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Posts Tagged ‘solar’

It Predicts Solar Eclipses, and Its Made of LEGO!

December 10, 2010 Leave a comment

The video is on the Scientific American website, and I can’t embed the video here unfortunately. (Not being able to do things like embed videos is starting to bug me, so I may get my own domain soon).

[Update: The video is now on YouTube, so I can actually post it here (woohoo!), but you should still check out the Scientific American page for the article about how the video was made. Its pretty interesting]

But definetly check out the video here!

Its a (LEGO!) replica of the Antikythera Mechanism, an ancient Greek machine which was built to predict the date of solar eclipses with incredible accuracy.

The Antikythera Mechanism. Via Wikimedia Commons

It was discovered in 1901, but its true purpose was not puzzled out until a few years ago.

Freakin’ cool!

Awesome Video of the Moon Crossing the Sun

October 20, 2010 Leave a comment

The Solar Dynamics Observatory (SDO)

is designed to help us understand the Sun’s influence on Earth and Near-Earth space by studying the solar atmosphere on small scales of space and time and in many wavelengths simultaneously.

 But also (and perhaps more importantly), it takes some pretty sweet pictures and videos.

 Take this one which I saw posted on Bad Astronomy. It shows the moon moving between the SDO and the Sun, making the moon clearly visible as it crosses the disc of the Sun.

 Cooooooooooooool!

Feel The Heat! US Approves Thermal Solar Power Plant

September 2, 2010 2 comments

Solar power is the future. There are lots of ideas for renewable energy out there, but I am convinced that solar will be the only energy source truly strong enough to handle our power needs.

So we got some good news to that end! The first solar thermal power plant in the United States just got approval to be built in the great (sunny) state of California.

The approval is for a 250-megawatt solar thermal power plant by the Beacon Solar Energy Project. The approval came as a direct result of the green energy incentives granted by President Obama.

The plant will operate on over 2000 acres of land and will use abut 521 million gallons of water annually.

So, I wrote a post awhile ago on the Physics of Solar Power. That post described how semi-conductors are used to make the more common photovolataic cells used to generate electricity using the sun’s energy.

Thermal solar plants work differently. What happens is that a series of parabolic mirrors are installed in long rows surrounding one large tower in the centre. The mirrors will follow the sun throughout the day they are angled in such a way that the sunlight will be focused on water filled tubes.

Thermal Solar Power uses mirrors to direct sunlight onto a central tower, heating water into steam and driving turbines.

These tubes will then get extremely hot, several thousand degrees in fact, and the steam generated will be used to spin turbines, and thus generate electricity.

Its a bit less fancy than the semi-conducting solar panels, but it produces electricity just the same. And 250 megawatts is nothing to sneeze at either; thats enough to power 200,000 homes!

And lets not stop there! The final approval of a 1000 megawatt solar thermal power plant (The Blythe Solar Power Project) is nearing completion. This plant will also be built in California, be 7000 acres large and will generate enough electricity to power 800,000 homes!

The Physics of Solar Power

July 6, 2010 2 comments

In my previous post, I discussed how President Obama is helping to fund the development of Solar Energy. I thought I would then take the opportunity to explain a bit of the physics behind solar power.

Don’t worry, you won’t find any equations here :)

First, lets start with the sun. That big bright thing up in the sky.

The sun generates light, and light can be thought of as a bunch of tiny packets of energy. These packets are called “photons”. The different amounts of energy in a photon will correspond to the colour of the light that is emitted. For example, photons of the colour blue have more energy than photons of the colour red.

Energy increases from left to right (Source: Opensource Handbook of Nanoscience and Nanotechnology)

 

So how do we harness the energy in these photons? We can use Photovoltaic cells. Put simply, they convert solar energy into electricity. Let’s see how…

A photovoltaic cell is made of special materials called semiconductors, which are made of things like silicon (Yes, that stuff used to make fake boobs. Isn’t science awesome?).

Now, all atoms are made up of a nucleus (which is made of protons and neutrons) and electrons which circle around the nucleus.

Electrons can actually absorb the energy from a photon, but this happens only if the photon has a very specific amount of energy (a specific colour). When an electron does absorb a photon, it causes the electron to “jump”, and sometimes even break free of the entire atom! Electricity is a constant flow of electrons, which we refer to as an electric current.

Silicon structures like to hold onto their electrons. They don’t normally let them move around which makes silicon what we call an insulator. But in a Photovoltaic cell we add impurities, little bits of stuff that doesn’t belong there. The impurities will actually encourage the silicon to release its electrons and let them move around.

Now the magic happens. So a photon (those little packets of energy from the sun) hits the Photovoltaic cell. If the photon has just the right energy, it will knock loose one of the electrons in the silicon atoms. And, because of the impurities, that electron will move around.

If you get enough electrons moving around, you get an electric current which we can then use to power all of our awesome toys!

Thats it in a nutshell. If you want to read about this stuff in a bit more detail, check out the links spread all through this post, or some of the cool sites below.

Hooray for Physics!

Further Reading:

http://science.howstuffworks.com/solar-cell.htm

http://www.physlink.com/Education/AskExperts/ae451.cfm

http://science.nasa.gov/science-news/science-at-nasa/2002/solarcells/