Do you know what energy is? Scientists define energy as the ability to do work. That makes sense, because when you have a lot of energy, you feel like you can do many things. You might even say, “I have so much energy I feel like I could run 20 miles.” Running is work, and you would certainly need energy to run 20 miles. How does your body get energy? It comes from food. Food is the…
People long ago understood the changing position of the Sun from season to season. Ancient Greeks designed houses with window openings facing south, which is passive solar design. This allowed the Sun's heat and light to enter during winter. Ancient Romans added glass to their windows to help absorb and retain heat. They even passed laws against building tall structures that blocked sunlig…
Some energy sources, such as fossil fuels, take a long time to replenish. They are nonrenewable energy sources. Renewable sources, such as sunlight, replenish in a relatively short time. Listed below are examples of renewable and nonrenewable energy sources. …
Thermal flat-plate collectors collect solar energy. You may have noticed some homes and businesses with them on the rooftops. Thermal collectors absorb heat energy, also called thermal energy, from the Sun. They transfer it somewhere else to perform work. The collectors work well for heating water for swimming pools and hot water heaters. Greenhouses are solar collectors too. Plants grow we…
An American inventor built the first working solar cell in the 1880s. It was about one percent efficient. That means only one percent of the absorbed solar energy generated electricity. Since then, researchers have made solar energy production cheaper and more efficient. Solar cars are electric vehicles. They use solar cells to convert sunlight to electricity. The electricity is stored in battery…
With advancements in technology, you might think solar energy is a simple solution for the world's increasing need for energy. Unfortunately, it is not simple. Solar energy production has advantages and disadvantages, just like energy production from other sources. While sunlight is free, the cost of collecting and converting it to a useable energy is not. Cost is one factor people look at…
Use the solar timeline to learn some interesting facts about solar technology. 4.54 Billion Years Ago The Earth forms and begins to absorb energy from the Sun. 7th Century BC People use simple magnifying glasses to concentrate sunlight and make fire. 5th Century BC Greeks use passive solar housing design. 1st Century AD Romans use a form of glass in window openings to retain the Sun's heat…
atmosphere (AT-muhs-fear): a mix of gases that surround a planet efficient (uh-FISH-uhnt): working without wasting energy generator (JEN-uh-ray-ter): a machine that converts energy to electricity helium (HEE-lee-um): a light colorless gas that does not burn hydrogen (HYE-druh-juhn): a colorless gas that does burn industry (IN-dus-tree): manufacturing companies and other business insulated (IN-suh…