You may have realized that the sun gives off heat. It feels so good to feel the warm sun on our skin when we're cold! The sun has an amazing amount of heat and even though we only get a small amount of that heat, it's just the right amount for us. You also may have realized how much light it provides us. Without the sun, we couldn't see. What about the moon? The moon doesn't have any light of its own. All of the light we see is really sunlight that is reflected or bounced off our moon.
Working in groups, students build simple solar stills filled with salt water and observe what happens when the stills are placed in the sun. The students then taste the water they have collected and discuss what has happened in their stills.
This module addresses issues dealing with the energy from the sun, the energy needs of students in the classroom and, ultimately, our energy needs as a nation. Students will use a photovoltaic (PV) cell to measure the energy from the sun. Using a light bulb with a known wattage, the students will illuminate the bulb using a PV cell. This way the students will know the approximate energy coming from the PV cell.
These nine projects allow students to set up their own investigations and manipulate the variables that influence photovoltaic cells. The projects can be easily integrated into a normal science classroom curriculum, or can be completed by students individually for science fair projects. All of the projects will fit easily into classroom lessons surrounding scientific inquiry and the scientific method. They will also help illustrate concepts in electricity, light and color, velocity and gravity, chemistry and polarity, and could even lead to social studies or social action projects.
Concentrated sunlight is a versatile and high-quality form of energy with several potential applications besides producing heat and electricity. Today, scientists are developing systems that use concentrated sunlight to detoxify hazardous wastes, to drive chemical reactions, and to treat materials for increased hardness and resistance to corrosion.
As the popularity of photovoltaic (PV) cells and integrated circuits (IC) increases, the need for silicon also increases. Silicon is one of the most used materials in these two industries. It is an inexpensive and abundant semiconductor. However, the process of producing pure silicon adds cost, and it is generally unknown to the public. One of the first steps in producing silicon is a process called carbon-thermic reduction. Silicon dioxide (SiO2) that is found in beach sand and quartz is melted down in a caldron at a temperature of 1450 degrees Celsius.
Students model the flow of energy from the sun as it enters a photovoltaic cell, moves along a wire and powers a load. The game-like atmosphere involves the younger students and helps them understand the continuous nature of the flow of energy. For a related lesson, please see the activity “Solar Powered System” (PDF 430 KB).