TaNuj^’s Weblog

Red sunsets

Sunlight (what we call “white light”) is made up of all different colors of light, each having a different wavelength. During a sunset, more red light is scattered toward you because of aerosols in the lower atmosphere, compared to the amount of blue or green light. Since, at sunset, sunlight is passing through a much longer path of the lower atmosphere than when the sun is overhead, the effect of the aerosols becomes much stronger. So, you end up seeing more red light that any of the other colors of light, and the sky appears red.

Rainbows

Rainbows are optical illusions that cause a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth’s atmosphere.Rainbows can be caused by other forms of water than rain, including mist, spray, dew, fog, and ice. Moreover, rainbows can have shapes other than a bow (arc), including stripes, circles, or even flames.The light is first refracted as it enters the surface of the raindrop, reflected off the back of the drop, and again refracted as it leaves the drop.

Long-sightedness

Long-sightedness (hyperopia) is a common condition that affects the ability to focus on objects which are at short distances. In a long-sighted eye, the light focuses behind the retina, blurring the image. If it is significant, long-sightedness can cause vision problems, headaches and tiredness. Glasses, contact lenses and laser techniques are used to correct long-sightedness.

Short Sightedness

Myopia is another name short sightedness is the most common refractive error, affecting one in five Australians. Myopic patients are nearsighted; they see close objects more clearly, but distant objects are blurry or even indistinguishable. Myopia occurs when the eye is too long or the cornea is too steep. As a result, light rays entering the eye fall in front of the retina instead of directly on it.

1. Describe TWO things that you have learnt during this lesson.

This lesson I have learnt about refraction and total interrior reflection.

Refraction-Is the bending of light ray as it passes into a different substance. Light changes its speed as it passes from different optical density.

Total internal reflection- The light is unable to escape from the substance its in.

2. Outline THREE things you know about optical technologies. Three things i know about optical technologies are:

- There are many optical instruments in use. A few examples of optical instruments include, a  endosope, telescope, microscope, binaucular, and there are many more.

-  Optical technologies have the function to refract and reflect light.

-  Optical technologies use light.