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May 4, 2009 | 01:17 PM
#16
Xenophoridae, common name carrier shells, are a taxonomic family of medium-sized to large sea snails, marine gastropod mollusks in the clade Littorinimorpha.
Xenophorids are unusual in that in many of the species the animal cements small stones or shells to the edge of the shell as it grows, thus the shells of those species are sometimes humorously referred to as "shell-collecting shells". The genus name Xenophora comes from two ancient Greek words and means "bearing (or carrying) foreigners".
Xenophorids are unusual in that in many of the species the animal cements small stones or shells to the edge of the shell as it grows, thus the shells of those species are sometimes humorously referred to as "shell-collecting shells". The genus name Xenophora comes from two ancient Greek words and means "bearing (or carrying) foreigners".
May 4, 2009 | 01:29 PM
#17
Xenophoridae, common name carrier shells, are a taxonomic family of medium-sized to large sea snails, marine gastropod mollusks in the clade Littorinimorpha.
Xenophorids are unusual in that in many of the species the animal cements small stones or shells to the edge of the shell as it grows, thus the shells of those species are sometimes humorously referred to as "shell-collecting shells". The genus name Xenophora comes from two ancient Greek words and means "bearing (or carrying) foreigners".
Xenophorids are unusual in that in many of the species the animal cements small stones or shells to the edge of the shell as it grows, thus the shells of those species are sometimes humorously referred to as "shell-collecting shells". The genus name Xenophora comes from two ancient Greek words and means "bearing (or carrying) foreigners".
May 16, 2009 | 05:14 PM
#19
Why is the sky blue?
Why is the sky blue?.....
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.
(pic for mcfarlnd)
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.
(pic for mcfarlnd)
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
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