Molecules

                                  Molecules

A molecule is defined as a group of two or more atoms arranged in a precise arrangement by means of covalent bonds. A molecule can range in size from two atoms, for example, H 2 (hydrogen), to thousands of atoms in macromolecules such as proteins, nucleic acids or synthetic and natural polymers. It can also occur ionic bonds, hydrogen bonds and other types of chemical bonds between different parts of the molecule, but it is only covalent bonds that are always between atoms in the same molecule.Within the kinetic theory of gases often used the term molecule for all particles in gas regardless of its constituents. According to this definition include noble gases molecules even though they only consist of single unbound atoms. Proteins with quaternary structure consists in fact in many cases by more molecules held together by intermolecular forces, although biochemists often regard them as a single molecule.

                                      Bonding

For a molecule to exist, atoms have to stick together. This happens when two atoms share electrons. Instead of circling just one atom, the electron now circles around two. This is called bonding. The shared electrons are called 'bonds'. Sometimes, more than one electron is shared. The more electrons are shared, the stronger the bond gets and the stronger the atoms stick together. Bonds can also be broken apart. Since most bonds require energy to form, they also give off energy when they are broken. But before most bonds break, the molecule has to be heated. Then the atoms start to move, and when they move too much, the bond breaks. Molecules that require less energy to break than they give off when broken are called fuels. For example, a candle will just sit there and nothing happens. But when you use a match to light it, it will burn for a long time. The match brings the energy to break the first bonds, which release enough energy to break the bonds below them, until the candle has burned down.

I really do hope you found the post informative as well as interesting. Sincerely, William.

Ultrasound

Ultrasound

To understand what ultrasound is and what it’s used for, we must first understand what sound is.

Sound occurs when things vibrate. These vibrations are transferred to the air particles of its surrounding. This causes a chain reaction in the air particle vibrations, causing them to move like waves. These waves are called sound waves and are longitudinal, meaning they travel horizontally. When the sound waves reaches our ears, it vibrates the ear drum. The ear drum sends the vibrations to three small bones that are put together. In this order, they are called the hammer, the     

anvil and the stirrup. This series of bones

amplifies and transports the vibrations

further into the ear, reaching the cochlea. The cochlea transforms the vibrations into electrical impulses which can be understood by the brain. The auditory nerve sends the electrical impulses to the brain.

Sound waves can have different frequencies. A low note has a low frequency and a high note has a high frequency. Frequency means how many waves there are in one second, which we measure in Hz (Hertz). If there is a note with a frequency of 500, there are 500 waves reaching the ear or an oscilloscope in one second. We measure frequency in Hz. Humans can only hear sound between the frequencies of about 27 and 20 000 Hz. A frequency below 27 Hz is called infrasound and a frequency above 20 000 is called ultrasound.

We can’t hear ultrasound or infrasound because our ear isn’t sensitive enough.

Even though we can’t hear ultrasound, it is used to treat many medical issues like looking inside the body(at unborn babies) and breaking down kidney stones. When looking at a fetus you are essentially sending ultrasonic waves towards it using a doppler scanner. The scanner sends out the waves as well as recognizes the changes in the reflected waves as they pass through different tissue. We call the reflected waves echoes. The scanner sends its data to a computer that processes it. The finished image is then shown on a TV screen (images changes as you move the scanner).

Ultrasound scans are much safer and better in some cases than x-rays. Ultrasound scans does not hurt living cells as it's just sound passing through the body. It also gives a better image of soft tissue compared to x-rays which only shows hard organs like bones and tumors. X-rays hurt living cells a lot as it is radioactive rays passing through the body.

- Erik & Leo

Fibre Optics (Total Internal Reflection)

Fibre Optics

Fibre optic cable are a type of cables which works with total internal reflection. Optical fibre is a thin light-pipe. It’s as thin as the human hair and it’s as flexible too. The core is surrounded by cladding which is also made by pure glass. The cladding has a low index which makes the light rays inside the core, totally internal reflected. The edges of the core acts like a mirror and it reflects the right rays through. Outside the cladding, there’s another layer named Buffer Coating (plastic) which protects the cladding and core so they don’t get damaged.

An optic fibre can transfer thousand of phone calls in the same time. A good thing with fibre optics is that they aren’t distracted by electronic or magnetic disorders such as thunders.

The signals used for the internet are electrical so you need a GBIC module because the optical fibre wires use optical signals. The information transmitted is usually digital information generated by computers, telephone systems and cable TV companies. This is a GBIC module (with its cover removed) which is an optical and electrical transceiver/convertor. The electrical connector is at top right, and the optical connectors are at bottom left

Review:

The signals in the optical fibres work with total internal reflection which means that the signal bounces of the surface. It can go on for about 200 km before the signals gets too weak.

The signals from the internet are electrical and the ones in the cable are optical so you need a electrical-optical convertor (GBIC module).

Helpful links and videos:

http://www.youtube.com/watch?v=0MwMkBET_5I

http://en.wikipedia.org/wiki/Fiber-optic_communication

http://www.youtube.com/watch?v=aqazAcE19vw

- Ali

Cordyceps, the real zombievirus

Cordyceps is a parasitic fungi that targets arthropods, mainly insects. There are 400 known species, which only a few have been studied. Ophiocordyceps unilateralis is the one we will focus on. Like most other cordyceps types this fungi takes control over the hosts body. O. Unilateralis targets ants of the species Camponotus leonardi that lives in the rainforests of Africa, South America and Asia.

The fungi penetrates the ants exoskeleton, bypassing host defenses and then progressively takes control of the victims brain. As it enters the ants body it starts to consume less vital tissue of the ants body which causes it to spread rapidly. How it manipulates the host is still unknown but scientist believe it uses enzymes.
After the fungi seizes full control of the host it forces it to climb up the stem of plants, about 25 cm above the unknowing ant colony. It then uses the hosts mandibles to grab onto a leaf, then it kills the host.
Then its fruiting bodies starts growing out of the back of the dead ants head, finally rupturing and releasing spores upon the doomed colony below. This process takes from 4 up to 10 days. This phenomenon is commonly referred to as zombie ants.
But the healthy ants aren't completely helpless as they have learned to recognize an infected ant, as they carry them away from the colony whenever one is spotted.
In the popular post apocalyptic video game The Last Of Us the zombie virus is a mutated version of cordyceps, but there is no need to worry as the chance of it mutating into being able to infect humans is highly unlikely.
 - Erik & Leo

The Polar Zones

The Polar Zones

Polar zones are climate zones furthest from the equator. The Arctic Circle is located at latitude 66.3 ° N and south of latitude 66.3 ° S. The area north of the Arctic Circle called the northern polar zone, and the area south of the Antarctic Circle is called the southern polar zone. There are two polar regions. At the south pole is called the Antarctic area and at the North Pole 's Arctic. The poles are the coldest places on earth. It's so cold that the ground is always frozen and almost all the water is ice. The phenomenon when the ground is frozen all year called permafrost. The cold is due to sun rays from space spread out over a larger area when they hit earth than at e.g. The equator. This is caused out of Earth inclines. Another source of cold is the ice in the polar zones reflects the light back into space.

Climate

In the polar regions, there are two seasons. The winter that takes up two thirds of the year, and the summer, which is much shorter, only about 4 months. During the winter, the soil temperature drops down to -30°C or lower. At the poles, it is an average of 100 mm of precipitation per year. The precipitation is always snow because it's too cold for rain to fall. This leads to low humidity.

In winter, it becomes even very dark, so dark that the sun does not even go up some months. This is called the polar night.

In summer, however, it will be for some time bright all day. This is called the Midnight Sun. But as the sun's rays spread out more at the polar zones, it will not get hot. The temperature is around 0 degrees or lower, but sometimes the temperature goes up to 5 degrees Celsius. In the summer, the ground warms up so much that tolerant plants can live. Grasses, lichens, mosses and shrubs are among the plants that thrive in this climate. But only the upper five feet of ground thaws. Below that is permafrost. It can reach down several hundred meters below the surface.

The People and their Influence

The people who live at the poles are the Sami and Inuit. The Sami people live in the tundra in northern Norway, Sweden, Finland, and an insignificantly small part of Russia. The Sami people live on reindeer herding, fishing and hunting. They have long been nomads who followed the reindeer and lived in their huts, but have begun to settle down more as the new technology is developed. The Inuit are also nomads but they live in Greenland and northern Canada (Baffin Islands). The inuits mainly live on sealfishing.

As the Arctic and Antarctic is so rich of non- found oil resorvoirs, people come there to find oil and wealth. As oil extraction is very dirty, it destroys the environment around it, making life much more difficult for animals and several species are endangered. People's excessive carbon dioxide emissions heat the earth more and more, the so-called greenhouse effect. It gets its name because the atmosphere has about the same effect as a greenhouse, it will hold the heat.

This new, increasing heat causes the ice around the poles to melt and the permafrost declines in some places. Ice that melts makes it more difficult for polar bears and other animals at the poles of life, it affects some species so much that they become endangered.

If the ice at the poles were to melt entirely, sea level would have risen sharply which led to global flooding and low-lying countries and cities had been completely submerged.

To stop these potential natural disasters, all people think about their carbon footprint and the amount of energy they use. You can also donate money to various funds which cares for a better environment.

- Erik

Introduction to our new Blog.

So, as you might've found out already we're going to write a lot about what we learn in class at the Science aswell as Social Science lessons. 

We are 4 guys in school that find Science and Social Science very interesting aswell as important. We will be continuously posting over the semester and we'll probably take a break during the christmas break when we will go hibernating. 

We only use reliable and relevant sources and information e.g. Bitesize and/or books. Our information will be straight forward and not biased.

Here are some rules:

- You are allowed to use the information we post, but we'd appreciate that you do not copy our posts.

- No negative, racist or any kind of offensive comments/posts.

- If you have any questions send to the following E-mail : arssk70@gmail.com

Sincerely, William, Erik, Leo and Ali.