This document discusses different types of waves including mechanical waves, which require a medium, and electromagnetic waves, which can travel through empty space. It describes key wave properties such as amplitude, wavelength, frequency, and speed. It also covers how waves interact through reflection, refraction, diffraction, and interference. The document then focuses on electromagnetic waves, their ability to travel without a medium, and their composition of electric and magnetic fields. It provides examples of different types of electromagnetic waves and discusses theories about the nature of light.

1. Waves
• Wave-any disturbance that transmits
energy through matter or empty space
• Medium – substance through which a
wave can travel (solid, liquid, gas)
• Wave particles vibrate and pass the
energy to a particle next to it
• Mechanical waves must use a medium to
travel (sound, ocean waves)

2. • Electromagnetic waves travel without a
medium or in a vacuum (light waves from
the sun)
• Transverse wave-particles vibrate up and
down (wave travels forward while moving
perpendicular to the forward motion) - all
electromagnetic wave
• Longitudinal wave – moves back and forth
parallel with the direction of the motion

3. • Compression – crowded
• Rarefaction-spread apart
• Properties of Waves:
• Amplitude-related to height, large wave
height more energy
• Wavelength- distance between two crests
or compressions, shorter the wave length
the greater the energy

4. Frequency – number of waves in a given amount of time,
higher the frequency the greater the energy
Wave speed-the speed at which a wave travels through a
medium

5. • Wave interactions:
• Reflection – wave bounces back after hitting a barrier
(sound, light, heat)
• Refraction – bending of light due to a change in medium
and a change in wave speed
• Diffraction-bending of waves around a barrier or
through an opening
• Interference – the combination of two or more waves
that results in a single wave (Ex: resonance – when two
object vibrate at the same frequency)
• Absorption: energy transferred to particles of matter

6. Electromagnetic waves
• Consists of changing electric and
magnetic fields at right angles to each
other and can travel without a medium (in
a vacuum)
• Electric fields surround all electrically
charged objects by vibration which causes
the magnetic field to be created.
• Energy is transferred as radiation

7. • Light travels in a straight line until it strikes
an object is reflected, absorbed or
transmitted
• The speed of light can change depending
on the type of media (matter traveling
through)
• Light is a form of radiant energy that
moves in transverse waves

8. • EM energy from the sun are major source
of energy on earth
• Em spectrum consists of:
• Radio waves, microwaves, infrared, visible
light, ultraviolet, x-ray, and gamma rays,
all move at the speed of light

9. Light theory
• Pythagoras (580-500) – light travels in the
form of tiny particles
• Einstein – EM radiation (light) was a
stream of particles rather than a wave of
energy called photons and that the energy
in the photon was equivalent to the mass
which meant that photons had mass.
E=mc2

10. • Light travels at 300,000,000 m/s through a
vacuum and slightly less through air and
other materials
• 1 light year=9,500,000,000,000 km
• Closest galaxy to ours Andromeda
• 21 quintrillion km or
21,000,000,000,000,000,000 km or
• 2.3 million light years

11. • Closest star Proxima Centauri
• 40,000,000,000,000 km
• EM energy from the sun are major source
of energy on earth

12. Sound
• Sound – energy transmitted through a
medium, type: longitudinal wave
• Composed of compression and rarefaction
waves
• Travel in all directions way from the
source
• Caused by the vibration of an object

13. EM spectrum is arranged from long wavelength to
short or from low frequency to high