The real waves

To travel from one place to another the waves vibrate/oscillate in a displacement/distance graph. The distance is how far the wave has traveled from its starting point, while the displacement is how far the wave has gone up or down. The maximum/minimum displacement is known as the amplitude. A wavelength is the distance of one complete oscillation, which can be from crest to crest. The top of the wave is called a crest while the bottom of a wave is called a trough. If we have changed the x-axis from distance to time, then the distance of one complete oscillation is then a time period and this is just the time it takes for one complete oscillation. Now to measure the frequency(hz) we use the time period(T) Formula: [f=1/T]. frequency is measured in hertz and is a number of complete oscillations per second. We can also use the equation the other way around [T=1/f]. To find the speed of the wave is going to be wave speed(m/s) = frequency (hz) x wavelength (m)

In transverse waves the oscillations are perpendicular to the direction of the energy transfer or the direction in which the wave is moving. The transverse waves the vibrations are going up and down while the overall wave is travelling left to right. Some transverse waves are  electromagnetic waves, light, radio waves, ripple/waves and the waves of string like on guitar. Longitudinal waves on the other hand have oscillations that are parallel to the direction of energy transfer. Some regions are spread out while others are regions that are more compressed because the waves vibrate back and forth. In motion the regions that are compressed are moving left to right. Longitudinal waves sound waves and some shock waves like seismic p waves.

There are 4 different types of waves. Pulse waves is when one lonely crest travels through the rope, then there's a continuous wave which is what happens when the wave is moving up and down, an oscillator is anything that causes an oscillation or vibration in a wave. A wave’s energy is proportional to its amplitude squared. For example, if you double the wave's amplitude you get four times the energy, triple the amplitude you get nine times the energy. If you have two identical pulses, both crests along a wave one from each end, when the two pulses overlap, they’ll combine to make a crest, with a higher amplitude than the original ones. That is called constructive interference, the waves build on each other. On the other hand, you have destructive interference which is when both waves have the same amplitude but one is a crest and the other is a trough, then they both cancel out at the middle.

Three different things happen when a wave arrive to a boundary, it can be absorbed so the energy from the wave is transferred to that’s material’s energy stores, the second thing that can happen is that wave can be transmitted where the wave enters the material and passes through the other side which often leads to refraction and the last thing is reflection which is when the wave bounces/reflected of the boundary. For reflection: angle of incidence = angle of reflection. Refraction is when waves change direction as they pass through from 1 medium to another, this happens because different mediums have different densities. The higher the density of the material the slower the wave will travel through the medium. If the wave hits the medium as a straight line then it will pass through as a straight line but when it hits it at an angle it will be refracted meaning that the direction will change. the more dense the more it will bend towards the normal straight line 

Electromagnetic waves are all transverse waves. The wavelength and frequency in electromagnetic waves are inversely proportional, meaning if the wavelength goes up then the other one goes down. in the table of electromagnetic waves, left to right the frequency increases while the wavelength decreases. Our eyes are only able to detect visible light which is 10^-7m and it gives us all the difference we can see. Electromagnetic waves are made up of oscillating electric and magnetic fields. 

Radio waves are a part of the electromagnetic spectrum and they have the longest wavelength and the lowest frequency. We can generate radio waves using electricity in the form of an alternating current(made up of oscillating charges). To generate radio waves first we have an oscilloscope connected to a transmitter, oscilloscope allows us to see the frequency of the alternating current(determines the frequency of the wave we are going to produce) once the radio wave is generated we can detect it with a receiver(absorbs energy, generates an alternating current) also connected to a oscilloscope which then has the exact same frequency as the original one. This process allows us to transfer information. There are three types of radio waves for communication: long waves, short waves, very short waves. Long waves can be transmitted huge distances with no interaction, they diffract(bend) around the curved surface of the earth, great for long range communication. Short waves can also travel long distances but are not able to curve around the earth. Instead, reflected from the ionosphere(electrically charged layer of the upper atmosphere) also can be used for short distances such as bluetooth. Very short radio waves are used for TV and fm radio, have to travel directly from the transmitter to the receiver, hills and tunnels can get in the way, not very effective.