[Music] hi everyone miss jenning here your grade 7 science teacher for our today science tutorial we will discuss waves its categories types and characteristics are you ready to learn with me let's start it's almost summer time and we want to get rid of the heat some people love to go to the beach to either go swimming or just sit by the seashore and enjoy watching the waves perhaps you also enjoy throwing a stone in water and watch the ripple or waves as it goes bigger and bigger speaking of waves we can also certainly see these waves in a rope or in playing a slinky waves refer to the disturbance that carries energy through material space that moves from one place to another if you tie one end of a rope around a tree and jerk the other end once a disturbance will travel along the rope any wave pulse will be produced a wave pulse is a single disturbance while a wave train is a series of disturbances waves can be classified according to its categories the first one is mechanical wave this wave requires a medium to transfer energy and it can travel through a vacuum examples are sound and ocean waves on the other hand we have electromagnetic wave this wave does not require a medium to transfer energy it can also travel through a vacuum examples are light uv rays and visible light mechanical waves can be classified according to the direction of motion of the particles of the medium [Music] in longitudinal waves the matter in the wave moves back and forth parallel to the direction of the wave [Music] some examples of longitudinal waves are the following a wave in a slinky and a sound wave in a transverse wave the matter in the wave moves up and down at a right angle or perpendicular to the direction of the wave examples of transverse waves are the following rope waves and water wave again this is a difference between a longitudinal wave and a transverse wave [Music] let us now proceed with the characteristic of a transverse wave take note of the following terms first the highest part of a wave is called a crest while the lowest part of a wave is called a trough the height of a crest or depth of a trough measured from the equilibrium position is called the amplitude the distance between a crest to crest or trough the trough is called a wavelength that's it let us have a quick recap [Music] in this video we discuss weebs the categories of waves are the following a mechanical wave which requires a medium to transfer energy and an electromagnetic wave which does not require a medium the types of mechanical waves which are a longitudinal wave and a transverse weave and the characteristics of waves now let's try answering a 5 item quiz about waves you have a minute to answer good luck [Music] do [Music] time's up let's check if your answers are correct [Music] [Applause] that's the end of our science tutorial i hope that you've learned a lot and see you soon thank you for watching