Gamma Rays

http://www.wix.com/moraphis/scijournalpranavi#!gamma-rays

Kieren and Matthew Mircowaves

Microwaves - Matthew and Kieren

Microwaves

Microwaves range frm one millimeter to a meter,hence the term micro which is 10 to the power of -3.These type of waves vibrate fat and water molecules inside and outside of the object thus making the object hot and free of germs
Uses
Mircowaves are used for 3 things.Cooking,telecommunications and speed cameras are some of them.The microwaves heat up the particles in the food,usually fat or water and thus makes them very hot.
Microwaves are also used in phones and they give out a mircowave signal and this go to the radar dishes.Since the mircowave signal from the phone is weak,multiple radar dishes must be set up so as to recieve the signals which may cost some money
Microwaves are also used in speed cameras where they are used to bounce off moving cars to measure the speed of the cars and if the car is moving too fast they snap a picture of the liscence plate

DAngers

It may cause people to cause some brain damage to themselves due to the phones being to near their heads

Radiowaves - Alpha Vivek Kun Yao

Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be as long as a football field. Instead of only bring music to you radio radio waves have other different uses. They also carry signals for your television and cellular phones.

Radio telescopes ,which emits or detect and reads radio waves, look at planets and comets, giant clouds of gas and dust, and stars and galaxies. By studying the radio waves originating from these sources, astronomers can learn about their composition, structure, and motion.

Radio waves are believed to cause cancer, leukaemia and other disorders.

Radio waves are usually produced by electric current alternating at radio frequency flowing in a special purpose conductor, called an antenna. Antenna dimensions must generally be comparable to wavelength to work efficiently. Very long waves are not practical because of the enormous antennas needed to produce them, although they are sometimes produced by lightning. Radio waves are also produced by cosmic phenomena in deep space. Actually, any kind of reciprocating motion of electric charges or magnets can produce radio waves if it is fast enough. Although very impractical, even a person waving a charged stick very fast can produce faint radio waves.

Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can be longer than a football field or as short as a football. Radio waves bring music to your radio and carry signals for your television and cellular phones.

The antennae on your television set receive the signal, in the form of electromagnetic waves, that is broadcasted from the television station. It is displayed on your television screen.

Cable companies have antennae or dishes which receive waves broadcasted from your local TV stations. The signal is then sent through a cable to your house.

How do we "see" using Radio Waves?

Objects in space, such as planets and comets, giant clouds of gas and dust, and stars and galaxies, emit light at many different wavelengths. Some of the light they emit has very large wavelengths - sometimes as long as a mile!. These long waves are in the radio region of the electromagnetic spectrum.

Investigating Electromagnetic Spectrum

Split into 7 groups. Each group will investigate further on each of the electromagnetic wave. Post your finding in the blog.


Title of your post

EM Wave that your group is investigating

Body
- Summarize your findings.
- Include at least one usage and/or one danger of the EM Waves your are investigating

Resources

http://science.hq.nasa.gov/kids/imagers/ems/index.html
http://school.discoveryeducation.com/lessonplans/interact/electromagneticspectrum.html
http://missionscience.nasa.gov/ems/01_intro.html
http://www.darvill.clara.net/emag/index.htm
http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/radiation/the_electromagnetic_spectrumact.shtml

What affects the speed of waves? (Pranavi, Catherine and Samuel)

Link to site: http://www.wix.com/moraphis/scijournalpranavi#!ws-1-example-3

Link for Gamma Rays :http://www.wix.com/moraphis/scijournalpranavi#!gamma-rays

Tension only affects the height of the wave, not the speed.


Amplitude only affects the maximum displacement of the graph.

Wave Speed - Alpha and Adam

Amplitude

Amplitude does not affect the speed of the wave as it only changes the displacement of the wave.Tension

Tension does not affect the speed of the wave as it only increases the amount of force applied on the waveFrequency

Frequency does not change the speed of the wave.

What affects the speed of waves? -Matthew, Mohit, Kenneth

Below is the control of the experiment (Fig 1.1). Subsequently, there are another 3 more diagrams with one variable changed for each experiment. (Fig 1.2, 1.3, 1.4)

Fig 1.1: The control. The control has a high tension, an amplitude of 50, a frequency of 50 and no damping is applied.Fig 1.2: Variable changed: tension. This setup has medium tension, an amplitude of 50, a frequency of 50 and no damping is applied. However, changing the tension of a medium (or string) would mean that the entire experimental setup would be different. However, a medium of a lower tension would let the wave travel faster through the medium.

Fig 1.3: Variable changed: Amplitude. This setup has high tension, an amplitude of 25, a frequency of 50 and no damping is applied. The amplitude determines the height of the wavelength, and the speed of the wave does not change. This is evident in Fig 1.3.

Fig 1.4: Variable changed: Frequency. This setup has high tension, an amplitude of 50, a frequency of 14 and no damping is applied. The frequency determines the number of waves per second but the speed of the wave does not change. This is evident in Fig 1.4.

X-Rays - Adam, Abigail & Wu Shen

X-rays carry a lot of energy and are high frequency waves.
X-rays have very small wavelengths, between 0.03 and 3 nanometers, so small that some x-rays are no bigger than a single atom of many elements. It passes through most substances making it useful in medicine and industry to see inside things.
X-rays are given off by exploding stars like novae and supernovae and black holes, and also stars. They are emitted when an electron moves from certain excited states back down to its ground states, or when an electron that is moving very quickly is suddenly stopped.

Uses
They are used by doctors to see inside people because it can pass through soft tissues but not easily through bones.
They are also used in airport security checks to see the items in your luggage.
They are also used by astronomers to detect objects in the universe that emit x-rays using a radio telescope.

Dangers
An overdose exposure of X-rays may produce cancer, skin burns and a reduction of the blood supply

Sources
http://school.discoveryeducation.com/lessonplans/interact/electromagneticspectrum.html
http://www.darvill.clara.net/emag/index.htm

Ultra Violet Rays - Amrit, Zhixiang, Mohit

We learnt that

• Sunlight consists of 2 types of light waves or radiation; visible and invisible. Visible light has a spectrum of 7 colors ranging from red to violet. Invisible ultraviolet (UV) radiation is not possible for detection to the human eye, e.g. infrared and X-rays. UV radiation is further divided into 3 different types – UVC, UCB and UVA. 
• The very toxic UVC is filtered out by the ozone layer. The ozone layer also filters UVB but about 1% of UVB still passes through to reach earth. UVB is what causes sunburn and even skin cancers after prolong exposure. 
  
• Whether the weather is windy, cloudy or foggy during the day, harmful UV rays are still able to penetrate through. 

Visible Light - Mirza, Zhi Yong and Jonathan

Visible white light is actually made up of a whole range of colours. It is the portion of the electromagnetic spectrum that is visible by the human eye. When is passes through a glass prism, the light is separated into 7 colours and this process is called dispersion. The colours are red, orange, yellow, green, blue, indigo and violet. The red colour, Infrared, has the longest wavelength, and the violet, UltraViolet, has the shortest wavelength. The sun is a natural source of visible light.

The uses of Light: Light allows us to see objects. Different objects absorb certain light and reflect away the other colours. Thus different objects have different colours. The colour of the objects is determined by what light is absorbed and what light is reflected back to our eyes.

Dangers : Too much light can damage the retina in your eye. This happens when you look at something which is very bright. One such example is the sun. Although the damage can heal, there are some cases where the situation is very bad. It will be permanent if you stare at the light for too long.

Sources:

http://www.darvill.clara.net/emag/emagvis.htm

http://science.hq.nasa.gov/kids/imagers/ems/roygbiv_waves.gif

Infra-Red - Elijah And Kenneth

Our Findings

The reason why Infrared waves are called infra red waves its because the frequency is just below visible red light.

Infrared light gives off heat.

Uses and Dangers

A Picture of Infrared Camera (Thermal Imaging)

Credit: NASA/JPL-Caltech
The users are used for remote controls for TVs and video recorders, and physiotherapists use heat lamps to help heal sports injuries. Also, they are used night-vision goggles or infrared cameras allow us to detect the infrared waves emitting from warm objects such as humans and animals.

The danger to people from too much Infra-Red radiation is overheating.

Sources 

http://www.darvill.clara.net/emag/emaginfra.htm

What affects Speed of waves - Daniel & Wu Shen

The following shows the speed of waves at different frequencies:


The following shows the speed of waves at different Amplitudes:


The following shows the speed of waves at different tensions:

What affects the speed of waves.

This shows the comparison on how the frequency does not affect the speed of waves. As you can see in the picture, when you increase or decrease the frequency, it changes the number of waves per second. If it is increased, the number of waves per second is more than when you decrease. Even though this is correct, it does not affect the speed of the wave.

Tension does affect the speed of waves. By changing the tension, it affected the graph or rather the speed. Compared to the normal screenshot, the time taken for this wave to reach the end is longer.

Amplitude does not affect the speed of waves. When the amplitude of the wave changes, the only sign of change is in the height of the wave. So, even if you change the wave the time taken for the wave to reach the end is the same. It is seen clearly in the screenshot that the time taken is still 1.69s.

Done By: Muhd Mirza, Benjamin Tan Zhi Yong and Jonathan Then

Worksheet 1 General Properties of Waves [Example 3] -Vivek Kun Yao

What affects the speed of the Wave?

With the following pictures, we can prove if speed changes if we either change the frequency or the amplitude. Here is a picture of our control.

Control:

Above is a picture of the control when both the Amplitude and the

Frequency is at 50.

Frequency Increased:

Above is a picture of what happens if we changed the Frequency to 100. W

e have also calculated the time of a full cycle.

Amplitude Increased:

Above is a picture of what happens when we increase the Amplitude to 1

00 and decrease the Frequency back to 50. We also calculated the timing of a full cycle.

Tension Changed:

Finally, this is a screenshot of what happens when we changed the tension. The time taken for a complete wave is 55 seconds.

Over here we shall calculate the speed of the wave when either the amplitude or the frequency has increase.

Speed of Control.

Speed = Distance/Time

= 90/55

= 1.636

= 1.64 cm/s (3 s.f.)

Speed when Amplitude is changed.

Speed = Distance/Time

= 90/55

= 1.636

= 1.64 cm/s (3 s.f.)

Speed when Frequency is changed.

Speed = Distance/Time

= 90/27

= 3.333

= 3.33 cm/s (3 s.f.)

Speed when Tension changed.

Speed = Distance/Time

= 90/55

= 1.636

= 1.64 cm/s (3 s.f.)

Control:

90cm/timetaken

Higher Frequency:

90cm/timetaken

When the frequency is higher than 50 the speed changes as the wavelength of the wave changes. This affects the speed too. This shows that when there is a higher frequency the speed of the wave changes.

Control:

90cm/timetaken

Higher Amplitude:

90cm/timetaken

When the amplitude changes it changes in the why direction so the time taken and the wavelength or period do not get affected, thus the speed of the wave is still the same.

Control:

90cm/timetaken

Lower Tension:

90cm/timetaken

When the tension is lower the wave moves through the string in the same speed as when the tension is higher. Thus, the elasticity does not help the wave move easier. This results in the same speed when the wave is on a less elastic speed compared to a more elastic speed.

Vivek

Kun Yao

S2-05