Waves can transfer energy from one location to another without transferring material. There are two main types of waves: transverse waves and longitudinal waves. Transverse waves have vibrations perpendicular to the direction of energy transfer, forming crests and troughs, like water waves and light waves. Longitudinal waves have vibrations parallel to the energy transfer, forming compressions and rarefactions, like sound waves moving through air. Many common phenomena involve different types of waves, such as dropping a rock in water creating transverse waves, using a microwave to heat food via transverse electromagnetic waves, and hearing sounds through longitudinal air pressure waves.

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2. Waves:
What Are They?

3. World of Waves
There are lots of waves all around us in everyday
life.
Sound is a type of wave that moves through matter
and then vibrates our eardrums so we can hear.
Light is a special kind of wave that is made up of
photons that helps us to see.
You can drop a rock into a pond and see waves form
in the water( water waves).
We even use waves (microwaves) to cook our food
really fast.
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What is a wave?
a wave is a rhythmic disturbance that carries
energy through matter or space from one location
to another.
a wave is the motion of a disturbance
a wave transfer Energy from one point to another
without physical transfer of any material between
the two points.

5. Types of waves
• scientists use to classify waves into various
categories depending on their characteristics:

6. Types of waves
What are transverse and longitudinal waves?

7. 1: transverse waves
 Energy travel in a direction
PERPENDICULAR to the direction of the
vibrations.
 consist of a series of crest and trough.
 Examples: water waves, rope waves and
electromagnetic waves (example: light

8. 2: longitudinal waves
 Energy travel in a direction parallel to the direction of
vibrations.
 consist of a series of compressions and rarefactions.
 Example: Sound.

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15. Quiz time
Directions:
• From the next slide answer the question
• You are going to work in 4 teams of 3 students each.
• write T if the statement is true or F if the statement is false.
• If the statement is false, change the underlined word to make it
true. Write your changes on the lines provided.
As The EX:
1- Morad is the tallest one in the class
2- Mohamed is the tallest one in the class
1- T
2- F (Morad )
• Write your answers in one sheet for each group.
• We have 5 minutes to run the activity.
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16. 1. Mechanical waves are waves that move through matter or
empty space.
2. Sound is a mechanical wave travels only through matter.
3. A wave in which the disturbance is perpendicular to the
direction the wave travels is called a longitudinal wave.
4. X-ray an electromagnetic wave can travel through empty
space or through matter.
5. Light is a wave which the energy moves perpendicular to
the direction of the particle movement.
6. A wave in a rope consists of compressions and troughs.
7. transverse waves consist of a series of crests and
rarefactions
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17. Assessment
• For the next session answer this question
(your answer not more than one sheet
Explain How can we differentiate between tow
longitudinal waves or between tow transverse waves . In
other words how can we differentiate between two waves
from the same type.
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18. Thank you
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