Posts Tagged ‘light’

Science of electronic cigarettes, as seen on the Tourist

// January 2nd, 2011 // 1 Comment » // How Things Work, Science in the Movies

Happy New Year! On the first of January, I went to see The Tourist. It promised to be an excessively attractive movie starring Angelina Jolie and Johnny Depp, the two best heartthrobs on screen. I won’t spoil the plot, but I will say that one cool gadget graces the scene. The electronic cigarette.

As described in the movie, the electronic cigarette does not emit smoke, just vapour. The one in the move was shaped like a cigarette, complete with a red LED light on the end for a burning ember. He tapped the end to put it out, but I don’t think that’s necessary. The automatic versions just turn on when you breathe in, a sensor recognizes the airflow, and I’d say it turns off afterward.

Electronic cigarettes, designed by Chinese company Ruyan “to resemble smoking”, come in a variety of designs. From classic cigarettes to cigars to pipes. Even a ballpoint pen, so you can look like you’re intelligently thinking witty thoughts while taking a sneaky huff.

All the designs have the same basic features. A cylindrical battery, a heating element, and a mouthpiece. When the sensor picks up air flow, it switches on the battery which heats up the element, vapourising the nicotine mixture absorbed on material in the mouthpiece. Manual versions lack a sensor, and you have to press a button to get them started. The nicotine can be replenished by dripping fluid refills onto the absorbant material, or buying a new prefilled mouthpiece.

An electonic cigarette

An electonic cigarette

But it’s the mixture itself that’s really cool. It comes in a variety of nicotine levels and a variety of FLAVOURS. Some are designed to taste like certain brands (such as Malboro), some taste like regular ciggies, some are menthol, and others come in tastes of caramel, coffee or vanilla. One recipe listed on Wikipedia contains hardly any nicotine, but 8% alcohol. That’s a 16 proof cigarette delivered straight to your lungs! Wow. Seems dangerous.

What I wanted to know was how do electronic ciggies compare to the real thing when it comes to health. It seems like we’re still unsure. Electronic cigarettes only hit the market in 2004, so they’re pretty new still. Most countries are taking a conservative stance. In England they can be bought in pubs and smoked indoors. In New Zealand they are only available in pharmacies. In Australia it is illegal to sell them, but they can be purchased over the internet for personal use, and I believe there are no laws against it. Please correct me if I’m wrong.

The debate seems to center around the fact that these electronic cigarettes are KIND OF tobacco products and KIND OF smoking cessation aids… but kind of not. No studies have been done to show that they could help people quit smoking and become nicotine free. To me it seems more like you would quit smoking cigarettes, and start smoking the electronic version instead.

And what’s the harm in that? Most of the damage caused by smoking is not due to nicotine itself. It’s all the other crazy chemicals that come with it which cause the cancer and lung damage and so forth. Nicotine is just the stuff that keeps people coming back. It’s highly addictive, working on the reward system of the brain and our favourite neurotransmitter, dopamine. Smokeless cigarettes are a way to enjoy nicotine without getting a hefty dose of dangerous chemical cocktails. Plus the secondhand smoke is safer. So it’s an example of harm reduction. Plus your teeth would get whiter.

Of course, nicotine is not exactly a friendly chemical. It might not cause cancer, but it IS highly toxic. 60 mg can be toxic to an adult. Nicotine is made by the tobacco plant as an insecticide, need I say more? In fact, it’s also made by other members of the Solanaceae (nightshade) family, such as tomatoes. That explains why my basil plant is getting torn to pieces by insects while the tomato plant right next to it is still intact. So maybe we don’t want to encourage people to smoke anything.

But gun to my head, I think the electronic cigarette is a good thing. I don’t think young kids are going to be swayed by sexy marketing into becoming the next generation of smokers. I don’t think we’d allow such sexy marketing in the first place. I don’t even know why the government allows cigarettes to be sold at all; the health problems must cost the economy millions every year. But what do you think? Do you think electronic cigarettes would be the lesser of two evils, or a new evil all on its own, ready to pounce on hapless youths and struggling smokers and catch them forever with nicotine claws.

Science that’s only skin deep

// December 3rd, 2010 // 2 Comments » // How Things Work, Recent Research, Science Communication, Sex and Reproduction

I’m a guest blogger for the RiAus, and this post also appeared on their fancy website. To tell the truth, I really wanted to call this post “Hormonally Yours” in homage to the Shakespeare Sisters (anyone?) but I’ll save it for another post.

Recently I was in Arnhem Land, visiting some Indigenous communities with a couple of friends. While I was there, I got pretty jealous of everybody’s darker skin. “It’s so well suited for Australia,” one of my friends lamented. “I should be in Norway or something.”

Pale skin like mine is not great for Australia. I tan pretty easily, but only after being burned bright red. While I was in the NT I slathered sunscreen religiously, but still managed to get a highly embarrassing burn on my lower back when I was building a sandcastle (an epic sand turtle, actually. Totally worth it.)

Anyway, enough about me and my weirdly tanned lower back (it’s been months! Why won’t it go away?) Let’s talk about Nina Jablonski, an anthropologist. In 2000 she suggested a new reason why skin colour varies so much. It’s not an adaptation to protect against skin cancer and sunburn, like I always thought it was.

It’s real job is to keep us highly fertile by maintaining a delicate balance between two key vitamins: Vitamin D and Folic acid.

Pica's skin tone matched her UVB exposure like her scarf matched her dress. Image by Monja Con Patines

Vitamin D is obtained through some foods, but mostly from drinking in sunshine. UV light turns cholesterol into Vitamin D, which then goes to either your liver or kidneys to be converted to an active form.

Once active it helps white blood cells like macrophages kill bacteria, and helps control levels of calcium and phosphate – important for building healthy bones.

Deficiency in Vitamin D causes rickets, a disease resulting in soft, easily broken bones and deformity which can lead to early death.

So getting enough UV (specifically UVB light) is important to not dying, and therefore having reproductive success later in life. It’s been backed up by Yuen, A. (Vitamin D: In the evolution of human skin colour DOI: 10.1016/j.mehy.2009.08.007)

Natural selection favours soaking up UV.

Penny stayed under foliage at noon to protect her folic acid. Image by Monja Con Patines

Folic acid is obtained in leafy vegetables and fortified cereals. Rather than being made by UV, the light can destroy folic acid by literally breaking it apart. (Jablonski, N. The evolution of human skin coloration DOI: 10.1006/jhev.2000.0403)

Critical for DNA synthesis, folic acid is essential during pregnancy when a lot of new cells are being made.

Folic acid prevents against 70% of neural tube defects in embryos. Its destruction by UV is bad news.

Natural selection favours avoiding UV.

So there’s an ideal amount of UV light that needs to get through the skin – enough to produce Vitamin D, but not too much to destroy all the folic acid. Getting the balance right for the environment you’re in means higher fertility, which drives natural selection

This is what Nina Jablonski thinks caused the evolution of skin colour through the sepia spectrum we see today. Dark skin, with high melanin, stops more UV light. That’s exactly what you want if you live in a place with a lot of sun, like places near the equator. Light skin lets more UV in, which is great if you live somewhere overcast and not very high on UV.

Understanding how your skin colour (NOT your race) influences these two vitamins is important in being healthy. It’s more important now than ever, because we humans travel a LOT.

Sadly, Australia is pretty high in UV and I am pretty white. Thank god for sunscreen.

Things are rarely that simple though, and I imagine there’s a few different things going on that connect UV light to skin colour.

On Tuesday the RiAus is holding an event called Skin Deep: Exploring human ancestry. They’ll be showing a preview of a new SBS documentary about skin colour scientific research, as well as results from the Genographic Project. Basically they took DNA samples from a lot of volunteers and some national identities, and now they’re giving us the goss on who’s related to who’s secret love child.

I’ll be there, I’d love to see you (though seats are limited.) I’ll be the one tweeting in the corner. Follow me @CaptainSkellett

Would love to hear from anyone who took part in the Genographic Project, and anyone who didn’t. Who would you most like to be related to? For me it’s David Attenborough, then I can dream of inheriting his voice.

What is a light cone?

// November 28th, 2010 // 1 Comment » // How Things Work

Simultaneous is not simultaneous. Space and time do not exist. These, and other strange and wonderful things, are the hallmarks of Einsteins Theory of Relativity and what we’re talking about today.

A few days ago I got Request a Post which read:
ahoy there, cap’tun! a prawn from beneath your deck speakin’. could you do a post on Light Cones? yeh know, the stuff Stephen Hawking talks about in the second chapter of his ‘Brief History of Time’? i’d love to read a simplified version. i simply can’t wrap the wiki article around my head! danke!

Ahoy there Prawn! Danke for requesting and here be yer post.

Something can’t move through space without moving through time as well. The Theory of Relativity dispenses with time and space, and instead describes a new thing called Spacetime.

Imagine a train moving in a straight line to the Eastward. We can map its movement through Space, Time or best of all, Spacetime! Notice how much more epically cool Spacetime looks. This will be important later.

With our Spacetime graph, we map space horizontally and time vertically.

In the realz world, there are three dimensions of space – length, width and height. Thankfully there is only one dimension of time, and this runs from past to future (unless you’re looking backwards.) To graph something using all four dimensions is hard, so instead we just take two dimensions of space and make a horizontal plane, then map time vertically. This will make sense in a second.

Now imagine a flash of light. Say you were standing on a hill on a moonless night and turned on a torch for a second. The light would spread out in every direction, lighting first the bushes near by, then later the trees in the distance. If we think about it in just 2 dimensions we can draw it like this, kind of like ripples in a pond.

If we map time vertically, and stack these pictures up above each other, we get a cone. So a Spacetime graph looks like this. Notice again that it is epically cool.

So a light cone is a flash of light moving through Spacetime. Usually people draw it as two cones. The bottom one is light collapsing into a single event, and the top one is it exploding out again.

Image by Deibid

You might be thinking – why bother?

Because this is a more accurate way to imagine the world. It shows how the past can influence the present and the future. When light cones overlap, it means two objects or events interact with each other. Every event in the Universe has an associated light cone. It’s a mathematical way to represent the Universe, and the basis for lots of complex physics (such as curved Spacetime, and why simultaneous events are relative to the observer.)

The theory of relativity replaced the absoluteness of space and time with the absoluteness speed of light.

I hope this answers ye question Prawn. Find out more about awesome light cones here.

Gold nanoparticles make plants glow in the dark

// November 8th, 2010 // 1 Comment » // How Things Work, Recent Research, The Realm of Bizzare

Image by Yellowcloud

Imagine if instead of having sensor lights to illuminate a garden path, you could line it with light-emitting plants. You could stroll along bio-luminescent flower beds, dancing in dappled moonlight and delighting in eerily lit peace, free from the shackles of electricity.

It could be possible with sea urchin shaped gold nanoparticles. Seriously, every time I turn on my computer the world gets more random. Sea urchins, I ask you. In any event, they’re called nano-sea-urchins.

Taiwanese researchers made a solution of gold nano-sea-urchins and dipped into it an aquatic plant, Bacopa caroliniana or blue waterhyssop. The nanoparticles moved into the plant over a day or so, and stayed there for about a month.

When exposed to UV light, the nanoparticles produced blue-violet light which encouraged the chlorophyll inside the plant to make red light. The result? An awesome glowing plant, just add UV.

It’s exciting stuff, there are a lot of excellent uses for light emitting things that work inside plants or animals. If the particles could be attached to a drug we could track exactly where the drug goes over the course of a treatment. You could attach it to proteins and find out where they are located inside a plant. Or you could just have a sweet glow in the dark plant in your house or garden.

Of course, you still need to have that UV source. But what’s wrong with having black light in your house or garden? Just think of the possibilities… You could drink tonic water every day, that stuff glows blue in black light because of the quinine.

Also, if you’ve ever wondered if black light can cause sunburn (as I recently have) here’s the low down. Black light is made of UV light which is close in wavelength to visible light, so it’s quite low energy. This counts as UVA, not UVB which causes most sunburns. Large amounts of UVA (such as those found in tanning beds) can cause skin cancer or premature aging, but the small amount contained in black lights is unlikely to do much damage.

ResearchBlogging.orgSu, Y., Tu, S., Tseng, S., Chang, Y., Chang, S., & Zhang, W. (2010). Influence of surface plasmon resonance on the emission intermittency of photoluminescence from gold nano-sea-urchins Nanoscale DOI: 10.1039/C0NR00330A

Hat tip to New Scientist

Solar powered laptop bags and handbags

// August 5th, 2010 // 7 Comments » // Science Art, Science at Home

Voltaic Generator Bag

Winter sun is something worth enjoying. Spreading out lizardlike and soaking up UV rays to make Vitamin D is an excellent endeavour. I often take my laptop out with me and blog in the sunlight.

Today as I was doing just that, my laptop started complaining about low charge. It made me wonder if you could solar power your laptop. Turns out you can.

You can have a panel on just about anything. Most only charge small devices like a phone, but you can have one on your desk, one on your bike, or even one on your hat (powering a small fan which spins faster as it gets more sun.)

The one pictured is a laptop bag with solar panels on the front, and it’s capable of charging a laptop. They charge a battery inside the bag, which you can run your laptop on.

Solar Handbag

I did a bit more snooping, and I found some fashionable handbags that do a similar job. These were sold on auction in mid July (one of a kind, probably couldn’t have afforded them anyway), and feature sexy solar panels that can charge your ipod, camera or phone as you walk.

It’s part of the portable light project, which has sadly finished. They create flexible photovoltaic textiles for use in developing countries. The material lends itself to traditional weaving and sewing, so people can incorporate the technology into their own culture. Open source electricity.

The solar units charge during the day, and at night work as lamps. They also have a USB port to charge phones, making it easier for traveling artists to connect with stores or midwives to seek clinic advice and diagnosis.

A mighty fine endeavour, but I’d be happy with something that quickly charged my iPod nano because he has problems. It leaks charge all over the joint like a poorly toilet trained puppy. I leave it switched off and locked in my bag, and next time I try to use it, it’s gone to Davey Jones locker. Perhaps it be time to update to an iPhone…






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