Playing with fire

candle

A candle on earth

I remember making candles when I was a kid. We filled empty food cans with paraffin wax – the stuff that comes as a opaque block about the size of a deck of cards. The cans were then put into a bath of boiling water until all the wax melted. A few crayon stubs were added to each can, creating an array of colours. I tied a thick piece of cotton string, destined to be the wick, around a pencil for easy dipping.

Next, dipping (the messy part) could begin. With each dip another layer of wax clung to what was already there, increasing the diameter of the candle-to-be. I rotated through the colours, creating what must have been gaudy candles. When the candle was thick enough to stand on its own, the fun part began: we could light them.

A flaming match held to the exposed end of the wick has enough heat to vaporize wax within the wick and react with the oxygen in the air. Within moments a teardrop-shaped yellow flame flickers to life. The heat from the candle’s flame melts the wax, and the melted wax is drawn up by the wick, sustaining the flame. At its hottest, a candle’s flame can reach 1400 degrees Celsius.

Heat vaporizes the wax creating a gaseous cloud where combustion takes place. Combustion is a series of chemical reactions converting molecules into new combinations – an inefficient process resulting in heat and light. Light, along with its cousin heat, signify the release of excess energy.

Compared to an incandescent light bulb, a candle produces 100 time less light, which is probably why candles are now mostly used to set moods, conduct rituals and provide light in power outages. I don’t often light candles, after all they are one of the leading causes of residential fires and they put soot and chemicals into the air I breathe. But, when I do have a reason to light a candle, I enjoy watching the flickering flame – I find something about it quite mesmerizing.

In my mundane earth existence, when I light a candle the hot gases formed are less dense than the air around them, and so they rise in a process of natural convection into the familiar teardrop shape. This natural convection hinders complete combustion, so soot forms which makes the flame yellow.

Out in my funky futuristic (imaginary) spaceship, where there would be no gravity, natural convection wouldn’t occur, and I would get a perfectly spherical flame. And, the flame would require ventilation or it would smother itself as its temperature would be evenly distributed. (here’s a good, but slightly inaccurate video) On the plus side, the combustion would be complete – so soot would not form. The flame would be bluer and more efficient.

Another effect of gravity on a candle’s flame is the flickering. The frequency squared of a flame’s flickering is proportional to the force of gravity over the diameter of the candle. Meaning that a candle with a smaller diameter would flicker at a faster rate than one with a larger diameter. So a candle on another planet (with different gravity) would flicker at a different rate than the same candle on earth.

A candle on my spaceship wouldn’t flicker at all (I would have to be mesmerized by its pretty spherical blueness instead).

note – this post was originally published back in May 2010 (here)

another note – I downloaded the image from here

Some tidbits

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Black amaranth growing in a random place.

Here are some tidbits of science-y garden bits I’ve come across in the last little while.

Blue Food
I grow blueberries and blackberries. My brassicas all have a nice blue-ish tint. Last year I grew blue tomatoes (not tasty enough to bother growing again) and this year I’m trying to grow blue popcorn. I have black amaranth from last year volunteering itself everywhere, which I’d argue fits into the same colour category as those above – which is really more purple than blue. So, Why are so few foods blue?

Along the same vein of blue, I stumbled across this berry eons ago – too bad it isn’t edible (it sure is pretty).

Space Grass
We’ve been actively converting grass to vegetable garden here. This spring, we doubled my veggie growing space by taking over most of the front lawn (the area in front of the food forest). It has the most sunlight of anywhere on my lot, so I’ve filled the space with beans, corn, amaranth, sunflowers and brassicas. What I don’t want is grass, so I was surprised to read about astronauts growing grass on the space station. Why not more food? Lettuce has been grown successfully up there. Or more flowers? There has already been zinnias in space.

Hot Peppers
One of the podcasts I listen to recently had an interview with one of my favourite authors – Mary Roach. The interview was about her most recent book (Grunt) which came out earlier this month, and I ordered. The book is about the science behind keeping soldiers alive, I’m hoping to start reading my copy this weekend. It turns out she was inspired to write Grunt after a research trip to study the science behind hot peppers. Here’s the article.

Although, I have no plans to weaponize my hot peppers, my plants are growing big and healthy. Hopefully I’ll get a bumper crop to turn into hot sauces.

Space salad

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A red romain from my garden, which is safe within planet earth’s gravity

Sitting out on the deck last night looking for meteorites, we spotted the space station passing over head. What I didn’t know at the time, as the astronauts passed over my garden they might have been tending their own garden. Two of my favorite things are growing vegetables and space exploration – normally worlds that only collide in science fiction, but now for the first official time vegetables have been grown then eaten on the space station.

They dined on a salad made from a red romain lettuce called ‘Outredgeous’ one of the lettuces I grow –  the big difference is I don’t have to worry about my soil floating away and no one is telling me to clean the leaves with disinfectant wipes.

To deal with the soil, or in this case growing medium, floating away issue and other space complexities, ‘pillows’ have been designed to house each individual plant which is put under LED lights emitting optimal growing wavelengths in the ‘Veggie’ plant growing system. The first harvest was shipped back to earth to test if it was safe to eat. For round 2 the lettuce was given 33 days to mature before being converted to salad (some was saved for further earth-based testing).

I’m curious what’s next up to be grown on the space station.

 

Urban Nature

diversity in the garden

Why should you cultivate dandelions in sidewalk cracks, spiders in the attic and mushrooms in lawns…

Now that spring has fully arrived, I’m spending time weeding my garden. Volunteer plants have sprung up everywhere, like, well, weeds. I’m not pulling everything out – much to the annoyance of my neighbor who claims my few dandelions are an eyesore even though millions are in the park across the street.

Even in an urban environment (like where I live), we’re still part of nature. Urban living doesn’t have to mean surrounding ourselves with a concrete jungle; we can still make room for diversity in nature. Even the dandelion that takes root in a tiny crack in the pavement and the moss that grows on your roof counts as diversity.

Diversity is important because it adds a complexity that makes an ecosystem stable. A single change that destroys one species is not a big deal if many species fill that niche, but a very big deal if it was the only species. For this reason, any ecosystem with only a few species is vulnerable. Consider a lawn containing a single species of grass – soon weeds will move in or nutrients will be used up, forcing the owner to take drastic action like applying herbicides or fancy synthetic fertilizers. Or, consider diversity in relation to our food crops: using a single variety can result in crop failures and no back-up to turn to. A sad example is the potato famine that occurred in Ireland between 1845-1852 (from wikipedia article here). Even though there are many varieties of potatoes on this planet, the Irish only planted a select few species and blight wiped them out – bad, bad news.

A diverse ecosystem, in contrast, acts to buffer the effects of change. No one goes out into an old growth forest and sprays the dandelions (although, exotic plants can still invade). My garden, which I pack full off as many different crops into my tiny yard as I can, will always produce me something.

Taken as a whole, the Earth is an example of a diverse ecosystem and can be considered a biosphere. People have dabbled in creating artificial biospheres since at least Victorian times. On a small scale, you can go out and buy an ‘ecosphere’ which is a sealed glass ball filled with water. Inside the sphere is a little ecosystem consisting of shrimp, algae and bacteria, which isn’t very diverse. In 1986, Carl Sagan wrote a glowing article about these ecospheres called, ‘The world that came in the mail‘. Their makers say these glass worlds can last up to 10 years, but critics say the shrimp are slowly being poisoned by their own waste while starving. Perhaps a bigger biosphere is needed.

Biosphere 2 (earth is Biosphere 1) is a 3.14 acre sealed greenhouse in Arizona that is broken up into several different types of ecosystems. Each ecosystem included several species that filled the same ecological niche, and soils were seeded with micro-organisms in an effort to enhance diversity. In the early 90’s, an experiment was conducted by sealing in eight volunteers to simulate using a biosphere for space colonization. I remember seeing the ad for volunteers and being fascinated with the idea; however I had other commitments at the time and couldn’t apply – which is perhaps for the better.

These eight people to be were sealed into Biosphere 2 for two years where they grew their own food. Their atmosphere was also enclosed, so the only oxygen available came from the plants within the biosphere. It turns out the biosphere wasn’t a stable system: carbon dioxide levels fluctuated widely and oxygen levels couldn’t be maintained. All the pollinating insects died, while cockroach and ant populations overran the place. The people sealed inside couldn’t grow enough produce, forcing them onto calorie restricted diets.

One result of this experiment was to demonstrate that creating a stable biosphere is currently outside our capabilities. Since we haven’t successfully made a new biosphere, Biosphere I is all we have. So don’t get rid of all the diversity that pops up or moves in. Keep a little diversity at home.

How to be an algivore

powdered chlorella on a spoon

To start my investigation of algae, I cracked open an old textbook of my husband’s titled: ‘Introduction to Phycology’. According to the textbook, “algae is ubiquitous, occurring in practically every habitable environment on earth.” I agree as I don’t have to look far to find algae. My aquarium hosts all sorts of algae types resulting in periodic algal blooms, some less desirable than others. Walking into my bathroom, I can often find a pink alga growing on my shower curtain which would take over my shower if I didn’t regularly beat it back with bleach. Further afield, algae can be found thriving under Arctic ice and in deserts. I doubt there’s a more a resilient plant out there.

Plenty of critters thrive on an algae diet. Back to my aquarium, a farlowella (a stick-like fish with a suction-cup-like mouth) thrives on the green alga growing on the glass. My ever-expanding population of snails also dine on this alga. Out in the wild, frog and toad tadpoles live on algae. In fact, algivores reside all over this planet. Plenty of humans include algae in their diets – and have been doing so for eons. Apparently, ancient Aztecs considered spirilina (a freshwater microalga) a staple. Many coastal communities harvest seaweeds (a type of algae) all over the world and have done so for centuries.

In the alga eating spirit, I’ve decided to try eating (drinking actually) Chlorella vulgaris daily. Chlorella is a microscopic freshwater green algae. I bought a small tub of it in powdered form. Before I opened the tub, I expected chlorella to smell like pond scum, instead I got a pleasant surprise when the smell reminded me of a hayloft on a sunny day (still not a food smell). The powder is a dark forest green, so dark it’s almost black, with the texture of a ground up pigment.

my farlowella kindly cleaning the glass for me

It is easy to find glowing reports about chlorella (which I keep wanting to pronounce as cholera) as a superfood. I’m sceptical whenever the declaration of a ‘superfood’ is made, especially if the superfood was considered a ‘staple’ of an ancient remote civilization – everyday food never seems to be declared a superfood. Instead of eating a blackberry from my backyard, am I supposed to rush out and buy acacia berries from South American jungles?

There are documented benefits to eating microalgae. First of all, they contain all sorts of nutrients and complete proteins. Additionally, chlorella can reproduce itself four times every twenty-four hours, making it the fastest growing plant on the planet. This productivity is an important factor in considering food sources for our seven billion plus population. As for the health claims, I just don’t know. According to the internet, chlorella is apparently a cure-all, especially useful for ‘people with poor vitality’ (whatever that means). On the flip side, I’ve found web sites documenting digestive distress caused by consuming chlorella. I take the hype with a grain of salt.

Another well documented benefit to chlorella is how it improves air. Experiments have shown chlorella absorbs carbon dioxide and replenishes oxygen (important for long space voyages). If cultivated in tanks, eight metres squared of exposed surface is needed to keep one person breathing – which isn’t much considering the cultivation tanks could be shallow and stacked. These experiments were conducted in soviet-era Russia (1970s) where they made no effort to eat the stuff. NASA took the next step and looked at chlorella as the sole food source for astronauts on long space voyages – apparently they would survive, but I bet they would be grumpy.

As a food, chlorella poses a bit of a problem. It’s a single celled spherical alga with tough cell walls. These cell walls make it impossible to digest in its natural state. Processing of some form is required. Chlorella has a second problem – flavour. I’ve tried algae (in this case seaweeds) that have tasted fantastic, chlorella doesn’t. It isn’t that it tastes bad exactly, just unfamiliar. So far, I haven’t found any reference on how to make it taste good – just advice on masking its flavour in smoothies, or taking it in pill form. I tried it in a chocolate-banana smoothie, the smoothie was fine but there was no hiding the fact that chlorella was in there.

Apollo 18

Apollo 18 never happened – originally it was scheduled to land two people on the moon for a three day stay. Apollo 18 and future manned moon missions were cancelled due to budgetary reasons meaning, Apollo 17 was the last manned mission to the moon in December 1972.

I watched ‘Apollo 18‘ last night as snow, and the threat of more snow, prevented our expected dinner guests from arriving. The movie became the alternate evening entertainment. ‘Apollo 18’ is from my favourite genre – space horror (zombie movies are my second favourite – I have some unsophisticated tastes). This morning I was still thinking about the movie and it isn’t often that I keep thinking about movies after they are over. By the way, I might give away the ending here.

The movie is presented as a series of clips from the Apollo 18 mission to the moon. It’s presentation is similar to ‘The Blair Witch Project’ – which made me motion sick when I saw it in the theatre. ‘Apollo 18’s’ clips were better executed, thus easier to watch and they maintained a nice 70’s vibe to the footage. I think real moon footage was included. The cast was small and centred around the one guy orbiting the moon in the command module and the two guys camping out in the lunar module.

Apollo 18 is a secret military mission to the south pole of the moon which is why the public was lead to believe it was cancelled. The lunar module ends up landing only 2km from an ill fated Soviet mission’s lunar module and frozen cosmonaut remained (in reality the Soviet’s never made a manned landing on the moon). The astronaut’s mission goes downhill from this discovery.

There are aliens, which I thought were handled well. We never find out why they are there or what they really want. They aren’t humanish, nor do they speak English. We don’t even know if they really are evil, although that is implied. Also, the physics of space was handled well (I never expect it to be perfect) and air was a serious issue.

Over all I liked the movie even though a lot of the reviewers didn’t. I was left with one big question at the end, how did they recover the film?

As a tangent, I would be seriously on edge camped out on the moon even without strange things going on. Any creak or groan of the lander would put me on high alert as I’d be well aware that if something did go wrong there would be no one coming to save me. At least when I’m up in the Arctic, I know that if something went wrong rescuers would come – eventually.

A bit of space

Let’s go on a rocket trip to the moon!
We take out own air and water.
We need special suits, too.
In the sunlight, the moon is hotter than boiling water.
In the shade, it is very cold.
From the moon, the sky looks black.
We cannon hear any sound.
The mountains stand sharp and clear.
There are no plants or animals.
Jumping on the moon is fun.
We can jump six times as far as on earth!

– from Sun, Moon and Stars, 1950 by Jeanette Smith

How our understanding of things change with time is always interesting. It was once believed (before telescopes) that the moon as a perfectly smooth heavenly body. By 1609, Galileo Galilei looked through one of his homemade telescopes at the moon and saw that it was not smooth. Over the next century the craters were mapped and named.

One of the motivations for William Herschel (1738-1822) for making bigger, better telescopes was to observe life on the moon – at one point he believed the moon teemed with life. Eventually, with one of his better telescopes, he discovered the moon wasn’t inhabited – at least no cities were to be seen.

The above poem is from a children’s book written back in 1950, before anyone set foot on the moon. This poem got it right. Within twenty years of its publication astronauts landed on the moon and found it to be a dusty airless place.

Red moon, blue moon

Based on my recent discussion of blues (colours, not moods), I though I should describe what a blue moon is. ‘Once in a blue moon’ is a common phrase for an uncommon event. However, the moon is never blue (unless there are smoke or dust particles in the atmosphere, then the moon can appear bluish).

I’ve seen the moon turn a blood red – a frightening event if I didn’t know why it changed colour. On that night it was a lunar eclipse. The earth had moved between the moon and sun, casting the moon into its shadow. Normally, the moon reflects sunlight directly from the sun making it a bright feature in the night sky. When the earth is in the way, the only sunlight to reach the moon is refracted around the earth and as a result the moon takes on a blood red colour (at least it did on the night I watched).

A blue moon is a completly different event, more of a bookkeeping phenomenon. A calander month is on average 30.5 days long, while the time between full moons is 29.3 days. Normally, there is one full moon a month but, on a rare occasion, a month can have two full moons. There are different ways of determining which of the full moons is the blue one. Typically, a season has three full moons, however when one of the months has an extra full moon, the third full moon is condidered a blue moon. This is so rare, a blue moon will occur only seven times in 19 years, which works out to one every two to three years. Mark your calenders as the next one will occur on August 21, 2013.

Been reading ‘The Field Guide to Natural Phenomena‘ by Keith Heidorn and Ian Whitelaw – so far it promises lots of interesting tidbits.

Black jackets and being seen – or “How Not To Be Seen” for Monty Python fans

I recently bought a new jacket because my old one fell apart. I wanted a bright colour, easily seen by traffic when I walk to work on rainy, gray days (for obvious reasons). I also wanted my new jacket to be waterproof, again for those rainy days. I’m not much of a shopper, but I did shop around and the only jacket that I could find that met my criteria was black. So now I have a black jacket – the exact wrong colour for high visibility. As a teenager, I had a khaki jacket (army surplus) – a colour designed to blend into wilderness surroundings. I’d often wear this jacket camping. To be seen, I wore nuclear orange gloves that my grandmother had given me. From a distance often all that could be seen of me were the gloves. I actually loved the juxtaposition of my khaki jacket and nuclear gloves. Which brings me to how things appear to “stand out”, using sharp contrasts like my gloves.

Distinctive shapes also stand out. For example, our brains are hard-wired to see faces, even in bizarre places like stucco walls and clouds. For this reason, soldiers often paint disruptive green patterns across their faces when they want to vanish in the woods. Straight lines where they shouldn’t be also stick out as nature generally doesn’t have straight edges. Ever looked at a satellite photo of a wilderness area and had the square shape of a cabin pop out? Movement sticks out. I can find escaped crickets (we keep critters that eat crickets) on out cricket coloured carpets because they move. So, if you are hiding from bad guys: stay still.

On my walk to work I want to be seen. My nuclear orange gloves vanished years ago so I can’t rely on them. A retroreflector is an option which is just a good reflector set up to bounce the light right back where it came from irregardless of orientation. The shine from a cat’s eye when light hits it is an example. One type of retroreflector is a corner reflector, which is three mirrors put together like the inside corner of a cube. Since many small versions of retroreflectors can be put together as a thin sheet and attached to a fabric, clothing can be made from them. On a dark, rainy day I could wear a retroreflector band around my wrist which would bounce the light of car headlights back towards the driver, warning the driver of my presence. So my problem is solved, I need to find retroreflector wrist bands: but where else are retroreflectors used?

Retroreflectors have made their way to the moon both on American (Apollo 11, 14 and 15) and Russian (Lunakhod 1 and 2) spacecraft as a way to determine the distance between the earth and moon. This is done by aiming a laser on earth at the retroreflector and measuring how long the light takes to return back. This method has found the average distance from the earth to the moon is about 385,000 km. All the retroreflectors on the moon are still in use. They are the only Apollo experiment still returning data from the moon (I don’t know if there is Russian gear other than the retroreflectors still transmitting, but I doubt it) and has resulted in and improved knowledge of the moon’s orbit.

On a tangent… somehow the Russian Lunokhod 1 rover got lost. On November 17, 1970, Luna 17 arrived at the moon and released the Lunokhod 1 rover to explore. This rover trundled over 10 km, taking samples of the lunar surface and transmitting pictures, until its power ran out at year later. Since a retroreflector was mounted on the rover, scientists were able to keep track of it with lasers from earth until 1974. Then they lost track of it (not sure why because it was no longer moving). Recently, NASA’s Lunar Reconnaissance Orbiter spotted the rover’s tracks (remember, the only movement on the moon has been us and there is no wind to cover tracks) and was able to pinpoint the rover’s location. On 22 April 2010, a laser was bounced of its retroreflector once again.

So a retroreflector turns out to be an excellent way to be seen even from really far away. However, if you are really good with your optics, a retroreflector can be set up that will render one almost invisible.

Playing With Fire

I remember making candles when I was a kid. We filled empty and cleaned food cans with paraffin wax – the stuff that comes as a opaque block about the size of a deck of cards. The cans were then put into a bath of boiling water until all the wax melted. A few crayon stubs were added to each can, creating an array of colours. I tied a thick piece of cotton string, destined to be the wick, around a pencil for easy dipping. Next, I started dipping. With each dip another layer of wax clung to what was already there, increasing the diameter of the candle-to-be. I rotated through the colours, creating what must have been gaudy candles. When the candle was thick enough to stand on its own, the fun part began: we could light them.

A flaming match held to the exposed end of the wick has enough heat to vaporise wax within the wick and react with the oxygen in the air. Within moments a teardrop-shaped yellow flame flickers to life. The heat from the candle’s flame melts the wax, and the melted wax is drawn up by the wick, sustaining the flame. At its hottest, a candle’s flame can reach 1400 degrees Celsius. What is actually happening? Heat vaporizes the wax creating a gaseous cloud where the combustion takes place. Combustion is a series of chemical changes that converts molecules into new combinations – however this process isn’t totally efficient resulting in the production of heat and light. Light, along with its cousin heat, are part of the electromagnetic spectrum and signify the release of excess energy.

Candles used to be one of the main ways to create artificial light. However, compared to an incandescent light bulb, a candle produces 100 time less light, which is probably why candles are now mostly used to set moods, conduct rituals and provide light in power outages. I don’t often light candles, after all they are one of the leading causes of residential fires and they put soot and chemicals into the air I breathe. Some candle shops are so over-scented I can’t even stand being in them: I can’t imagine what my house would smell like if I burned their candles! But, when I do have a reason to light a candle, I enjoy watching the flickering flame – I find something about it quite mesmerizing.

One of the discoveries from experiments conduced in space is the importance gravity has in the formation of a flame. Here, in my mundane earth existence, when I light a candle the hot gases formed are less dense than the air around them, and so they rise in a process of natural convection into the familiar teardrop shape. This natural convection hinders complete combustion, so soot forms which makes the flame yellow. Out in my funky futuristic spaceship, where there would be no gravity (unlike the spaceships on TV), natural convection wouldn’t occur, and I would get a perfectly spherical flame. In space, my flame would require ventilation or it would smother itself. Its temperature would be evenly distributed and combustion would be complete, so soot would not form. The flame would be bluer and more efficient.

Another effect of gravity on a candle’s flame is the flickering. The frequency squared of a flame’s flickering is proportional to the force of gravity over the diameter of the candle. Meaning that a candle with a smaller diameter would flicker at a faster rate than one with a larger diameter. So a candle on another planet (with different gravity) would flicker at a different rate than the same candle on earth. A candle on my spaceship wouldn’t flicker at all (I would have to be mesmerized by its pretty spherical blueness instead).