it is a free, high-quality alternative to Microsoft Windows or Mac OS (light years ahead of the former), and direct you to the the definitive Wikipedia article.

The whole point of this post is not to chronicle, critique or complain, but to save some notes for my future reference.  I’ll waste no more time in doing just that.

1. Use Ubuntu’s ‘Make USB Startup Disk’ utility to write the standard desktop iso to a nerdstick, install on the mini
2. Update package lists and install updates
3. Sound: add options snd-hda-intel model=dell to /etc/modprobe.d/alsa.base
4. Skype: requires libqt4-core and libqt4-gui.  Install skype-common and skype from Medibuntu
5. Printer (Pixma MP 810): requires alien.  Get cnijfilter-common 2.60 from Canon Europe
6. Scanner: keep an eye on Gnome Scan
7. Applications: openssh-server, banshee, gstreamer plugins (incl. mp3 ripper), flash
8. Configuration: Firefox bookmarks, F-spot, Banshee.  Skype instructions here.

Lighthouse Mountain

Many years ago – 400 million to be precise – much of what is now Far North Queensland was below sea level.  Places such as Chillagoe, now about 200km inland, were surrounded with coral reef.  I imagine that animals such as fish, whales, turtles and nautilus floated above the mango paddock where I worked, throughout down town Mareeba and most certainly Mossman.  To stop them bumping into rocks, the prehistoric creatures were in desperate need of a navigational aid.  This prompted them to build a lighthouse.

Today, the remnants of this mythical navigational structure sit on top of the aptly named Lighthouse Mountain between Mt Molloy and Mt Carbine.  The mountain has been scaled by many people in the past, including one young girl who would eventually give birth to a child who would father somebody who on Valentine’s day 2009 (last Saturday of the summer vacation) would see the mountain as an opportunity for adventuretainment with a couple of mates.

Being the middle of the wet season, it is difficult to plan more than a few days in advance.  Lighthouse Mountain presented a somewhat more rain-proof expedition than other trails in the area.  Plans materialised from meta-plans at the last minute, which is really the best way to do things anyway.

I must admit experiencing a bout of insomnia the night before.  Surely the effects of an iced coffee don’t last for five hours, right?  Even so, never again will I drink a coffee after five in the afternoon.  Perhaps it was a sense of excitement at finally making it outdoors (after weeks of rain) that kept me up.  The Insomnia Support Chatline provided some assistance, for which I thank her, but I think I may have rudely interrupted her in the middle of trying to get some honest work done in a different time zone.

People often complain about how the English language lacks a sense of elegance and style.  I suspect this reputation comes from English’s ability to adulterate innocent, harmless foreign words into monstrocities like ‘rendezvousing’.  Perhaps the blame also lies in how easily English allows misinformed bloggers such as myself to use such vile creations in sentences like: “However, I woke up the next morning with ample time to prepare before rendezvousing with Cowan, Matt and Alex”.

The first venture out into unfamiliar territory often fails to  an efficient route.  Such was the case today: we spent the better part of the first two hours following Luster Creek and making it to the base of the mountain.  Here’s the route we took. Along the way we found a flask of stale tea and a massive stick insect.  The bright green stick insect must have been close to 30cm long, but it seems that Cowan lost the photos he took of it.

View from the lighthouse (click for full sized image). I do admit that it's a bit dark. It's really easy to stitch panoramas together with the Gimp and Pandora plugin.

After a couple of breaks along the way, we eventually made it to the lighthouse just after lunch.  While the view from the top of the rock would have been amazing (and Cowan reports that people have climbed it, only to get stuck up there), we were disappointed to discover that this lighthouse lacked a staircase.  Not surprising, really, when you consider the fact that the lighthouse predates the advent of the staircase by 399 million years.  Did you know that the word for ‘stairs’ is the same in Japanese as it is in Korean?

We made it back along a power supply route which joined on to the main road – in hindsight this would have been a quicker way to get straight to the lighthouse, but who’s worried about speed on a Saturday morning anyway?  I’d estimate our total mileage for the day would have been about 16km, more than half spent travelling cross-country (ie, without a trail).  We made a brief stop at Churchill creek on the way back – unusually cool and clear today after the recent rains.

It’s unfortunate that most of our peers in the area spend a great deal of time drinking.  Alcohol, whose many applications include enabling the socialisation of people who are uncomfortable with themselves (or just plain awkward), is not a prerequisite for having a blast.  Sure, parties are great for catching up with mates and all, but it’s important to know that you can have a good time while staying sober as a noodle.  I find that the satisfaction from a good day spent outdoors is usually longer lasting to boot.

For those who are interested in planning future expeditions, topographic maps can be bought in Cairns from Absell’s Map Shop or Cairns Navigation Centre.  Google Earth (or Maps) is also a useful resource, providing recent satellite imagery.

Cosmospostman’s Introduction to Energy 3

Energy Usage: Power

Almost as an afterthought, I’ve decided to add a short section here to discuss energy usage.  According to the definitive article on Wikipedia, a person climbing up a flight of stairs uses energy (or ‘does work’) at a rate of 200 joules per second.  Like ‘Work’, the word ‘Power’ has a technical meaning: the rate at which energy is transferred (lost or gained).  The unit of Power is the Watt, and to say that something uses one watt of power means that it uses one joule of energy per second.  The person climbing the stars draws 200 watts of power from their biological (chemical) energy reserves.

How much energy would our staircase adventurer burn if they climbed a very large staircase for one hour?  There are 3600 seconds in an hour, so she would burn a total of 3600*200 = 720 000 joules.  That’s 720 kilojoules, or according to Google, 172kcal.  This amount of energy could also be expressed as ’200 watt-hours’, which means ‘energy used by drawing 200 watts for one hour (or one watt for 200 hours, or anything in between)’.

Now comes the bit about your electricity bill: what does it mean to say that you used 1200 kilowatt hours over the last month?  It means that if you were to use your entire month’s worth of energy in just one hour, you would use energy at a rate of 1200 kilowatts, ie. 1200 kilojoules per second.  I think it’s slightly confusing to talk about energy in terms of ‘hours’.  It’s a bit like reading a credit card statement saying that you spent 5810 ‘dollar-hours’ (ie, $5810 dollars over an hour, or $1 per hour for 5810 hours).  Fortunately, kilowatt hours and joules measure the same thing (energy), so direct conversion is possible: 1 kilowatt hour is 3 600 kilojoules.  Nothing to do with time at all.

Examples

One

The Slippery Slope

Back to the unfortunate saga of our moose.  Suppose he has been dragged to one side of a steep valley by the hunter.  The hill is covered with very slippery ice, and the opposite side of the hill is only half as high.  The hunter has had enough of pulling the moose around all day, and decides to dispose of the carcass.  [1] At the top of the hill, the moose has nothing but gravitational potential energy.  Let’s ignore the chemical energy stored inside the moose (it won’t change), and regard any other types of energy as negligible.  The hunter gives the moose a very slight push, sending it sliding down the hill.  [2] Half way down the hill, moosie’s gravitational potential has been halved.  Most of it has been converted to kinetic energy, but some of it has been lost to the Work done to friction and drag.  [3] At the bottom of the hill, all of the gravitational potential has now been converted to kinetic energy.  A little more has been lost to friction and drag. [4] Having slid up to the opposite side of the valley (at half the height of the starting position), the moose has regained half of its initial gravitational potential energy.  It still has some kinetic energy left over, but even more energy has been used resisting friction and drag.

Two

The Romantic Cruise

Harriet and Kenichi decided to go on a romantic weekend sailing cruise.  [1] Initially, their yacht is at rest (no energy).  [2] A gust of wind blows against their ship’s sails, doing work on the ship (giving it kinetic energy).  [3] The wind stops, and by now the yacht is experiencing a significant drag force as it glides through the water.  It is losing energy.  [4]  The Work due to drag brings the yacht to a stop, and returns it to a state of ‘no energy’.  Of course, saying that the yacht has no energy is a bit of a lie in that there will be energy stored in Kenichi’s digital camera batteries, Harriet’s battery powered hair straightener and the couple’s romantic dinner for two.  However, those energy sources are ignored as they have no influence on the broad-scale sailing experience.

Recapitulation

Opening this one-way discussion was an explanation that boiled down to energy giving things the ability to push other things.  In this discussion, the words ‘push’ and ‘pull’ were synonymous.  Push is what initiates movement, and also what brings things to a halt.  Whenever energy is mentioned – however abstractly – it should be possible to identify how this concept of push is involved.  As a simple example, oil reserves store energy which will eventually allow the push required to move cars, buses, trains, ships and aeroplanes.  An ‘energy crisis’ is a big deal because if you can’t push and move things around your country (like food), things pretty much come to a standstill.

In the second round, different types of energy were identified.  Each type of energy gives an object the ability to push, and each type arises from different circumstances regarding phenomena like gravity, motion, magnetism and electricity.  One special case was that of chemical energy, in that it arises not from an object’s situation, but rather from the configuration of electrons.  The idea is that to make use of chemical energy, a chemical reaction takes place that liberates energy as push. With this as the exception, a point was made that objects ‘with’ energy are in a physical sense the same thing as they are ‘without’ energy – where as a person with a potato is physically different to a person without a potato.

The types of energy can be generalised into two categories: kinetic (moving) and potential (not moving).  Potential energy is real, but it can be hard to identify.  Energy is almost always an exercise in perspective and relativity, because energy ‘yardsticks’ are hard to come by.

Work, here a technical term, is energy as it is transferred between systems.  To transfer energy (“do work”), you need to push an object, and it has to move through a distance.  Just pushing won’t transfer energy: a helicopter parked on top of a skyscraper loses no energy, even as it continues to push down on the building.  Only if it were to move, then its energy would change.  Work is mathematically defined as the product of force and distance, and then we considered cases where the force applied was not in the same direction as movement.  This introduced some mathematical tools like vectors, the dot product and the line integral.

Friction and Drag are two forces that can be experienced when something moves.  Friction comes from the continual formation and breakage of molecular bonds, and Drag is due to you running into tiny particles of fluid as you move.  I didn’t explicitly point out that these forces, when experienced as an object moves through a distance, constitute Work.  Thus energy can be lost as a moving object does Work against friction and/or drag.

Power, another technical term, is how fast energy is transferred.  It is measured in Watts (joules per second).  Kilowatt-hours, the units of energy as seen on electricity bills everywhere, are directly convertible to Joules.  The kilowatt-hour, however, is a large amount of energy of magnitude suited to measuring electricity consumption.

The End

Well, I think that’s enough for now.  Please let me know if I’ve left you in a state of confusion, dear reader.  What’s been discussed represents a Classical view of energy – in other words, energy as experienced on scales greater than that of the atom but less than that of the galaxy.  Modern physics shows that things behave differently on very small and very large scales, and as such has developed concepts such as quantisation of energy and mass-energy equivalence.  Un-be-liev-able!  So when you think about it, the only thing that ends here is Cosmospostman’s Introduction to Energy.