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## Sharing knowledge to build rich, sustainable lives.

 Appropedia is for collaborative solutionsin sustainability, appropriate technology and poverty reduction. You are welcome to add to and edit Appropedia - your site to find, co-create and improve the solutions we need. Our vision and mission. Contributors have made 279,879 edits and uploaded 21,894 files.Browse our categories or all 6,177 articles.

## Announcements — more

 As part of a 3-D printing class, graduate students will be designing printable open-source appropriate technology for sustainable development. If you want a technology designed to be 3-D printed, post your ideas here. Chosen designs will be made and open-sourced for the global community. Deadline Nov. 13, 2014

Aleiha's parabolic solar cooker. The paraboloid is an interesting shape with some amazing qualities. It has the power to concentrate light, electronic waves, sound, etc. to its focus at the center. To find the focal point of a paraboloid, one must use the formula, $y=p*x^2$, where p is a constant. The variable y is the depth of the dish, and x measures the distance from the center axis to the maximum circumference of the dish. You have to pretend that there is an x axis going through the center of the base of the dish and a perpendicular y-axis passing from the center of the base of the dish to the focal point. The two numbers, x and y, represent a point on the paraboloid, and from that, you are able to determine where the focus is.

Parabolic cookers have been used for centuries now. The idea to concentrate light using curved mirrors was developed by the Greeks, Aztecs, Incas, Romans and Chinese. The Incas used bronze and gold for their mirrors and they built structures that were several stories high. This technology seems to have appeared around the same time for each of the civilizations. It is thought that Archimedes harnessed the technologyW to defend Syracuse from invading Roman fleets in 212 BC.

Building a solar powered (photovoltaic) vaccine refrigerator with a community hospital in Northern Mexico. Now the sun helps keep the vaccines consistently cold.

 All of humanity now has the option to "make it" successfully and sustainably, by virtue of our having minds, discovering principles and being able to employ these principles to do more with less.

## Visit the Solar Portal

Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.

Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.To harvest the solar energy, the most common way is to use solar panels.

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

Selected service learning Projects gallery (refresh)

ENGR 215 Introduction to Design projects – Spring 2010: RCEA: Two labs of the Spring 2010 semester of Engineering 215 worked with the Redwood Coast Energy Authority to build energy education boxes for classrooms in Humboldt County. These boxes are designed for different K-12 grade ranges and cover one of three topics: energy conservation, renewable energy or climate change.

Spring 2010 ENGR 215 Intro to Design Projects - RCEA
 The Power of WindEducates students on the basics of wind power
 Weather WarningsTeaches climate change through a movie, three stations, and a worksheet
 Modeling Renewable EnergyEducates students on many types of renewable energy
 Bust-A-WattTeaches energy conservation through activities, home assessments, and an art assignment
 Seas of ChangeEducates students about the polar ice caps melting effects of climate change through a hands-on model
 Energy in a CinchTeaches about renewable energy through the use of a Windbelt
 CAN YOU WorKITStudents assemble and operate a hand crank electrical generators

## Selected categories

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## Construction zone — correct mistakes & flag spam as needed

 Newest articles more Wanted pages - click to add info more New pages being developed: Note: Appropedia's newest pages may not yet comply with our policies. Page titles in italics are "redirects," often created when moving a page. Create a new page: These red links are invitations for you to contribute your knowledge. Or create a page on the topic of your choice. Newest files - images and documents that can be added to pages more Ethical-filament.png J.M.Pearce 12:52, 21 September 2014 31 KB Ethicialfilament.jpg J.M.Pearce 06:38, 20 September 2014 316 KB Riverside Park 693.jpg Philralph 00:44, 19 September 2014 115 KB LGMarshallAvatar.jpg LGMarshall 08:59, 18 September 2014 145 KB Oak Leaf Trail.jpg Philralph 02:34, 18 September 2014 124 KB Note: Appropedia's newest files may not yet comply with our policies.