To all:
The deadline for Part 1 of the project is over.
Some of you have sent your files in 07 format. Do give me some time to access as currently my laptop cant open them. need to use another computer to open that.
So dont worry about that.
Some of you have not followed my instructions. No acknowledgments, incorrect length of reflection. Some just copied wholesale from the website without understanding fully wat was being written. Some just took from the textbook which was really short. Marks would be deducted accordingly if so.
Late submissions from now onwards will result in loss of marks except for those who have approached me personally due to valid reasons. No submissions will cause a ZERO MARK to be awarded.
Note: some of your pics arent uploaded in the blog. But pls make use of them when you get together in your groups to design the poster. Thanks
A gentle reminder: This project will be counted as a CA mark in Term 3. No submission or late submission will result in YOU getting 0 marks in Term 3. TAKE NOTE!
Friday, June 20, 2008
Refraction of Light by 2E2 Chen Jing
!what do you learn about that particular topic?
I learn that the The bending of light that occurs when light passes from one transparent material to another is called refraction of light.light bends because its speed hanges as it moves from one transparent material to another.
light travels slower in more dense materials than in less dense materials.therefore light travels slower in glass than in air.
and i know many effects of refraction of light.such as we can use refraction of light to made the words appear to be nearer to the surface of the glass than they actually are.
From:textbook resource!
summarise the key points of that topic.
Refraction is the bending of light that takes place at a boundary between two materials having different indices of refraction.
Refraction is due to a change in the speed of light as it passes from one medium to another. The change in direction of the ray (represented by the heavy line in each diagram) is what is meant by the term refraction, which just means ¡°bending¡± or ¡°breaking.¡±
From:http://mintaka.sdsu.edu/GF/explain/optics/refr.html!
anything interesting to add?I
n 1621, a Dutch physicist named Willebrord Snell (1591-1626), derived the relationship between the different angles of light as it passes from one transperent medium to another.
When light passes from one transparent medium to another, it bends according to Snell's law which states:Ni * Sin(Ai) = Nr * Sin(Ar),
where:Ni is the refractive index of the medium the light is leaving,Ai is the incident angle between the light ray and the normal to the meduim to medium interface,Nr is the refractive index of the medium the light is entering,Ar is the refractive angle between the light ray and the normal to the meduim to medium interface.
From:http://www.ps.missouri.edu/rickspage/refract/refraction.html
I learn that the The bending of light that occurs when light passes from one transparent material to another is called refraction of light.light bends because its speed hanges as it moves from one transparent material to another.
light travels slower in more dense materials than in less dense materials.therefore light travels slower in glass than in air.
and i know many effects of refraction of light.such as we can use refraction of light to made the words appear to be nearer to the surface of the glass than they actually are.
From:textbook resource!
summarise the key points of that topic.
Refraction is the bending of light that takes place at a boundary between two materials having different indices of refraction.
Refraction is due to a change in the speed of light as it passes from one medium to another. The change in direction of the ray (represented by the heavy line in each diagram) is what is meant by the term refraction, which just means ¡°bending¡± or ¡°breaking.¡±
From:http://mintaka.sdsu.edu/GF/explain/optics/refr.html!
anything interesting to add?I
n 1621, a Dutch physicist named Willebrord Snell (1591-1626), derived the relationship between the different angles of light as it passes from one transperent medium to another.
When light passes from one transparent medium to another, it bends according to Snell's law which states:Ni * Sin(Ai) = Nr * Sin(Ar),
where:Ni is the refractive index of the medium the light is leaving,Ai is the incident angle between the light ray and the normal to the meduim to medium interface,Nr is the refractive index of the medium the light is entering,Ar is the refractive angle between the light ray and the normal to the meduim to medium interface.
From:http://www.ps.missouri.edu/rickspage/refract/refraction.html
Refraction of Light by 2E2 Tan Chew Mei
i.What is refraction of light ?
Refraction is the change in direction of a wave due to a change in its speed. This is most commonly seen when a wave passes from one medium to another. Refraction of light is the most commonly seen example, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is also described by Snell’s Law.
ii.When does it happen? How will light bend ?
In optics, refraction occurs when light waves travel from a medium with a given refractive index to a medium with another. At the boundary between the media, the wave's phase velocity is altered, it changes direction, and its wave length increases or decreases but its frequency remains constant. For example, a light ray will refract as it enters and leaves glass; understanding of this concept led to the invention of lenses and the refracting telescope.
iii. What is refractive index ?
Refraction can be seen when looking into a bowl of water. Air has a refractive index of about 1.0003, and water has a refractive index of about 1.33.
Iv. Effect of refraction ?
refraction can make objects appear closer than they are, it is responsible for allowing water to magnify objects. First, as light is entering a drop of water, it slows down. If the water's surface is not flat, then the light will be bent into a new path. This round shape will bend the light outwards and as it spreads out, the image you see gets larger.
Refraction is the change in direction of a wave due to a change in its speed. This is most commonly seen when a wave passes from one medium to another. Refraction of light is the most commonly seen example, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is also described by Snell’s Law.
ii.When does it happen? How will light bend ?
In optics, refraction occurs when light waves travel from a medium with a given refractive index to a medium with another. At the boundary between the media, the wave's phase velocity is altered, it changes direction, and its wave length increases or decreases but its frequency remains constant. For example, a light ray will refract as it enters and leaves glass; understanding of this concept led to the invention of lenses and the refracting telescope.
iii. What is refractive index ?
Refraction can be seen when looking into a bowl of water. Air has a refractive index of about 1.0003, and water has a refractive index of about 1.33.
Iv. Effect of refraction ?
refraction can make objects appear closer than they are, it is responsible for allowing water to magnify objects. First, as light is entering a drop of water, it slows down. If the water's surface is not flat, then the light will be bent into a new path. This round shape will bend the light outwards and as it spreads out, the image you see gets larger.
Refraction of Light by 2E1 The Su Zin
After doing research about this topic, I have learnt more concerning with the topic: refraction such as its laws and rules and also about refractive index.
1)Refraction
Refraction refers to the change in direction of light when it moves from one transparent medium into another transparent material which causes it to travel at a different speed.
Light slows down
Visible light is electromagnetic radiation or waveform. The speed or velocity of light in a vacuum is about 186,000 miles per second or 300,000 kilometres per second. The velocity of light or other electromagnetic radiation is typically slower when it passes through a transparent material. For example, the speed of light in water is about 140,000 mi/sec or 226,000 km/sec.
2)Refraction Rules When visible light passes through a transparent material such as glass and water, its velocity(speed) changes according to the index of refraction of the material. The index of refraction of air is about 1.00 and that of water is 1.33. When the beam of light enters water at an angle, it is bent or refracted as a result of the decrease in velocity.
Light is refracted inward when entering medium of higher index of refraction
Light is refracted outward when entering medium of lower index of refraction
The bending occurs because light travels more slowly in a denser medium.
Why does the light beam bend?
Considering a group of soldiers marching into a muddy field at an angle to their direction of travel can explain how a beam of light will be refracted. As the soldiers try to stay in a line, the direction of travel would bend because marching in mud would slow them down, starting with the first group to enter the field. Then, as they leave the muddy area, they go to their original speed, thus bending the direction of travel again. The original direction and the final direction are parallel but displaced.
The same thing happens when a beam of light enters a transparent material at an angle.
Example of how light is refracted when passes through different medium.
3 )INDEX OF REFRACTION
Refractive index is a number which indicates the power of refraction of a given medium relative to a previous medium. The absolute refractive index of a medium is the speed of light in a vacuum (air) divided by the speed of light in that medium.
Symbol is “n”. The larger the index ,the smaller the speed of light.
n = c/v
4)THE EFFECTS OF REFRACTION
Refraction has some unusual effects in everyday life.
-When a submerged object is viewed from above the surface of water, it appears closer to the surface than it is. This is due to light rays from the object being bent away from the normal as they pass out of the water (the more dense medium) into air (the less dense medium).
-The ratio of the real depth of the object to its apparent depth equals the refractive index of water.
Here are some examples of the EFFECTS:
eg1 - Apparent Depth in Water
In the above diagram, the chest seems to be nearer to the surface, but it is not. Refraction causes the chest to appear nearer to the surface than it actually is when it is in transparent material, water .
When you look at something under the water, not only the position of the object is not located at the place you though it was. The shape of the object is also changed. Location of the image and its shape are all depend on the location you view it.
eg2- In this diagram, the straw seems bent in the glass.
Refraction causes point X to appear nearer to the surface at Y so we see that that the straw appears to bend nearer to the surface of the water. This is one of the effect of refraction.
Eg.3 Pencil in water glass
You can also see this effect by putting a pencil in a glass of water. It appears as if the pencil is broken, but it is just because of the refraction of light.
The light from the pencil is refracted as it passes from the water to the glass to air, causing it to be displaced. Since the surface of the glass is curved, the water in the glass also acts as a magnifying glass, slightly enlarging the pencil.
So here is the link for mini short quiz, very simple quiz. =)
http://www.school-for-champions.com/science/light_refraction.htm#Mini-quiz
Acknowledgement
1 . http://sol.sci.uop.edu/~jfalward/refraction/refraction.html
2.http://sg.answers.yahoo.com/question/index;_ylt=ApfjYqHaykzhEnCDtDjBpjYh4wt.;_ylv=3?qid=20070902013243AA3gdvF
3. http://www.school-for-champions.com/science/light_refraction.htm
http://www.phy.ntnu.edu.tw/ntnujava/
4. The Usborne Illustrated Dictionary Of Physics
1)Refraction
Refraction refers to the change in direction of light when it moves from one transparent medium into another transparent material which causes it to travel at a different speed.
Light slows down
Visible light is electromagnetic radiation or waveform. The speed or velocity of light in a vacuum is about 186,000 miles per second or 300,000 kilometres per second. The velocity of light or other electromagnetic radiation is typically slower when it passes through a transparent material. For example, the speed of light in water is about 140,000 mi/sec or 226,000 km/sec.
2)Refraction Rules When visible light passes through a transparent material such as glass and water, its velocity(speed) changes according to the index of refraction of the material. The index of refraction of air is about 1.00 and that of water is 1.33. When the beam of light enters water at an angle, it is bent or refracted as a result of the decrease in velocity.
Light is refracted inward when entering medium of higher index of refraction
Light is refracted outward when entering medium of lower index of refraction
The bending occurs because light travels more slowly in a denser medium.
Why does the light beam bend?
Considering a group of soldiers marching into a muddy field at an angle to their direction of travel can explain how a beam of light will be refracted. As the soldiers try to stay in a line, the direction of travel would bend because marching in mud would slow them down, starting with the first group to enter the field. Then, as they leave the muddy area, they go to their original speed, thus bending the direction of travel again. The original direction and the final direction are parallel but displaced.
The same thing happens when a beam of light enters a transparent material at an angle.
Example of how light is refracted when passes through different medium.
3 )INDEX OF REFRACTION
Refractive index is a number which indicates the power of refraction of a given medium relative to a previous medium. The absolute refractive index of a medium is the speed of light in a vacuum (air) divided by the speed of light in that medium.
Symbol is “n”. The larger the index ,the smaller the speed of light.
n = c/v
4)THE EFFECTS OF REFRACTION
Refraction has some unusual effects in everyday life.
-When a submerged object is viewed from above the surface of water, it appears closer to the surface than it is. This is due to light rays from the object being bent away from the normal as they pass out of the water (the more dense medium) into air (the less dense medium).
-The ratio of the real depth of the object to its apparent depth equals the refractive index of water.
Here are some examples of the EFFECTS:
eg1 - Apparent Depth in Water
In the above diagram, the chest seems to be nearer to the surface, but it is not. Refraction causes the chest to appear nearer to the surface than it actually is when it is in transparent material, water .
When you look at something under the water, not only the position of the object is not located at the place you though it was. The shape of the object is also changed. Location of the image and its shape are all depend on the location you view it.
eg2- In this diagram, the straw seems bent in the glass.
Refraction causes point X to appear nearer to the surface at Y so we see that that the straw appears to bend nearer to the surface of the water. This is one of the effect of refraction.
Eg.3 Pencil in water glass
You can also see this effect by putting a pencil in a glass of water. It appears as if the pencil is broken, but it is just because of the refraction of light.
The light from the pencil is refracted as it passes from the water to the glass to air, causing it to be displaced. Since the surface of the glass is curved, the water in the glass also acts as a magnifying glass, slightly enlarging the pencil.
So here is the link for mini short quiz, very simple quiz. =)
http://www.school-for-champions.com/science/light_refraction.htm#Mini-quiz
Acknowledgement
1 . http://sol.sci.uop.edu/~jfalward/refraction/refraction.html
2.http://sg.answers.yahoo.com/question/index;_ylt=ApfjYqHaykzhEnCDtDjBpjYh4wt.;_ylv=3?qid=20070902013243AA3gdvF
3. http://www.school-for-champions.com/science/light_refraction.htm
http://www.phy.ntnu.edu.tw/ntnujava/
4. The Usborne Illustrated Dictionary Of Physics
Colours of Light by 2E1 Jason
Colour:
Colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue, black, etc. Colour derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors.
White light is a mixture of different colours and when it passes through a glass prism, the light splits up into the colours you see in a rainbow. Spectrum, (white light) consists of Red, Orange, Yellow, Green, Blue, Indigo and Violet. The separation of splitting of white light into its separate colours is known as ‘Dispersion’. The colours of the spectrum can be recombined by using a second prism or spinning a colour wheel, we can get white light.
Mixing Coloured Lights
The primary colours of light are red, blue, and green. You can get white light or any other colour by mixing just three colours. If you mix two primary colours at a time, you will get magenta, yellow, and cyan.
Colour Filters
Colour filter is the clear plastic or glass which only lets through some of the colours meanwhile the other colours is being absorbed.
When white light (spectrum) shines on a coloured object, some of the colours in the spectrum are reflected and some are being absorbed. We can see the colour that is reflected light.
Credits:
http://en.wikipedia.org/wiki/Colour
http://wolfstone.halloweenhost.com/Lighting/colmix_ColorMixing.html
Explore Your World with SCIENCE DISCOVERY 2 [Chapter 8.4, colour]
Colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue, black, etc. Colour derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors.
White light is a mixture of different colours and when it passes through a glass prism, the light splits up into the colours you see in a rainbow. Spectrum, (white light) consists of Red, Orange, Yellow, Green, Blue, Indigo and Violet. The separation of splitting of white light into its separate colours is known as ‘Dispersion’. The colours of the spectrum can be recombined by using a second prism or spinning a colour wheel, we can get white light.
Mixing Coloured Lights
The primary colours of light are red, blue, and green. You can get white light or any other colour by mixing just three colours. If you mix two primary colours at a time, you will get magenta, yellow, and cyan.
Colour Filters
Colour filter is the clear plastic or glass which only lets through some of the colours meanwhile the other colours is being absorbed.
When white light (spectrum) shines on a coloured object, some of the colours in the spectrum are reflected and some are being absorbed. We can see the colour that is reflected light.
Credits:
http://en.wikipedia.org/wiki/Colour
http://wolfstone.halloweenhost.com/Lighting/colmix_ColorMixing.html
Explore Your World with SCIENCE DISCOVERY 2 [Chapter 8.4, colour]
Colours of Light by 2E4 Jeremy Lim
In this topic I have learn about how colours are produce , what is dispersion of light and to recombine colours back after spitting them and also what is the effect of mixing colours as well as what is primary colours.
White light which is also known as ordinary light actually is a mixture of different colours. And when that white light pass through a glass prism the light actually spits up into 7 different colours and that process is call dispersion.
The spectrum consist of 7 beautiful colours, they are red, orange, yellow, green, blue, indigo, violet. It is also difficult to say when one colours ends or start as these colours merge into one another gradually.
The reason why there is always (maybe) a rainbow after a shower of rain is because the raindrops act like small prism and when sunlight passes through them …. They form the colours of the spectrum.
And since we are able to separate those seven colours from the spectrum, thus we are also able to rejoin the seven colours back into white light. And in order to do that is 2 ways.
The first way is to add in another prism or to spin a colour wheel and another
name for the colour wheel is call a Newton disc.
Lights of different colours can be mixed together to produce other colours and in fact white light and light of other colours can be obtained by mixing 3 colours, these colours are red, blue , green. These colours are called primary colours.
Here are the *formula* of colours, red + blue = magenta, red+ green = yellow, blue + green = cyan. And by adding the 3 primary we get white colours.
Clear plastic or glass only let through some colours and the other colours are absorbed are call colour filter. When white light shines on a coloured object, some colour are reflected and some are absorbed.
To end my project work, I want to say that the colour of an object is the colour of the light that is reflected from it into our eyes. And if no light is reflected the object would be black. Black is not a colour it is just something that indicates the absence of light.
Text book resource*
White light which is also known as ordinary light actually is a mixture of different colours. And when that white light pass through a glass prism the light actually spits up into 7 different colours and that process is call dispersion.
The spectrum consist of 7 beautiful colours, they are red, orange, yellow, green, blue, indigo, violet. It is also difficult to say when one colours ends or start as these colours merge into one another gradually.
The reason why there is always (maybe) a rainbow after a shower of rain is because the raindrops act like small prism and when sunlight passes through them …. They form the colours of the spectrum.
And since we are able to separate those seven colours from the spectrum, thus we are also able to rejoin the seven colours back into white light. And in order to do that is 2 ways.
The first way is to add in another prism or to spin a colour wheel and another
name for the colour wheel is call a Newton disc.
Lights of different colours can be mixed together to produce other colours and in fact white light and light of other colours can be obtained by mixing 3 colours, these colours are red, blue , green. These colours are called primary colours.
Here are the *formula* of colours, red + blue = magenta, red+ green = yellow, blue + green = cyan. And by adding the 3 primary we get white colours.
Clear plastic or glass only let through some colours and the other colours are absorbed are call colour filter. When white light shines on a coloured object, some colour are reflected and some are absorbed.
To end my project work, I want to say that the colour of an object is the colour of the light that is reflected from it into our eyes. And if no light is reflected the object would be black. Black is not a colour it is just something that indicates the absence of light.
Text book resource*
Refraction of Light by 2E1 Shahir
For thousands of years, people have noticed that a straight stick placed obliquely in water appears to be broken at an angle where it enters the water. This is the origin of the term "refraction," which means literally "broken back."
Refraction is the change of light that changes direction when it passes from one medium to another.
refraction occurs when light waves travel from a medium with a given refractive index to a medium with another.
At the boundary between the media, the wave's phase velocity is altered, it changes direction, and its wavelength increases or decreases but its frequency remains constant.
For example, a light ray will refract as it enters and leaves glass.the understanding of this concept led to the invention of lenses and the refracting telescope
from a less dense material to a denser material, light will slows down and refracted towards the normal, while from denser material into a less dense material, light speeds up and is refracted away from the normal.
The refractive index of a transparent optical medium, also called the index of refraction, is the factor by which the phase velocity is decreased relative to the velocity of light in vacuum, assuming linear propagation
effects of refraction are : -it causes an object to be nearer than it actually is when a transparent material is on top - a stick will appear to be bent inside a bearker filled with water.
From this topic, i have learned that refraction happens in our everyday life. It causes effects that are very unusual and refraction is an interesting topic to learn.
key points : -refraction happens when light changes direction when it passes from one medium to another -it causes effects that are unusual.
Refraction is the change of light that changes direction when it passes from one medium to another.
refraction occurs when light waves travel from a medium with a given refractive index to a medium with another.
At the boundary between the media, the wave's phase velocity is altered, it changes direction, and its wavelength increases or decreases but its frequency remains constant.
For example, a light ray will refract as it enters and leaves glass.the understanding of this concept led to the invention of lenses and the refracting telescope
from a less dense material to a denser material, light will slows down and refracted towards the normal, while from denser material into a less dense material, light speeds up and is refracted away from the normal.
The refractive index of a transparent optical medium, also called the index of refraction, is the factor by which the phase velocity is decreased relative to the velocity of light in vacuum, assuming linear propagation
effects of refraction are : -it causes an object to be nearer than it actually is when a transparent material is on top - a stick will appear to be bent inside a bearker filled with water.
From this topic, i have learned that refraction happens in our everyday life. It causes effects that are very unusual and refraction is an interesting topic to learn.
key points : -refraction happens when light changes direction when it passes from one medium to another -it causes effects that are unusual.
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