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A sun jar is a jar which contains a solar-powered light emitting diode (LED). During the day, a small solar cell inside the jar charges a battery, and at night, the battery powers the LED, causing the jar to light up. This green gadget can be found in stores which carry various environmentally friendly lighting options, including science stores, and people can also make their own sun jars. Putting a sun jar together does not require very many skills.
The most basic sun jar design is simply a frosted glass glass jar. The LED inside may be colored to create colored light, or the frosting on the jar can be tinted for the same effect. Frosting helps to diffuse the light from the sun jar, making it less harsh, and it also hides the innards of the jar, which are not very visually interesting, during the day. The shape of the jar is not critically important and people may have jars of different sizes and shapes for more visual interest.
In some designs, the sun jar is completely sealed, which means that it can safely be used in damp environments. In these designs the top of the jar is left clear to allow the solar cell to charge during the day. Other designs have lids which must be swung open to expose the solar cell during the day and then swung shut at night for the jar to operate. In either case, the sun jar needs to be in direct sunlight during the day to charge.
Sun jars typically have light sensors so that the jar only illuminates in the dark. The sun jar can provide a night light, or multiple jars can be used for mood and atmospheric lighting. In the garden, sun jars can provide a reliable source of night time lighting which will not require maintenance. Campers may find sun jars too bulky to pack out with them, but for small and short trips sun jars can be handy for night lighting.
One popular do it yourself sun jar assembly technique involves taking apart solar powered garden lights and putting their innards into frosted jars. Sometimes buying and dismantling solar lamps is actually cheaper than purchasing the individual components from an electronics store or store which stocks solar supplies. People may want to price out their options to see whether a commercially produced sun jar or homemade version is more affordable.
@Sara007 - Making a solar cell is a lot of fun but don't expect it to give off much energy. While your sun jar lamps are powered by a professional grade solar cell, the ones you can make at home out of copper and house scraps are move for demonstration rather than anything else.
There are some auction sites that sell sheets of solar cells at reduced prices, so in theory you could make your own solar panels cheaper than you could purchase them. I guess it all depends on what you want to do with the solar cells once you have them. No matter what, have fun with the project. It's great to hear that kids are interested in science.
Making solar powered sun jars is a great science project to work on if you have kids. You can get really creative with the look of the jar as long as the solar cell has easy access to the sunlight.
The sun jars we made we use to light our walkways at night. We could have just purchased garden lights but I thought that sun jars were a lot more educational.
Our next big project is to actually make solar cells. They actually don't require as much work as you would image. Just a bit of cash, an auction site, and a really steady hand.
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