Lesson 1: Introduction to Electromagnetic Waves
Summary
TLDRIn this educational video, Marian Soriano introduces students to electromagnetic waves (EM waves), explaining how they differ from mechanical waves by not requiring a medium to transfer energy. The video covers the formation of EM waves, their characteristics like amplitude, wavelength, and frequency, and the wave equation. It also explores the electromagnetic spectrum, distinguishing between ionizing and non-ionizing radiation, and concludes with an activity to reinforce learning.
Takeaways
- 📱 Electromagnetic waves (EM waves) are used in various technologies such as smartphones, radios, and microwave ovens.
- 🌊 EM waves differ from mechanical waves as they do not require a medium to propagate and can travel through a vacuum.
- 🌀 EM waves are formed by the interaction of electric and magnetic fields, which are perpendicular to each other and to the direction of energy transfer.
- 🔢 The speed of EM waves in a vacuum is a constant, approximately 3 x 10^8 meters per second.
- 🌊 EM waves are transverse waves, with characteristics like amplitude, wavelength, and frequency.
- 📊 Wavelength and frequency are inversely related; as one increases, the other decreases.
- 🔗 The wave equation for EM waves is wave speed = frequency × wavelength.
- 🌈 The electromagnetic spectrum includes a range of EM waves from radio waves to gamma rays, each with different frequencies and wavelengths.
- ⚡ Non-ionizing EM waves like radio waves and visible light have lower energy, while ionizing waves like X-rays and gamma rays have higher energy and are more dangerous.
- 🎨 The energy of photons in EM waves increases with frequency, with gamma rays having the highest energy and shortest wavelength.
Q & A
What are electromagnetic waves?
-Electromagnetic waves, or EM waves, are temporary disturbances that transfer energy from one place to another without requiring a medium. They can travel through air, solid materials, and even a vacuum.
How do electromagnetic waves differ from mechanical waves?
-Electromagnetic waves do not require a medium to propagate, unlike mechanical waves which need a medium like solid, liquid, gas, or plasma to travel through.
What happens when an electric field comes in contact with a magnetic field?
-When an electric field comes in contact with a magnetic field, it forms electromagnetic waves. A changing magnetic field induces an electric field, and vice versa, creating these waves.
What is the constant speed at which electromagnetic waves travel in a vacuum?
-Electromagnetic waves travel at a constant speed of approximately 3 times 10 to the power of 8 meters per second in a vacuum.
What are the characteristics of electromagnetic waves?
-Characteristics of EM waves include amplitude, wavelength, and frequency. Amplitude is the height of a wave, wavelength is the distance between two consecutive crests or troughs, and frequency is the number of waves passing a point in a certain time.
What is the relationship between wavelength and frequency in electromagnetic waves?
-There is an inverse relationship between wavelength and frequency in electromagnetic waves. As one increases, the other decreases.
How can you calculate the frequency of an electromagnetic wave if you know its wavelength?
-You can calculate the frequency of an electromagnetic wave using the wave equation: frequency = speed of light / wavelength.
What is the electromagnetic spectrum?
-The electromagnetic spectrum is a continuum that includes all types of electromagnetic waves arranged according to their frequency and wavelength, ranging from radio waves to gamma rays.
What is the difference between ionizing and non-ionizing radiation?
-Non-ionizing radiation, such as radio waves, microwaves, infrared, visible light, and ultraviolet, does not have enough energy to cause ionization. Ionizing radiation, such as gamma rays and X-rays, has enough energy to ionize atoms and is more dangerous to humans.
How are different types of electromagnetic waves defined?
-Different types of electromagnetic waves are defined by the amount of energy found in their photons. The energy is directly proportional to the frequency of the wave.
What is the order of colors in the visible light spectrum from lowest to highest frequency?
-The order of colors in the visible light spectrum from lowest to highest frequency is red, orange, yellow, green, blue, indigo, and violet.
Outlines
📡 Introduction to Electromagnetic Waves
In this segment, Marian Soriano introduces the topic of electromagnetic waves (EM waves), highlighting their role in everyday activities such as calling on a smartphone, listening to the radio, and using a microwave oven. She explains that EM waves are a form of energy transfer that doesn't require a medium, unlike mechanical waves which need a medium like water or air. The formation of EM waves is described as occurring when an electric field interacts with a magnetic field, creating waves that travel at a constant speed of 3 x 10^8 meters per second in a vacuum. The characteristics of EM waves such as amplitude, wavelength, and frequency are discussed, with examples provided to illustrate the differences between waves with varying frequencies and wavelengths. The segment concludes with a practice exercise for students to determine which wave has a higher frequency and which has a longer wavelength.
🌌 The Electromagnetic Spectrum
This part of the lesson delves into the wave equation for electromagnetic waves, which is wave speed equals frequency times wavelength. An example problem is used to demonstrate how to calculate the frequency of an EM wave given its wavelength. The video then introduces the electromagnetic spectrum, which categorizes EM waves based on their frequencies or wavelengths. The spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. As one moves from left to right across the spectrum, wavelengths decrease while frequencies increase, indicating an inverse relationship between the two. The segment also explains that EM waves can be thought of as streams of massless particles called photons, with each type of EM wave defined by the energy of its photons. The energy of EM waves is directly proportional to their frequency, with higher frequency waves like gamma rays being the most energetic. The distinction between ionizing and non-ionizing radiation is introduced, with ionizing radiation (such as gamma rays and X-rays) being more dangerous to humans due to its higher energy. The video encourages students to draw their own electromagnetic spectrum chart to reinforce their understanding.
🔬 Summary of Electromagnetic Waves
The final paragraph summarizes the key points about electromagnetic waves. It reiterates that EM waves are created by the interaction of electric and magnetic fields and can be described in terms of energy, speed, wavelength, and frequency. The constant speed of EM waves in a vacuum is reiterated as 3 x 10^8 meters per second. The relationship between frequency and wavelength is highlighted, with higher frequencies corresponding to smaller wavelengths. The summary also recaps the types of ionizing and non-ionizing radiation, emphasizing the dangers of ionizing radiation. The electromagnetic spectrum is described as a continuum of all EM waves, ordered by frequency and wavelength, ranging from radio waves to gamma rays. The lesson concludes with Marian Soriano expressing hope that the students enjoyed the lesson and looking forward to the next one.
Mindmap
Keywords
💡Electromagnetic Waves
💡Mechanical Waves
💡Perpendicular
💡Wave Speed
💡Frequency
💡Wavelength
💡Amplitude
💡Electromagnetic Spectrum
💡Ionizing Radiation
💡Non-Ionizing Radiation
💡Photons
Highlights
Electromagnetic waves (EM waves) are used in everyday activities like calling someone on a smartphone, listening to the radio, and cooking with a microwave.
EM waves are a form of energy transfer that does not require a medium, unlike mechanical waves which need a medium like water or air.
EM waves are formed by the interaction of electric and magnetic fields, with the fields being perpendicular to each other and to the direction of energy transfer.
The speed of EM waves in a vacuum is a constant, approximately 3 x 10^8 meters per second, which is the speed of light.
EM waves exhibit characteristics such as amplitude, wavelength, and frequency, which are crucial for understanding their behavior.
Frequency and wavelength are inversely related in EM waves, meaning as one increases, the other decreases.
The wave equation for EM waves is wave speed = frequency x wavelength, which is essential for calculating the properties of different EM waves.
Different types of EM waves include radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays, each with unique frequencies and wavelengths.
The electromagnetic spectrum is a range of frequencies or wavelengths that categorize different types of EM waves.
As you move from left to right on the electromagnetic spectrum, wavelengths decrease and frequencies increase.
EM waves can be described as a stream of massless particles called photons, each carrying a specific amount of energy.
The energy of EM waves is directly proportional to their frequency, with higher frequency waves like gamma rays being the most energetic.
EM waves are classified as either ionizing or non-ionizing radiation, with ionizing waves like X-rays and gamma rays being more dangerous to humans.
Non-ionizing radiation includes radio waves, microwaves, infrared, visible light, and ultraviolet, which do not have enough energy to cause ionization.
An activity is suggested to draw the electromagnetic spectrum and arrange different types of EM waves according to their frequency and wavelength.
The lesson emphasizes that the electromagnetic spectrum is a continuum of all EM waves, arranged by frequency and wavelength.
The summary highlights that EM waves are created by vibrations between electric and magnetic fields and can be expressed in terms of energy, speed, wavelength, or frequency.
Transcripts
[Music]
hello students welcome to great and
science lesson
and i'm your teacher mom marian soriano
[Music]
did you call somebody today using your
smartphone
did you listen to your favorite radio
station
[Music]
or have you tried cooking your food with
a microwave oven
[Music]
did you know that all these human
activities calling someone using your
smartphone
tuning to your favorite radio station
cooking food in a microwave oven
have one all in common they all use
electromagnetic waves or em waves
lesson one introduction to
electromagnetic waves
you have learned from the previous
lessons in science that waves are
temporary disturbance that transfer
energy from one place to another
there are two important ways on how
energy is transported in the world
around us
we have mechanical waves and
electromagnetic waves
what are the differences of these two
remember from your previous lessons in
science waves in water and sound waves
in
air are two examples of mechanical waves
matter such as solid liquid gas
or plasma that mechanical waves are
traveling through
is called a medium
while on the other hand electromagnetic
waves such as visible light differ from
mechanical waves
in that they do not require a medium to
propagate or to transfer
energy this means that electromagnetic
waves can travel not only through air
and solid materials
but also through a vacuum space
how are em waves formed
electromagnetic waves are formed when an
electric field comes in contact with a
magnetic field
[Music]
electricity and magnetism can be static
but changing magnetic field will induce
electric field and vice versa
these changing fields form
electromagnetic waves
always keep in mind that the electric
field and magnetic field of an
electromagnetic wave are perpendicular
or at
right angles to each other remember also
that electric field and magnetic field
are also perpendicular to the direction
of the em wave's energy
always remember that electromagnetic
waves travel with a constant velocity or
speed
of 3 times 10 to the power of 8 meter
per second in vacuum space
em waves are deflected neither by the
electric field nor by the magnetic field
however they are capable of showing
interference or diffraction
em waves are considered to be transverse
waves
to understand further the behavior of em
waves here are some characteristics of
waves that you need to remember
we have the amplitude which is the
height of a wave and usually measured in
meters
remember also that amplitude of a wave
is associated to the amount of energy
a wave is carrying another wave
characteristic
is wavelength which is the distance
between two consecutive grass or trough
and usually measured in meters
next is frequency which is the number of
waves passing a point in a certain time
we normally use a time of 1 second so
this gives frequency the unit hertz
since 1 hertz is equal to 1 wave per
second
let's have practice exercise study these
two waves
which wave has higher frequency
you are correct wave b has higher
frequency than wave a
let's have another one which wave has
longer wavelength
again you are correct wave a has longer
wavelength than wave b
let's continue our lesson
remember also that all electromagnetic
waves travel at the same speed which is
about 3 times 10 to the power of 8 meter
per second
through a vacuum as you further
understand our lesson on em waves please
take note of the following wave equation
electromagnetic waves obey the following
wave formula
this triangulation method will help you
remember the wave equation
which is wave speed is equal to
frequency times wavelength
let's have an example problem using the
wave equation
an em wave has wavelength of 4.0 meters
in a vacuum space
what is the frequency of the em wave
first let's identify the given the given
r
the wavelength which is 4.0 meters and
the speed of light which is 3.0 times 10
to the power of 8 meter per second
we are looking for the frequency of the
em wave
for the equation we will be using the
wave equation
let's have our solution first we need to
derive the equation needed
to find the answer the derived equation
is
frequency is equal to speed of light
over wavelength
now we can substitute the values
the answer is 75 million hertz or 75
megahertz
there are different types of em waves we
have radio waves
microwaves infrared
visible light ultraviolet
x-rays and gamma rays
these em waves can be split into range
of frequencies or wavelength
this is known as the electromagnetic
spectrum
examine the electromagnetic spectrum
chart
starting from radio waves to gamma rays
compare the frequency
and wavelength of em waves
did you notice as you move from left to
right of the electromagnetic spectrum
the wavelengths get smaller and the
frequencies get higher
furthermore there is an inverse
relationship between wavelength and
frequency
which simply means as one goes up the
others goes down
electromagnetic waves can be described
in terms of a stream of massless
particles called photons
it's traveling in a wave-like pattern at
the speed of light
each photon contains a certain amount of
energy
the different types of em waves are
defined by the amount of energy
found in the photons
observe that energy goes up as the
frequency increases
the energy is directly proportional to
the frequency
here is an example radio waves have
photons with low energies
microwave photons have a little more
energy than radio waves
infrared photons have still more
likewise with the order of colors of
visible light they are arranged from
lowest to highest frequency
red has the lowest energy and frequency
while violet has the highest energy and
frequency
lastly we have the most energetic of all
em waves and has the highest frequency
but has the shortest wavelength the
gamma rays
em waves can be classified as ionizing
or non-ionizing form of hydration
non-ionizing radiation is the part of
the electromagnetic spectrum
where there is insufficient energy to
cause ionization
this includes radio waves microwaves
infrared
visible light and ultraviolet
while on the other hand we have the
ionizing radiation
it is a type of energy released by atoms
that travels in the form of
electromagnetic waves
this includes gamma rays or x-rays
ionizing aim waves are more dangerous to
humans than non-ionizing
we'll further discuss about this in our
next lesson
always keep in mind that the
electromagnetic spectrum is a continuum
of all electromagnetic waves
arranged according to frequency and
wavelength
[Music]
let's perform an activity
get a piece of paper a pen and a ruler
you may pause the video as you answer
the activity
[Music]
let's start
[Music]
draw the blank electromagnetic spectrum
chart in your paper
complete the chart by arranging the
different types of em waves
[Music]
let's check your answer
starting from the lowest frequency or
longest wavelength
to the highest frequency or shortest
wavelength
we have range waves followed by
microwaves
we have infrared for the visible colors
of light
we have red orange
yellow green blue
indigo and violet
beyond visible light we have ultraviolet
next we have x-rays and lastly
gamma-ray
[Applause]
to summarize what you have learned
electromagnetic waves or em waves are
waves that are created
as a result of vibrations between an
electric field and a magnetic field
electromagnetic waves can be expressed
in terms of energy
speed wavelength or frequency frequency
is measured
in cycles per second or hertz wavelength
is measured in meters
[Music]
em waves travel with a constant speed of
3 times 10 to the power of 8 meter per
second
in vacuum
the larger the frequency of an em wave
the smaller the wavelength
and vice versa the frequency of an em
wave is directly proportional to energy
you also learn the higher frequencies of
em hydration
consisting of x-rays and gamma rays are
types of ionizing radiation
lower frequency radiation consisting of
ultraviolet or uv
infrared microwaves and radio waves are
types of non-ionizing radiation
the electromagnetic spectrum includes
from longest wavelength to shortness
radio waves microwaves infrared visible
light
ultraviolet x-rays and gamma rays
i hope you enjoyed our lesson this is
mom marian soriano
see you in the next lesson
[Music]
you
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