IGCSE Coordinated Science: General Wave Properties General Wave Properties 1 Demonstrate understanding that wave motion transfersenergy without transferring matter in the direction of wavetravel. The statement is what it says above. However, I want to clarifysome things in terms of how a wave motion can transfer energywithout actually transferring any matter. Consider the following example. You’re friend is on a swing.Let’s just assume that you’re friend is incompetent and you haveto push him. You push him, but you don’t have to ﬂy o withhim, your mass can stay where it originally belonged (on theﬂoor). You simply have to transfer the kinetic energy from yourmuscles (I assume you’re pushing your friend with your hand),to his swing. Basically, you’re pushing his mass with a bit ofyours, which allows the swing to have enough energy to elevatethe swing , but you don’t have to physically ﬂy o as well. Long story short, wave motion transfers energy, however thematter does not have to be transferred. 2 Describe what is meant by wave motion as illustrated byvibration in ropes and springs and by experiments using waterwaves. Wave motion is the transfer of energy from one point toanother. E.g.
● Vibration in ropes: Particles in rope vibrate in a ﬁxedposition and energy in the particles are transferred fromone end of the rope to the other end. Wave travels as a“sideway pulse” ● Water ripples: An object that is ﬂoating experiences both“up and down” motions. 3 State the meaning of and use the terms speed, frequency,wavelength and amplitude. Amplitude The maximum displacement a point moves from its restposition when the wave passes. Since this is displacement, weusually give amplitude the same units as we would fordistance/displacement. E.g. metre, kilometre Frequency The number of waves passing any given point each second,measured in Hertz (Hz). Waves of di erent frequencies. Wavelength ( λ ) The shortest distance in which two closest points on a wave arein phase. Measured in metres, kilometres etc. Example below:
4 Distinguish between transverse and longitudinal waves andgive suitable examples There are ultimately two types of waves: Transverse Waves: Wave oscillation is perpendicular to direction of energypropogation Examples include: ● Seismic S waves ● Light rays ● Electromagnetic waves Longitudinal waves Wave oscillation is parallel to direction of energy propogation Examples include: ● Seismic P waves ● Sound waves. 5 Identify how a wave can be reﬂected o a plane barrier andcan change direction as its speed changes.
Reﬂection: If a wave hits a mirror plane, and the plane is niceand smooth, the wave will be directly bounced o and reﬂected. Refraction: If the surface of the mirror/medium has interferenceand is not completely smooth, the wave is partially reﬂected butmost of the wave will be refracted instead. Refraction meansthat the wave passes through the interface, and in the processacquiring a di erent direction from the trajectory of the wavethat ﬁrst hit the interface/medium. During refraction, because the wave travels through a medium,naturally, its speed will also decrease. Most electromagnetic
waves travel through the medium at the speed of light, butwhen they are refracted, they travel at a slower speed.