Why is red the top colour while violet at the bottom?

The amount by which light is refracted depends upon its wavelength, and hence its colour. Blue light (shorter wavelength) is refracted at a greater angle than red light. Red has a longer wavelength followed by the other decreasing colours in the rainbow.

Dispersion of white light.

When a white light is incident on the first surface of the prism it gets refracted. But each constituent of the white light gets refracted through a different angle, i.e., white light gets dispersed. When these colours are incident on the second surface of the prism they again undergo refraction (they get refracted from a denser to rarer medium) and the colours are separated further. Thus a beam of white light incident on a prism splits into its constituent colours to form a spectrum. Each constituent of the white light is deviated towards the base of the prism. Violet colour suffers the maximum deviation and red the least. The spectrum obtained is impure as the colours in the spectrum do not have any sharp boundaries i.e., each colour merges gradually into the next.
taken from: http://www.tutorvista.com/content/science/science-ii/human-eye-colourful-world/dispersion-white-light-prism.php

this video gives a simple explaination about light dispersion.

Refraction

Refraction is the change in direction of a wave due to a change in its speed. This is most commonly observed when a wave passes from one medium to another at an angle.

If a light wave passes from a less dense medium in which it travels slow into a medium in which it travels fast, then the light wave will refract away from the normal. In such a case, the refracted ray will be farther from the normal line than the incident ray. On the other hand, if a light wave passes from a denser medium in which it travels fast into a medium in which it travels slow, then the light wave will refract towards the normal. In such a case, the refracted ray will be closer to the normal line than the incident ray is.

reference: http://en.wikipedia.org/wiki/Refraction

Reflection- Convex, concave and plane mirrors.

Plane mirrors.

Plane mirrors, the image is said to be a virtual image. Virtual images are images which are formed in locations where light does not actually reach.

There are some characteristics of a plane mirror:

1. Images are virtual.
2. If you view an image of yourself in a plane mirror, you will quickly notice that there is an apparent left-right reversal of the image.
3. The object distance is equal to the image distance. That is the image is the same distance behind the mirror as the object is in front of the mirror.
4. Dimensions of the image are the same as the dimensions of the object.

Convex mirrors.

A convex mirror is described as a portion of a sphere which had been sliced away, that bends out. If the outside of the sphere is silvered such that it can reflect light, then the mirror is said to be convex.

Concave mirrors.

A concave mirror is a also described as a portion of a sphere which had been sliced away, that bends in. If the inside of the sphere is silvered such that it can reflect light, then the mirror is said to be concave.

reference: http://www.physicsclassroom.com/class/refln/

Reflection

Reflection is throwinf back or deflection of waves, such as light or sound waves, when they hit a surface. Reflection occurs whenever light falls on an object. The law of reflection states that the angle of incidence (the angle between the ray and a perpendicular line drawn to the surface) is equal to the angle of reflection (the angle between the reflected ray and a perpendicular to the surface).

reference: http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0006047.html

Snell's Law

Snell's law, is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water and glass.

Snell's law is used to determine the direction of light rays through refractive media with varying indices of refraction. The indices of refraction of the media, labeled n1,n2 and so on, are used to represent the factor by which a light ray's speed decreases when traveling through a refractive medium, such as glass or water, as opposed to its velocity in a vacuum.
As light passes the border between media, depending upon the relative refractive indices of the two media, the light will either be refracted to a lesser angle, or a greater one. These angles are measured with respect to the normal line, represented perpendicular to the boundary. In the case of light traveling from air into water, light would be refracted towards the normal line, because the light is slowed down in water; light traveling from water to air would refract away from the normal line.
Refraction between two surfaces is also referred to as reversible because if all conditions were identical, the angles would be the same for light propagating in the opposite direction.

Taken from: http://en.wikipedia.org/wiki/Snell's_law

Are sports drink acidic?

Are "sports drinks" acidic?

There are all together 3 different types of sports drinks: Isotonic, Hypertonic, Hypotonic.

Sports drinks contain acid which may be harmful to us, especially for our teeth. All acids have an erosive potential but the method of drinking will influence whether or not those acids affect the teeth. Method of drinking? Sports drinks should be drank quickly and is advised to use a straw and not be held or swished around the mouth. Spending too much time drinking it or leaving it in your mouth for a long time, may cause erosion. Putting the drink into the refrigerater helps reduce the erosive potential as the acid dissolution constant is temperature dependant.

Taken from: http://www.brianmac.co.uk/drinks.htm

A new beginning.

hello! haha, i had to create a new blog since i forgot my pass.

haha k, anw...

Q1. Why cant we wear gloves to press the lift buttons?
i cant find any answers online... but i think it has something to do with heat.

what i think is, like especially for those sensitive to touch lift button, in order for it to work, they will have to detect the heat from our fingers.. And when we're wearing gloves to press the lift buttons, heat cannot pass through the gloves, hence, they cannot detect the heat and it wont work.

please do correct me if im wrong.

Q2.Why do ice stick to your fingers?

Our skin has high moisture content and very appropriate to form the bond with the oxygen atoms and hydrogen atoms that are inside the ice facing outwards which causes them not to connect with the other molecules to form hydrogen bond. So when our finger meets with ice, they stick together.

Reference: http://www.madsci.org/posts/archives/2003-04/1050004418.Es.r.html