![]() ![]() Let us take a wave moving horizontally left to right. We start with the direction the wave is going. Which type it is depends on something quite simple. One type of wave is known as longitudinal, and the other is transverse. Speed = wavelength x frequency Types of Waves What if the buses from the example before stayed the same distance apart (the wavelength stays the same) but they all drive twice as fast – will that change how frequent the buses are? Yes – we will see twice as many buses per second! So the speed of the wave is also important, and there is a formula called the “wave equation” which links the wavelength, frequency and speed for waves that travel from one place to another: We now have to start thinking about an extra thing – what is the wave itself is moving? Some waves are “still” (like the hand waving back and forth, a clock pendulum), but most waves actually move from one place to another with a speed. If the period is short, we will have many repeats (high frequency), if the period is long, we will have less repeats (low frequency). We can also quickly thing of something else – what about the time between repeats? This is called the period, and is linked to the frequency. Frequency is measured in Hertz (Hz), which means “per second.” So if there were 10 buses every second (unlikely, I know) then the buses have a frequency of 10Hz. If we consider the distance between buses to be a wavelength, then we could sit and measure how many buses come past every minute, or every hour. Think of buses: some are frequent, some are not. However, this diagram is like a snapshot, but we know there is movement back and forth in waves, and this gives rise to a frequency. Another thing to realize is that if you take a walk along the wave, you would be repeatedly going up and down, just like you do floating in the sea as waves go past! ![]() The amplitude is always measured from the midpoint to the wave in a vertical line. Notice the wavelength measured in three places, always between two successive (identical) points. If we draw a diagram to show the displacement changing (going back and forth) along a distance scale, we have a wave, and it looks like this: Next is the wavelength, which is the distance between two successive identical points on a wave (think of the repetition again, it is the distance between repeats). Firstly, we will call the size of the movement the displacement, like the height of a wave, with the maximum height called the amplitude (always measured from the midpoint – see the diagram below). Let us think of certain facts that we know, so that we can construct a general wave model. The “something” could be almost anything, like particles (so small and fast we cannot see), large objects like a pendulum, and even energy. That is what waves are about, something moving back and forth repeatedly. Both these things have something in common: repeating movement over time. Think of hand moving back and forth, or waves on water. As waves appear everywhere in our everyday lives, it makes sense that we should know exactly what they are and how they behave. ![]() Waves are extremely important, without them we wouldn’t have cell phones, microwave ovens, cable TV and the Internet. Introduction to Waves Written by tutor James F. The Periodic Chart of Table of the Elements.Explanation of States of Matter Problems.SN1SN2 – Nucleophilic Substitution Reactions.Explanation of Numbers and Math Problems – Set 3.Explanation of Numbers and Math Problems – Set 2.Explanation of Numbers and Math Problems – Set 1.Metric Prefixes and Their Origins and Use.Drawing Cyclohexane Rings – Organic Chemistry.Alkanes and Alkenes – Organic Chemistry.Light & Dark Reactions in Photosynthesis.Search Lessons Search for: Science Resources and Science Lessons – Science Help ![]()
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