Electromagnetic Waves EQ: What is an electromagnetic wave and its properties?
Vocabulary Electromagnetic waves- transverse waves consisting of changing electric and magnetic fields
• Electromagnetic (EM) waves are made of vibrating electric and magnetic fields. • EM waves travel at the speed of light through a vacuum. • EM waves transfer energy and can interact with matter.
Vocabulary Radiation – energy that is transferred by electromagnetic waves Does not need a medium to travel Speed of electromagnetic waves all waves travel at the same speed in a vacuum, like space, EMW travel at 300,000 km per second When EMW travel through our atmosphere, they travel more slowly but they are still the fastest waves
Light – Waves or Particles? Light has many properties of waves, however, light also acts as though it is a stream of particles.
Stream of Particles Light is also made of tiny particles called protons. When light shines on some substances, it causes tiny particles, called electrons, to move. When this happens an electric current starts to flow. This is called photoelectric effect
Solar Energy Think of sunlight not as a wave but as a beam of photon particles for the purposes of explain the technical details of how home solar energy systems work. These bundles of energy penetrate the silicon lattice structure inside the solar cells making up a home solar panel and transfer their energy to an electron in the outer layer of the silicon atom. When a single electron gains enough energy from the penetrating photons, it breaks free and floats around the lattice structure, no longer bonded. An electron has a negative charge when it is knocked free during the photoelectric effect. The silicon atom that loses the electron, which had a neutral charge with the electron, now has a positive charge without it. Remember back to high school chemistry. Now, these high school chemistry and physics classes appear to have more relevancy as we learn about the photoelectric effect, silicon solar cells, and how home solar energy systems work. Who would have known?
Class Work and Homework Fill In What did I learn Confused Say Read pages O 76 – O 79, Questions 1-4, page 79