Tuesday, June 22, 2010

They Asked For Some Projects!!!

Here are some projects to try :
PROJECT 1 : Paddle Boat which applies Newton's Third Law
(No volunter yet)

PROJECT 2 : Weird Creatures On Speaker Cone (but who is willing to donate the speaker coz it maybe spoil after used)
Amiruddin & friends already booked this experiment)

PROJECT 3: Magnetic Train (but where can I get the powerful magnet for u, boys?)
(Kaven & Friens booked)

PROJECT 4 : Physics Roller Coaster
(Azmil booked. We try on Monday k! Please stand by another experiment, in case tak jadi)

PROJECT 5 : Can be any interesting projects. As long as the exp related to the syllibus. Can be as simple as rainbow formation or the phenomenon of total internal reflection... Come on boys!!! We are running out of time.

Thursday, June 17, 2010

Can Cellphone Cause Brain Tumor? l by **

This question came when we discussed about the electromagnetic waves which separated into 7 spectrums, Radio, Microwaves, Infrared, Visible, UV, X-ray and Gamma.. So, one students came out with one fact that he heard handphone can cause brain tumor. Which ray used in hp and how does it happen? 
A microwave oven uses microwaves to heat food. Microwaves are radio waves. In the case of microwave ovens, the commonly used radio wave frequency is roughly 2,500 megahertz (2.5 gigahertz). Radio waves in this frequency range have an interesting property: they are absorbed by water, fats and sugars. When they are absorbed they are converted directly into atomic motion - heat. Microwaves in this frequency range have another interesting property: they are not absorbed by most plastics, glass or ceramics. Metal reflects microwaves, which is why metal pans do not work well in a microwave oven.

Many cellular phones have two signal strengths: 0.6 watts and 5 watts (for comparison, most CB radios transmit at 4 watts). The base station is also transmitting at low power.
Microwaves ovens have 500 watts to 1.1k watts.

Below you can see comparison of radiation of cellular phones and microwave ovens:
It may seem that mobile phones cause negligible radiation in comparison to microwave ovens but a simple calculation will show you the opposite.
If you talk on the cellular phone just one hour a day the whole radiation is as follows:

10.000 watts radiation of cellular phone (ten times more powerfull than microwaves ovens) is as if you would put your head in a microwaves oven.You can imagine what would happen to you 
>>> you would burn like a sausage.  

What Causes Cancer (brain tumor)?
Mutations in tumor suppressor genes are another common cause of cancer. As you might expect, a tumor suppressor gene is supposed to prevent tumors. But when these genes are damaged, they can allow cancer to develop instead of preventing it. One of these genes, p53, normally prevents cells with abnormal DNA from surviving. When p53 is defective, these cells with abnormal DNA survive and can multiply, increasing the probability of developing cancer (brain tumor).
Simple image belowe how brain tumor start: 


What is the mechanism of Sailboat? I by Thevan

This question came out when we discussed about the force required to move the sailboat. The more the air trapped, the faster the sailboat moves. So, one of the students was arguing on how the more air will make it moves faster? He thought that the more the air, the more the air resistance produced in opposite direction, thus slows down the sailboat. Hm.. actually, I can not answer that question on the spot. So, I searched for them, so that they can refer at least. ...

How can boats sail faster than the wind? Lots of boats can---especially the eighteen footer skiffs on Sydney Harbour. Ask a sailor how, and he'll say "These boats are so fast that they make their own wind", which is actually true. Ask a physicist, and she'll say that it's just a question of vectors and relative velocities.
Downwind (diagram at left) is easy. If the wind is 10 kt, and the boat makes 6 kt in the same direction, then the crew feels a wind of 4 kt coming over the stern of the boat. The true wind vw equals the speed of the boat vb plus the relative wind vr (see vectors for more explanation). The equation vw = vb + vr tells us the problem: as the boat speed approaches the wind speed, the relative wind drops towards zero and so there is no force on the sail. So you can't go faster than the wind. When the wind is at an angle, we have to add the arrows representing these velocities (vector addition). Upwind (right), exactly the same equation holds: vw = vb + vr.

The faster that the boat goes, the greater the relative wind, the more force there is on the sails, so the greater the force dragging the boat forwards. So the boat accelerates until the drag from the water balances the forward component of the force from the sails.

What is Aurora? l by Shamsul Alam

This beautiful phenomenon happens at the south and north pole of Earth. Auroras, sometimes called the northern and southern (polar) lights or aurorae (singular: aurora) natural light displays in the sky,
  • usually observed at night
  • particularly in the polar regions
  • They typically occur in the ionosphere
  • They are also referred to as polar auroras.
In northern latitudes, the effect is known as the aurora borealis

The aurora borealis is also called the northern polar lights, as it is only visible in the sky from the Northern Hemisphere, with the chance of visibility increasing with proximity to the North Magnetic Pole. (Earth's is currently in the arctic islands of northern Canada.) Auroras seen near the magnetic pole may be high overhead, but from further away, they illuminate the northern horizon as a greenish glow or sometimes a faint red, as if the sun were rising from an unusual direction. The Aurora Borealis most often occurs near the equinoxes. The northern lights have had a number of names throughout history. The Cree call this phenomenon the "Dance of the Spirits."

Its southern counterpart, the aurora australis or the southern polar lights, has similar properties, but is only visible from high southern latitudes in Antarctica, South America, or Australasia. Australis is the Latin word for "of the South."

Auroras can be spotted throughout the world and on other planets. It is most visible closer to the poles due to the longer periods of darkness and the magnetic field.
 [summerized from WIKIPEDIA]

One Malaysian Band, Estranged composed a lyric on Aurora, rite? Is it same with this phenomenon? Lets check it out!