Solar-powered calculators work the same way that other calculators work but use solar cells for power instead of batteries. Solar cells, also known as photovoltaic cells, take the sun's energy and turn it into electricity.
Solar cells can be found on satellites as well as calculators and can even help to power homes and street lights. The solar cells work by using the photoelectric effect, which is the ability of matter to emit electrons whenever light is shone on the solar cell.
Silicone is a semi-conductor and is found within a solar cell. When sunlight is shone on to a solar cell, the minuscule particles called photons hit the silicon atoms in the solar cell and help transfer the energy to loose electrons. These then work to make an imbalance with the silicon atoms as silicon atoms are tightly bound in their structure. Two different silicon elements are created: n-type and p-type. The n-type becomes positively charged, and the p-type becomes negatively charged, creating an electric field in the solar cell powering the calculator.
Solar powered calculators can make great additions to the classroom because they do not need to be powered off. They continue to work as long as there is enough light, for weeks on end.