Shreyash

Journal Entry Week 3

1. Analyse why red sunsets can sometimes be more impressive when there is more dust or pollution in the air than usual.

Red sunsets can be sometime more impressive when there is more dust or pollution because the light has more material in the air which it has to reflect off but where as if there was no pollution their would be less light being reflected therefore a less impressive sunset.

1. Describe what happens inside water droplets to cause a rainbow and explain how you can tell whether a rainbow is a primary or secondary.

When it is raining and light hits a water droplet, the water droplet acts like a prism when the light enters the droplet the light is split into the colours of the rainbow then those colours are reflected out into the a rainbow in which we see. In a rainbow there is only one internal reflection. A secondary rainbow is when the light enters the water droplet, splits the light but rather than having one internal reflection their will be two and because of this colours are filled so that red will be at the bottom rather than the red being at the top. That is how we can tell is the rainbow is secondary or not.

nvestigate the two types of sight defect- long-sightedness and short sightedness.

Find the following information:

1. what causes the defect

 Long-sightedness: long-sightedness is caused by the light rather than being focused on the retina it is focused behind the retina which causes a blurry image.

Short-sightedness: Short-sightedness is caused when light is focused in front of the retina rather than being focused on the retina this will cause blurring of an image like long-sightedness.

1. the symptoms displayed

Short-sightedness: Causes distant objects to appear blurry and unfocused, while nearby objects remain in focus. (http://hcd2.bupa.co.uk/fact_sheets/html/myopia.html#1)

 Close objects appear fuzzy or blurry, while distant objects remain in focus.

 Headaches or tired eyes. In young people with long sight, the eyes can still focus on near objects, for example when reading a book. But the muscles in the eye have to contract more to allow this. So you might find that you get headaches when you read, write or do other near work, and that your eyes feel tired.  

(http://hcd2.bupa.co.uk/fact_sheets/html/long_sightedness.html)