Sabado, Disyembre 12, 2015
Lunes, Setyembre 7, 2015
The Electromagnetic Wave (EM wave)
Eduardo C. Gallenero Jr. Grade 10- Prudence
The EM Wave
What is an electromagnetic wave? How it is
produced? What are the types of EM wave? This are the guide questions that we
are going to find out.
Electromagnetic
wave are waves which can travel through the vacuum of outer space. Mechanical
waves, unlike electromagnetic waves, require the presence of material medium in
order to transport their energy from one location to another.
Electromagnetic radiation consists of
electromagnetic waves, which are synchronized oscillations of electric and
magnetic fields that propagate at the speed of light. The oscillations of the
two fields are perpendicular to each other and perpendicular to the direction
of energy and wave propagation, forming a transverse wave. Electromagnetic
waves can be characterized by either the
frequency or wavelength of their oscillations to form the electromagnetic
spectrum, which includes, in order of increasing frequency and decreasing the
wavelength: radio waves, microwaves, infrared radiations, visible light,
ultraviolet radiation, X-rays, and gamma rays. Electromagnetic waves are
produced whenever charged particles are accelerated, and these waves can
subsequently interact with any charged particles. EM waves carry energy,
momentum and angular momentum away from their source particle and can impart
those quantities to matter with which they interact. A charged particle
produces an electric field. The electric field exerts a force charged particles. Positive charges
accelerate in the direction of the field and negative charges accelerate in the
direction of the field and negative charges accelerate in a direction opposite
to the direction of the field. Also a moving charged particle produces a
magnetic field. This field exerts a force on other moving charges. The force on
those charges is always perpendicular to the direction of their velocity and
therefore only changes the direction of velocity. Since electromagnetic waves
are electric and magnetic field traveling through empty space at the speed of
light, then an accelerating charged particle produces an electromagnetic wave.
The
types of EM wave are the radio waves, microwaves, infrared, visible light,
ultraviolet radiation, x-rays, gamma rays. Radio waves have the longest
wavelengths in the electromagnetic spectrum. These waves can be longer than a
football field or as short as football. Radio is used primarily for
communications including voice, data and entertainment media. Microwaves fall in the range of
the EM spectrum between radio and IR. They have frequencies from about 3 GHz up
to about 30 trillion hertz, or 30 terahertz (THz), and wavelengths of about 10
mm (0.4 inches) to 100 micrometers or 0.004 inches. Microwaves are used for
high-bandwidth communications, radar and as a heat source for microwave ovens
and industrial applications. Infrared (IR) is invisible radiant energy,
electromagnetic radiation with longer wavelengths than those of visible light,
extending fro the nominal red edge of the visible spectrum at 700 nanometers
(frequency 430 THz) to 1 mm (300 GHz). The most common use of infrared in
everyday life is remote controls. These work by sending pulses of infrared that
spell out a message to an electronic device. Infrared can be used in a similar
way for communication. Thermal imaging cameras use infrared to look at
human body heat emissions, both for medical purposes and in night-vision
cameras. Visible light waves are the only electromagnetic waves we can see. We
see these waves as the colors of the rainbow. Each color has different
wavelength. Red has the longest wavelength and violet has the shortest
wavelength. When all the waves are seen together, they make white light. We
concentrate visible light to make lasers to use in everything from
surgery, to CD players to laser pointers. Visible light waves also
make our TV, computer and cell phone screens work. Ultraviolet light is an
electromagnetic radiation with a wavelength from 400 nm to 100 nm,
shorter than that of visible light but longer than X-rays. It can be used to
confirm the validity of banknotes and identity cards. Suitable doses
of Ultraviolet rays cause the body to produce vitamin D, and this
is used by doctors to treat vitamin D deficiency and some skin
disorders. X-rays an electromagnetic wave of high energy and very short
wavelength which is able to pass through many materials opaque to light. The
most familiar use of x-rays is checking for broken bones. Gamma-rays have the smallest
wavelengths and the most energy of any other wave in the electromagnetic
spectrum. These waves are generated by radioactive atoms and in nuclear
explosions. Gamma-rays can kill living cells, a fact which medicine uses to its
advantage, using gamma-rays to kill cancerous cells. Depending on the energy, nearly
all of them, but generally, the higher the frequency, the more dangerous. UV,
X-Rays, and Gamma radiation are all generally harmful. Starting with the most
obviously dangerous, gamma rays are the highest frequency and most energetic
form of light. They penetrate the human body and cause radiation poisoning after
nuclear events like melt downs. Very harmful. X-Rays penetrate skin and muscle
but not bones. They're useful for medical and dental imaging, but if they
interact with your DNA, they can cause cancer. In fact, the first people to die
because of X-rays were shoe salesmen. They used an x-ray device to scan
people's feet and were overexposed to harmful x-rays.
UV rays can interact with your skin and your eyes. They cause you to tan, get a
sunburn, or get skin cancer. Their wavelength allows them to penetrate the top
layers of your skin, and if they interact with your skin cells, they can
develop cancer.
To avoid the harmful effects of EM waves
is that to follow this following ways like cooking and eating without using
microwaves. You can simply heat things up in a conventional oven or a toaster
oven, or just get used to eating cold leftovers! In fact, many people find that
food tastes better and has a better texture when heated in the oven instead of
a microwave, so saving yourself from harmful radiation might have some other
added benefits! The second, people most commonly used laptop and computer in
the way of communications. The
good news is you don’t actually have to give up your laptop to protect
yourself. There are now devices like The DefenderPad that
shield you from the negative health issues related to laptop Electromagnetic
Radiation. Denying the harmful effects of Electromagnetic Radiation won’t make
you immune to them. Your best bet is to educate yourself and find ways to
protect yourself.
BIBLIOGRAPHY:
by Jim Lucas, Live Science
Contributor
Miyerkules, Agosto 5, 2015
Miyerkules, Hulyo 22, 2015
The Pacific Ring of Fire(essay)
The Pacific Ring of Fire
What is
Pacific Ring of Fire? What is in there? How volcanoes are formed? This are the
guide questions that we want to find out.
The Pacific Ring of Fire is the boundaries of the Pacific
plate where we can see many active volcanoes. The Pacific plate is the largest
tectonic plate on Earth. Almost oceanic plate, it is subducted underneath large
and small continental plates that surround it. As the edges of the Pacific
plate scrape and collide against continental plates during subduction,
volcanoes, deep ocean trenches, mountain ranges formed. Also the Pacific Ring
of Fire is susceptible to and very much frequented by volcanism-related
geological activities such as volcanic eruptions, earthquakes, faulting, and
tsunamis among others. It is where more than half of the world’s volcanoes are
found. Volcanic activity, such as eruptions and the crustal movements around
the Pacific plate, have caused massive seismic activities. There are such
happened in the Pacific Ring of Fire like eruptions of volcanoes, and followed
by several earthquakes that almost people who lived in the Pacific might
experienced. During volcanic eruptions can cause many people died and faced
different difficulties like crisis of food, things they need and others. Not only
volcanic eruptions can cause of death but also followed by an earthquake that
caused of destruction and destroyed of things and buildings that may affect the
lives of the people. Earthquake refers to the shaking of the Earth as a result
of breaking and shifting of the rocks of the tectonic plates, which release
seismic energy. Majority of earthquakes occurred along the boundaries of
tectonic plates, which collide, push each other, or slide past each other.
Earthquakes occur because of the pressure underneath the earth’s crust that
pushes blocks of rocks to move along fault lines. When we talk about the
formation of the volcano, volcanoes are formed because of the massive friction
occurred to the two massive plates that released enough energy that makes the
rocks melt. The melted rocks due of the massive friction formed into magma that
goes up to escape on the Earth surface that eventually seek a vent. Due of
continues subduction, it gives high internal heat the reason why magma push up
to reach the Earth surface. Volcanoes formed in subduction zones. In other
words, subduction happens during the subduction of the oceanic and continental
plate, the oceanic plate goes down. As the denser oceanic plate subducts
beneath the continental plate and descends into the mantle that gives
temperature increases causing the rocks to melt. The same mechanism also may
occur between two oceanic plates with different densities that the denser plate
subducts beneath the another. Such activity may result in the formation of
underwater volcanoes. The volcanic debris from the eruption of underwater
volcanoes pile up until an island volcano rises above level. In other theory,
volcanoes are formed because there are hot spots that rocks rises up causing
the formation of volcanoes.
In summary,
we know already what is the Pacific Ring of Fire, it is the boundaries of the
Pacific plate where we can see many active volcanoes and also with the
formation of the volcanoes because of subduction. In that such activities, we
should put in mind that we are also located in the Pacific ring of Fire and we
must know what to do and how to handle this. In order for us to get ready in
this earthquake activity, we should know what to do. It’s always important to
be calm and alert during an earthquake. One should know the safest spot to stay
and the easiest to escape route to minimize or avoid accidents or further
damage. That’s the relation about living in the Pacific Ring of Fire and how
volcanic activities can affect into the lives of the people.
Sabado, Hulyo 4, 2015
Top 10 Most Dangerous Active Volcanoes
1.Mount Fuji, Japan
One of the most famous peaks on the planet, Mount Fuji is a potent
symbol of Japan. Scaling its heights is a national must-do. Although
still classed as active, Fuji hasn’t erupted since 1708, so the threat
of being consumed by hot magma is thankfully fairly low..
2.Mount Bromo, IndonesiaIndonesia does quite well for volcanoes, if it's right to put it like that. Ijen, Ranjani, Semeru, Kelimutu and many more. Mount Bromo is but one in a series of peaks in East Java, sitting in the middle of the evocatively-named Sea of Sand. Bromo went bang big style in 2011.
3.Popocatepetl, Mexico
Try saying that after a few mezcals. Looming over Mexico City (if
the smog thins enough to see it), Popocatepetl provides an anxious
presence. With increasing activity, including several eruptions of steam
and ash just last month, it is looking odds-on for a big blow in the
near future.
4.Mt. Kilauea, Hawaii
Kilauea on Hawaii’s Big Island claims the title of the world’s most
active volcano. Take a boat trip to see one of its most spectacular
sights – red hot lava oozing into the ocean which causes the sea to boil
and vaporise into white plumes of steam.
5.Sakurajima, JapanThis composite volcano in Japan was once its own island, but lava flows in its 1914 eruption caused it to connect to the mainland. Many experts refer to it as the “Vesuvius of the east”, due to its high level of volcanic activity.
Every year, thousands of small explosions come from Sakurajima’s peak, throwing up ash over the surrounding areas. However, a major eruption could have deadly consequences for the 700,000 residents of Kagoshima, who live just miles from the Volcano. The city even has special volcano shelters where people can go to take cover from falling debris.
6.Galeras, ColumbiaLocated in Southern Columbia near the border with Ecuador, Galeras has been active for at least 1 million years. It erupts frequently, with its first recorded eruption dating back to 1580. More alarming is the fact that a city of 450,000 residents – the city of Pasto – lies on its eastern slope.
While it went dormant in 1978, it went active again in 1988 after just 10 years. When scientists held a Decade Volcano conference in 1993 to address the dangers of Galeras, an unexpected eruption occurred, killing 6 scientists and 3 tourists. Since 2000, it has erupted almost every year, spouting out ash and lava and causing tremors in the region.
7.Mt. Merapi, Indonesia
Mt. Nyiragongo is one of the most active volcanoes on the African continent. It’s well known for its large lava lakes, which frequently appear in its crater. Nyiragongo poses a unique threat to surrounding communities, as nowhere in the world does a steep sided stratovolcano carry such a large lake of fluid lava.
In fact, from 1894 to 1977, Nyiragongo’s summit crater was filled with a large, active lava lake. When the walls of the crater fractured on Jan 10, 1977, the lava lake drained within an hour, causing massive lava flows of over 60 miles per hour. These flows quickly overwhelmed local villages, causing several thousand people.
The Taal Volcano is a cinder cone volcano. It is located on the island of Luzon, Philippines where it lies at the middle of Lake Taal. It lies just 31 miles from Manila – the capital of the Philippines and home to 1.6 million people.
The Taal Volcano has had 33 recorded eruptions since 1572. While most of these eruptions are confined to the intracaldera area, some eruptions devastate the entire region with its fallout. Altogether, it’s estimated that 5,000-6,000 people have been killed by eruptions at Taal. Even today, the only safe way to view the active Taal Volcano is from a safe distance. Of course, that doesn’t stop adventurers from trekking on “Volcano Island”.
9.Mauna Loa, Hawaii
In terms of volume and surface area, Mauna Loa is the largest volcano in the world. It is also one of the 5 volcanoes that make up the Island of Hawaii, all the way in the middle of the Pacific Ocean.
Mauna Loa has been erupting regularly for at least the past 700,000 years, with its most recent eruption occurring in 1984. The most significant hazard Mauna Loa poses to surrounding communities are its lava flows. Although most of the flows from Mauna Loa advance at a slow pace, posing little danger to human life, major eruptions can cause fast moving flows. In 1950 for example, the village of Ho’okena Mauka was destroyed by flowing lava. The intense 1984 eruption saw lava flows that moved towards the highly populated Hilo, but didn’t reach any buildings.
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Ulawun, Papua New Guinea
- See more at: http://ohtopten.com/top-10-most-dangerous-volcanoes/#sthash.LtHpJFjF.dpuf
The first recorded eruption of Ulawun was in 1700. Several thousand people live near the volcano.There have been 22 recorded eruptions since the 1700s. The last few years have seen almost constant activity at Ulawun, with frequent small explosions. Eruptions originate from a central crater. Its eruptions devastated the NW flank of Ulawun and modified the summit crater. An eruption in 1980 ejected ash to 60,000 ft and produced pyroclastic flows which swept all flanks of the volcano and devastated an area of 20 sq km. The most serious volcanic hazard at Ulawun volcano is catastrophic structural collapse, producing an eruption which could devastate hundreds of sq km in area.
Ulawun volcano is 400 m higher than most of the volcanoes in the Bismarck which indicates it may be at the limit of structural stability. Seismic activity remained high at Ulawun Volcano in 2008. A magnitude 5.1 earthquake hit 10 km west of Ulawun volcano on 28th May 2009. On 14-15 February 2010 ash emissions from Ulawun volcano reached a height of 3.7 km and drifted 95 km.
Ulawun
is such a dangerous volcano which started erupting from 18th century.
Because of dangerous volcanic eruption in year 1980, its ashes ejected
upto 18 kms and destroyed an area of 20 square kms. It’s the dangerous
volcano which having the highest peak in Papua New Guinea. This
dangerous volcano was lastly erupted in year 2010, whose ashes emitted
upto 3.7 kms. - See more at:
http://ohtopten.com/top-10-most-dangerous-volcanoes/#sthash.LtHpJFjF.dpuf
Ulawun, Papua New Guinea
Ulawun, Papua New Guinea
Ulawun
is such a dangerous volcano which started erupting from 18th century.
Because of dangerous volcanic eruption in year 1980, its ashes ejected
upto 18 kms and destroyed an area of 20 square kms. It’s the dangerous
volcano which having the highest peak in Papua New Guinea. This
dangerous volcano was lastly erupted in year 2010, whose ashes emitted
upto 3.7 kms. - See more at:
http://ohtopten.com/top-10-most-dangerous-volcanoes/#sthash.LtHpJFjF.dpuf
Ulawun, Papua New Guinea
- See more at: http://ohtopten.com/top-10-most-dangerous-volcanoes/#sthash.LtHpJFjF.dpuf
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