Why do we see a red colour when we hold our palm against a light source?
Why are fishes not able to survive in distilled water?
What causes blue fingernails?
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SCIENCE FACTS
SCIENCE FACTS
Why do we see a red colour when we hold our palm against a light source?
In the visible spectrum, red has the highest wavelength, and lies in the range of 650- 750 nm. Its depth of penetration into human tissues is approximately around 3mm as seen from the graph below. This is much higher than the other wavelengths present in the visible spectrum. Since light at the edges of our fingers have to traverse a smaller distance, around 2mm to 5mm, we see red to be the prominent colour. This is referred to as Near- Infrared window( NIW) which defines the range of wavelengths where light has its maximum depth of penetration. This property has been utilized in numerous applications ranging from spectroscopic imaging to treatment of brain tumours.
Why are fishes not able to survive in distilled water?
Take a fresh grape fruit and keep it in distilled water for an hour. It is stouter than before. Another fresh grape fruit kept in salty water for an hour will appear slim and wrinkled. The grape has dissolved minerals, sugars and other ingredients in its juice. The skin of the grape is a semi permeable membrane across which water can diffuse from one side to the other through osmosis. When the grape is kept inside distilled water, the concentration( salinity) of juice in the grape is higher than that of water and water moves osmotically from outside the grape to inside. Hence the grape appeared stouter. The reverse happened in the case of salty water.
The skin of the fish is like the skin of the grape fruit. If the fish is in distilled water, there is an osmotic flow of water from outside the fish to the inside because the salinity of the fish body is higher than that of water. Thus there is a danger of dilution of the body fluids of the fish or at worst that of being blown out if the fish is to be in distilled water for a very long period of time.
What causes blue fingernails?
Blue fingernails are caused by a lack or low level of circulating oxygen in your red blood cells. This condition is known as cyanosis. It occurs when there isn’ t enough oxygen in your blood and the skin or membrane below the skin
WINSPIRE: Empowering youth | February, 2017