Waves
Waves transfer energy and information, but not matter.
Waves are either transverse or longitudinal
Transverse Waves
A transverse wave vibrates perpendicular (90 degrees) to the direction in which the wave transfers energy.
Imagine a sea wave is moving towards the shore, you will see the wave vibrating up and down as shown below
Tranverse waves and mediums.
A medium is what a wave travels through e.g. air, water etc.
Transverse waves can travel through solids and the surface of the water.
Generally transverse waves cannot travel through the body of a liquid, or through a gas!
However, some electromagnetic waves, which are also transverse can travel through solids, liquids, gases or even a vacuum!
Examples of Transverse Waves.
Ripples on the surface of water.
S- waves (Secondary waves), these are a type of seismic (earthquake) waves
Any electromagnetic wave such as Radio waves, microwaves, Infrared, Visible light, Ultraviolet, X-Rays or Gamma Rays.
Slinky spring and Transverse wave
When a slinky spring is moved up and down vertically, a transverse wave will travel through the spring as shown in the diagram below:
The wave is transferring the energy forward, but the vibration is vertical. So, vibration is at 90 degrees to direction in which the energy is transferred.
Wave diagram for a Transverse Wave
Key Terms
Wavelength is the distance from a point on a wave, to the same point on the next wave. Measured in metres.
Peak or crest is the top of the wave
Trough is the bottom of the wave
Amplitude is the maximum displacement (distance) from the mid point of the wave. It is also a measure of the energy of the wave.
Key tip for drawing the wavelength
Draw the wavelength from peak to peak, or trough to trough.
A common mistake is to draw the wavelength from one shoulder to another, which makes it slightly shorter. See the diagram below!
Make sure you draw the wavelength like the one in the black, not the one in blue!
Practice Question
1.What do waves transfer?
2.State the names of the two types of waves
2a. Write definition for a transverse wave
3. Give two examples of a transverse wave
4. State the definition of the term wavelength.
Absorption and Emission of EM Radiation
JJ Thomson and Plum pudding model
Ernest Rutherford and the Nuclear Model
Niels Bohr changing the Nuclear Model
Discovering the Proton and Neutron
Measuring radiation from radioactivity
Radiation types and properties
Random nature of radioactive decay
Radioactive contamination or irradiation
Hazards of contamination and irradiation
Studies on the effects of radiation on humans
Different half lives of radioactive isotopes
Nuclear Fission Chain Reaction
Writing nuclear fission equations
Accordion Content
Accordion Content
Accordion Content