Electromagnetic radiation is basically particles that act like waves. The EM spectra is continuous which means it has no gaps, holes, or breaks of any kind.
All electromagnetic waves travel in a vacuum at a speed of 3.0 x 10 cm/s. (write down
Now what does an electromagnetic wave look like? (write EM wave, with question marks around it) Here, let me show you. (either start a new recording or drag wave example down)
The waves are a cycle, the cycle starts at the origin. (label the origin) The origin is where the wave begins and where it will return to. The amplitude (label amplitude) of a wave is the height of the wave from the origin to the crest (label crest). The wavelength (label wavelength) is the distance between the crests. Frequency is how many wave cycles pass a given point per unit of time. To put it simply, the smaller the wave lengths, the higher the frequency. The bigger the wavelengths, the lower the frequency. You can think of frequency and energy being proportional to one another. The higher the frequency, the higher the energy.
Frequency is measured in hertz(show hertz symbol). From one crest to another is a completed cycle of a wave (drag finger along completed cycle) This is what the entire electromagnetic spectrum looks like(place picture down). At one end of the spectrum is radio waves(point out radio waves). Supposedly, one radio wave is as long as a football field(pull down football field doodle), and have the least amount of energy. Radio waves are what we use to broadcast(pull down radio tower doodle, then draw the signal marks). Next is microwaves which have more energy than radio waves due to shorter
wavelengths. I’m sure we are all familiar with a microwave ovens(pull down microwave oven).
These use, wait for it,(pull down food doodle) microwaves to heat the food. Then there’s infrared waves(point it out). We can’t actually see infrared but we do feel them as heat. The sun, fire, and living creatures (pull down these doodle in order) all produce infrared waves.
The next one is visible rays. This is light. This is the only EM spectrum we can see and are able to perceive. This spectrum starts at the color red, then goes…