Waves
Hiya!
Today's topic I've never actually been taught so you'll have bare with my very knowledgeable approach (aka I have no idea what I'm doing but I shouldn't tell you that!). Wave goodbye to prejudice about waves, and jump right in! Happy reading!
Waves are transfers of energy. As you may know, we talk about waves as one of the four main methods of energy transfer (Waves, Mechanical, Heating and Electricity). There are three main properties of waves we need to know about; amplitude, wavelength and frequency.
The amplitude of a wave is the "Displacement from the position to the crest". In normal people terms, the amplitude is the height of a wave on average (you could look at it from the x-axis of a graph to the height). Don't worry, I'll put some diagrams in! The wavelength of a wave is "the length of a full cycle of a wave". Again, in simpler terms, it is the length of a wave to go up and down. Frequency is the number of complete waves that pass a certain point in one second or the number of complete waves that are produced from a source in one second.
It is important to know that there are two main types of wave; transverse and longitudinal. Most waves are transverse which means that the vibrations in the wave are perpendicular (90 degrees) to the direction of the energy transfer of the wave. I like to imagine this as a man running representing the energy transfer and his brother (representing the wave) running in between cones behind him. Waves like water ripples, light waves and other EM waves are the most common transverse waves.
If a wave isn't transverse, it will be longitudinal which means the vibrations are parallel to the direction of the energy transfer of the wave. Think of it like swimming, one arm after the other but being slightly pushed back by the water.. They consist of regions of compression (high pressure from many particles) and rarefactions (not a typo, caused by areas of low pressure from fewer particles). This type of wave is a lot less common, but examples include sound waves, ultrasound and shock waves.
We can calculate the speed of a wave by using this simple calculation. Wave speed= frequency x wavelength. The speed is measured in metres per second (m/s), the frequency is measured in Hertz (Hz) and the wavelength is measured in metres or sometimes centimetres (m or cm). The speed of the wave is often independent to the amplitude and frequency of the wave.
All waves can be reflected, refracted and diffracted. When waves arrive at an obstacle or surface, their direction of travel can change. This can be done by either reflection, refraction of diffraction.
Reflection of light is the reason we can see objects. The light waves bounce off of surfaces and reflect into our eyes causing this to be detected by our rods and cones in our eyes. If we have a non-smooth (rough) surface, the light waves are reflected at different angles but if the surface is smooth, these waves will be reflected at the same angle. We can say- the angle of incidence = the angle of reflection
Refraction of waves means the waves enter a new material but change direction. Diffraction is similar, it is where the waves can bend around obstacles which cause the waves to spread out. For example, white light rays can be diffracted around obstacles and can split into their individual colours (aka a beautiful rainbow!).
Today's topic I've never actually been taught so you'll have bare with my very knowledgeable approach (aka I have no idea what I'm doing but I shouldn't tell you that!). Wave goodbye to prejudice about waves, and jump right in! Happy reading!
Waves are transfers of energy. As you may know, we talk about waves as one of the four main methods of energy transfer (Waves, Mechanical, Heating and Electricity). There are three main properties of waves we need to know about; amplitude, wavelength and frequency.
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| The waves in this image aren't the right type but I thought it was a nice reminder that every cloud has a silver lining (Taken by me!!) |
The amplitude of a wave is the "Displacement from the position to the crest". In normal people terms, the amplitude is the height of a wave on average (you could look at it from the x-axis of a graph to the height). Don't worry, I'll put some diagrams in! The wavelength of a wave is "the length of a full cycle of a wave". Again, in simpler terms, it is the length of a wave to go up and down. Frequency is the number of complete waves that pass a certain point in one second or the number of complete waves that are produced from a source in one second.
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| My very skilled drawing |
It is important to know that there are two main types of wave; transverse and longitudinal. Most waves are transverse which means that the vibrations in the wave are perpendicular (90 degrees) to the direction of the energy transfer of the wave. I like to imagine this as a man running representing the energy transfer and his brother (representing the wave) running in between cones behind him. Waves like water ripples, light waves and other EM waves are the most common transverse waves.
 |
| My own personal analogy(it might not work for you but oh well!) |
If a wave isn't transverse, it will be longitudinal which means the vibrations are parallel to the direction of the energy transfer of the wave. Think of it like swimming, one arm after the other but being slightly pushed back by the water.. They consist of regions of compression (high pressure from many particles) and rarefactions (not a typo, caused by areas of low pressure from fewer particles). This type of wave is a lot less common, but examples include sound waves, ultrasound and shock waves.
We can calculate the speed of a wave by using this simple calculation. Wave speed= frequency x wavelength. The speed is measured in metres per second (m/s), the frequency is measured in Hertz (Hz) and the wavelength is measured in metres or sometimes centimetres (m or cm). The speed of the wave is often independent to the amplitude and frequency of the wave.
All waves can be reflected, refracted and diffracted. When waves arrive at an obstacle or surface, their direction of travel can change. This can be done by either reflection, refraction of diffraction.
Reflection of light is the reason we can see objects. The light waves bounce off of surfaces and reflect into our eyes causing this to be detected by our rods and cones in our eyes. If we have a non-smooth (rough) surface, the light waves are reflected at different angles but if the surface is smooth, these waves will be reflected at the same angle. We can say- the angle of incidence = the angle of reflection
Refraction of waves means the waves enter a new material but change direction. Diffraction is similar, it is where the waves can bend around obstacles which cause the waves to spread out. For example, white light rays can be diffracted around obstacles and can split into their individual colours (aka a beautiful rainbow!).
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