Science Class Project
Science
Project
By: Gabriela
Guerra,
Omar Ruiz, Ignacio Acosta & Alejandro Acosta
By: Omar Ruiz, Alejandro Acosta, Gabriela
Guerra & Ignacio Acosta
Lesson 1:
Electromagnetic
Radiation
LESSON 1: ELECTROMAGNETIC RADIATION
• Electromagnetic waves are waves that can travel through
empty space and matter.
• Radiant energy is energy carried by electromagnetic
waves. An electric charge is surrounded by an electric
field. If the charge moves up and down, the field also
moves up and down.
LESSON 1 CONT.
• A changing electric field produces a magnetic field. The
vibration of the charge starts a wave of vibrating electric
and magnetic fields that moves outward in all directions.
•
When the electric field is the strongest in one direction,
the magnetic field is the strongest to that perpendicular
direction.
WAVELENGTH AND FREQUENCY
• Wavelength and frequency: A Wavelength is the distance
between one point on a wave to the nearest point just like
it. Frequency is the number of wavelengths that pass by a
point in a certain period of time.
• Wave speed is its frequency multiplied by its wavelength,
to determine the wavelength divide the speed of light by
frequency of waves.
WAVES CONT.
• Not all electromagnetic waves are visible by the human
eye. Some waves such as ultra violet light reach the
earth and can damage your skin by having a sun burn.
• These waves have greater frequency than other. Other
sources of energy such as a flashlight do not have the
energy to damage your skin. Mechanical waves are
related to its amplitude. A water wave has lots of
amplitude.
THE SUN
• Most of the energy is received from the sun. The sun’s energy is
divided into light, with 44%; infrared, with 49%; and ultraviolet,
with 7%. One type of energy it gives us is thermal energy. Only
a small amount of waves reach Earth.
• Another source of electromagnetic waves is the explosion of
stars. Sources of electromagnetic waves on Earth are
campfires, and light bulbs.
LESSON 2: THE ELECTROMAGNETIC SPECTRUM
• The electromagnetic spectrum is the entire range of electromagnetic
waves with different frequencies and wavelengths.
• There are seven types of electromagnetic waves. One type is a radio
wave, this wave has low frequency and low energy. This electromagnetic
wave has a wavelength of 30 cm, some radio waves have wavelengths
as long as a kilometer or more.
• A microwave is a wave that has low frequency and low energy. These
electromagnetic waves have a wavelength between about 1 mm and 30
cm.
LESSON 2 CONT.
• An infrared wave is electromagnetic waves that have a wavelength
shorter than a microwave but longer than a light.
• Vibrating matter makes infrared waves. Light is electromagnetic waves
that your eyes can see. Red light is has the longest wavelength and the
lowest frequency.
• Violet light has the shortest wavelength and the higher frequency.
ULTRA VIOLET
• An ultra violet wave that has a shorter wavelength and higher
frequency than light can carry enough energy to cause chemical
reactions.
• An x -ray is a high energy wave that has a slightly shorter
wavelength and higher frequency than an ultraviolet wave.
• A gamma ray is a high energy electromagnetic wave with a
shorter wavelength and higher frequency than all the other
electromagnetic waves.
Lesson 3: Using
electromagnetic
waves
LESSON 3: USING ELECTROMAGNETIC WAVES
• Radio waves: Radio waves are obviously the waves that send
out signals for radio shows and television.
• They travel trough air at the speed of electromagnetic waves,
and they don´t harm humans.
• Its wavelenght is long enough to go around many objects.
• Broadcasting is the use of electromagnetic waves to send
information in all directions.
• This became possible when scientists
learned to use radio waves.
CARRIER WAVES
• How do your radio and television receive information to produce
sounds or images?
• Well the answer is simple: carrier waves.
• A carrier wave is an electromagnetic wave that a radio or television
station uses to carry its sound or image signal.
• First the station modulates, or varies, the carrier waves to match
the electrical signal. Then the signal gets converted back into
images or sounds when it reaches your radio or television.
• There are also two ways a station might change a carrier wave.
MODULATION
• Amplitude modulation is the change in the amplitude of a
carrier wave. Meaning it changes the distance a wave carries
from its rest position.
• The other way to change a carrier wave is frequency
modulation, which just like the name says, it´s a change in the
frequency of a carrier wave. A change in frequency matches a
change in sounds or images.
• When a amplitude-modulated wave changes smoothly from high
to low that is known as analog.
DIGITAL SIGNALS
• Digital signals change in steps. For a station to send a digital
signal they have to change some properties of a carrier wave.
•
The station might send the signal as pulses, or a pattern of
starting and stopping. It might even have a code of high and low
amplitudes.
• Sounds and imagines sent by digital waves are usually clearer
than analog signals.
STEP OF BROADCASTING
• The steps of how a radio station broadcasts a signal are the following:
1.
A stations transmitter produces an electric signal to match sounds such as
music or voices.
2.
The station uses the signal to push electric charge up and down an antenna.
This vibrating charge in the antenna produces the radio waves.
3.
A receiving antenna detects waves with a frequency you choose. The radio
waves push electric charge in the antenna, producing an electric current.
4.
Finally a loudspeaker uses the electric current to reproduce the original
sounds.
• Television transmission is similar, but for this, the waves travel trough cables
designed to carry radio waves.
MICROWAVES
• Microwaves are useful for sending and receiving signals, but microwaves
can carry more information than radio waves because their wavelength is
shorter.
• Microwaves can also easily pass trough some, light rain, snow, and clouds.
• Cell phone companies set up small regions of service called cells.
•
Each cell has an antennae where when you make a call you phone send
and receives signals to and from that cell tower.
• For a signal to get to the phone of the
person you called it most pass from
cell to cell until it reaches it.
COMMUNICATION
• Communication with satellites is similar to communication with antennae on
Earth do.
• Transmitters send microwaves signals to the satellites and this signals can
be passed to other satellites or other places on Earth.
• One vary famous use of satellites communication is the Global Positioning
System or as we know it GPS.
• GPS is a worldwide navigation system that uses satellite signals to
determine a receiver´s location.
• At least 24 satellites continually orbit Earth sending different signals.
INFRARED WAVES
• Vibrating molecules in any matter emit infrared waves.
• The wavelength of this waves depends on the object´s temperature. Hotter
objects emit infrared waves with a higher frequency and a shorter
wavelength.
• Infrared imaging happens because of thermal cameras that take pictures by
detecting infrared waves rather than light waves.
• They convert this waves or different temperatures into colors so that your
eyes can interpret the image.
• Scientist launch satellites that detect and photograph infrared waves coming
from Earth.
• This images show vegetation, snowfall, fire smoldering, lava flowing from a
volcano, etc.
LIGHT & ULTRAVIOLET RAYS
• Even though most of the light on Earth comes from the Sun the
one emitted on Earth also has important uses.
• We need electrical lights for businesses, street lights, traffic
signals, movie theaters, some forms of communication, etc.
• Ultraviolet rays can affect your skin if you are too exposed to them,
but they also help kill germs and also some materials glow when
ultraviolet waves strike them.
• Like secret codes on credit cards can be seen with ultraviolet rays
and campers can purify water with ultraviolet rays.
ULTRAVIOLET RAYS
• Ultraviolet rays are also used for medical uses like cleaning tools and
surfaces by bringing them close to ultraviolet lamps.
• Are also used to control or cure certain skin problems like psoriasis. As
the patient is exposed to ultraviolet light several times a week the waves
carry enough energy to slow the growth of the diseased skin cells.
• Also dentist use it to harden an adhesive in just seconds. Without the
ultraviolet light it would take much longer.
• Also flourescents lightbulbs use ultraviolet waves to produce the light.
The chemical absorbs the energy of the ultraviolet waves in the lightbuld
and reemits it as light.
X-RAYS
• X-Rays have even more energy than ultraviolet waves. They don’t only pass the
skin, but also the muscle. This makes them dangerous and useful for medical
imaging and security.
• They are used for security scanning because they can pass trough many
materials except metals. Computers create images of what the X-rays are
scanning.
X RAYS
• For medical detection the x-rays pass trough different soft parts
of your body (can´t pass trough bones). Light parts of the
photographic films show where the bone absorbed the x-rays.
• Now days it exist a computed tomography scanner (CT) that is
a x-ray machine that around a patient, producing a three
dimensional view of the body.
GAMMA RAYS
• Gamma rays have an extremely high energy that can be used to
destroy diseased tissue in a patient.
• They can also be used to diagnose medical conditions.
• Gamma rays are formed when an atoms nucleus breaks apart
or changes.
GAMMA RAYS
• With PET ( Positron Emission Tomography Scan) a detector
monitors the breakdown of a chemical injected into a patient.
• The chemical is attracted to diseased parts of the body. The
detector can see the location of the disease by detecting the
gamma rays emitted by the chemical.
VIDEOS & DEMOSTRATIONS
• http://www.youtube.com/watch?v=cfXzwh3
KadE
CHAPTER SUMMARY LESSON 1
• Electromagnetic waves are waves that can travel through empty
space and matter. These waves carry radiant energy.
• Electric charges are surrounded by electric fields so if the electric
charge moves so does the electric field. When an electric field
moves, it creates a magnetic field that moves in a direction
perpendicular to the electric field.
• Wavelength is the distance between one point and the closest
point just like it.
• Frequency is the number of wavelengths that pass by a point in
a certain amount of time.
CHAPTER SUMMARY LESSON 1 CONT.
Wave speed
Frequency
Wave length
CHAPTER SUMMARY LESSON 2
• A microwave has low frequency and low energy. These
electromagnetic waves have a wavelength between about 1 mm
and 30 cm. Like radio waves, microwaves are used for
communication, such as cell phone signals. With shorter
wavelengths than radio waves, microwaves are less often
scattered by the air.
•
Vibrating matter makes infrared waves.
•
Light is electromagnetic waves that your eyes can see.
• An ultra violet wave has a shorter wavelength and higher
frequency than light and carries enough energy to cause
chemical reactions.
• An x -ray is a high energy wave
• A gamma ray is a high energy electromagnetic wave with a
shorter wavelength and higher frequency than all the other
electromagnetic waves.
CHAPTER SUMMARY LESSON 2
• Lesson 2
CHAPTER SUMMARY LESSON 3
• Radio waves are waves that move at the speed of
electromagnetic waves and don’t harm humans
• Carrier waves are the waves that carry information to your TV or
radio.
• First the station modulates the carrier wave so that it can be
read by your TV. There are two ways a station can do this.
• -Amplitude modulation: change the amplitude of a wave.
CHAPTER SUMMARY LESSON 3 CONT.
• -Amplitude modulation: change the amplitude of a
wave.
CHAPTER SUMMARY LESSON 3 CONT.
• Frequency modulation: changes frequency of wave.
CHAPTER SUMMARY LESSON 3 CONT.
• Digital signals: sometimes a station has to change some
properties and turn it into a pulse.
• In today’s world, electromagnetic waves are at the heart of
everything, the phone you use the light from some light bulbs,
some medical procedures and many more things require
electromagnetic waves. This is why people are scared of solar
flares. Solar flares could disrupt the way electromagnetic waves
behave all around the world and this would basically take away
most of our technology.