Monday, December 11, 2006

A Day at the Park

A couple of months ago I went to the playground with my nephew. I keep in mind the day like be yesterday. The climate was cool and clouds were transparency. I sat by myself and watching the play and watch everything take place something like exciting things just watching people, but surprised at what I did discover. Children were all over the place and were tiresome coats that had their preferred characters on them. A girl had plum mittens with a teletubby on them.

Before I know it, it was time to depart as my nephew and I walked back to my car the thought of being a kid again would be vast. One of the boys complicated in the game fell down and began to shed tears. There were only two mothers at the playground and seven children not including a baby by the side of one of the mothers. They would lash out, wet sand all over their backs as they ran. Although that was going on, the other children discovered that when they went down the slide it shocked them.

Tuesday, December 05, 2006

colour in eye

The ability of the human eye to distinguish colors is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. The retina contains three types of color receptor cells, or cones. One type, relatively distinct from the other two, is most responsive to light that we perceive as violet, with wavelengths around 420 nm. (Cones of this type are sometimes called short-wavelength cones, S cones, or, misleadingly, blue cones.) The other two types are closely related genetically and chemically. One of them (sometimes called long-wavelength cones, L cones, or, misleadingly, red cones) is most sensitive to light we perceive as yellowish-green, with wavelengths around 564 nm; the other type (sometimes called middle-wavelength cones, M cones, or misleadingly, green cones) is most sensitive to light perceived as green, with wavelengths around 534 nm.

Light, no matter how complex its composition of wavelengths is reduced to three color components by the eye. For each location in the visual field, the three types of cones yield three signals based on the extent to which each is stimulated. These values are sometimes called tristimulus values.