Waves ……….the facts are here!

What are waves? Click on the middle circle first. You can then work round the others to find out more! Waves radio Revise waves lightinfra redultravioletX-raysgamma raysmicrowaves Click here for more science revision games from Dartford Technology College!here

Travelling by waves Waves can be either: LongitudinalTransverse Waves on the surface of the sea move up and down – they are transverse The coiled spring on this toy pushes the rider up and down but the waves are squashes and stretches of the spring. These are longitudinal. squash stretch

Transverse waves on the sea …make you seasick!

Transverse waves only transfer energy We think that waves actually move things along the surface of water….but do they? Watch the blue dots on the animation - what happens to them? Animation courtesy of Dr. Dan Russell, Kettering University

Transverse waves Waves can be drawn as diagrams like this The height of waves can be measuredin meters (m) The length of waves can be measured in meters (m)

Amplitude and wavelength This transverse wave is like a piece of rope being waved up and down above the ground The red line shows what the rope would be like if it was held completely still and taut. The purple line shows the wavelength The orange line shows the height or amplitude of the wave Animation courtesy of Dr. Dan Russell, Kettering University

Longitudinal waves Most waves of energy travel as longitudinal waves… Model of air particles as they hit into one another Sounds that we can hear travel as vibrations of air particles, a bit like this: The air particles are made to vibrate as the musician plays There’s more! Animation courtesy of Dr. Dan Russell, Kettering University

Another view of longitudinal waves The red bar pushes the particles making them vibrate backwards and forwards Waves of energy pass through the particles making them squash together (compressions) and spread out (rarefactions) Watch just one particle – does it move along from one end to the other ? Animation courtesy of Dr. Dan Russell, Kettering University

Frequency of waves You have already seen how we can measure the amplitude (height) and the wavelength of waves. We can also measure the frequency of waves - how many waves are produced in one second The frequency of waves is measured in hertz 1 hertz (hz) means 1 wave per second Question: If you wave a rope from side to side three times each second, what is the frequency of the waves produced?

Answer Your question was: If you wave a rope from side to side three times each second, what is the frequency of the waves produced? The answer is 3 hertz (hz) ! Did you get it right? Well done!

Testing time! You should now have looked at all the information about the two types of waves. Now go to the next link to test your knowledge. If you are not sure, click this link to start again. When you have got all the questions right, return to the start of the module and continue working!