Renewable Energy
Renewable energy is power from sources like wind, sun, and water that never run out.
A kitchen window lets sunlight stream onto the counter each morning. That light warms the room and helps plants grow on the sill. The sun comes back every day. It never runs out. A candle on that same counter slowly melts down to nothing. Once the wax is gone, the flame dies.
Explaining renewable energy by grade level
Wind blows every day and never runs out. A small wind wheel can spin and make power from that wind. The faster the wind blows, the more the wheel spins. That power comes back each day, so it never gets used up.
Projects that explore renewable energy
Wind is a renewable energy source because moving air is constantly replaced by weather patterns. A windmill converts that moving air into electricity through blades connected to a generator. Blade angle turns out to matter more than most people expect: at 75 degrees, every blade size that spun produced the highest current output.
The Earth makes heat deep below the ground all the time. That heat turns water into steam. In this model, steam from a pot shoots through a small hole in foil and spins a pinwheel. Fewer holes make a stronger jet and a faster spin.
Methane gas from cow manure is a renewable energy source because bacteria keep producing it as long as organic material is available. When three sealed flasks of manure and water sit at 14, 24, and 34 degrees Celsius, a tube from each leads to an inverted water-filled measuring cylinder where the gas collects. After five days, the flask at 34 degrees Celsius produced the most methane by a wide margin.
Wind turbines harvest renewable energy by using blade surfaces to capture kinetic energy from air that is endlessly replenished by atmospheric circulation. The angle of each blade determines how effectively it redirects wind force into rotation. In this experiment, voltage rises steadily as the angle increases up to 75 degrees, where the turbine produces its peak output of 0.95 volts.
Ocean waves carry energy because wind continuously transfers its force to the water surface, creating an endless supply of motion. A wave energy device converts that motion into electricity by rocking a magnet through a coil as waves roll through. Testing wave heights from 10 to 40 cm at two speeds shows that both wave height and wave speed affect how much voltage the coil produces.