Water questions

The speed at which light propagates through transparent materials, such as glass or air, is less than c. However, this "slowing of the light" is only due to the fact of photos being absorbed and re-emitted after a slight delay between atoms. When a photon is emitted, it's speed is always c. In exotic materials like Bose–Einstein condensates near absolute zero, the effective speed of light may be only a few metres per second.

The dihydrogen monoxide parody involves calling water by the unfamiliar chemical name "dihydrogen monoxide" (DHMO), or "hydroxylic acid" in some cases, and listing some of water's well-known effects in a particularly alarming manner, such as accelerating corrosion and causing suffocation. The parody often calls for dihydrogen monoxide to be banned, regulated, or labeled as dangerous. It illustrates how a lack of scientific literacy and an exaggerated analysis can lead to misplaced fears.

Blue ice occurs under the surface of a glacier as a result of repeated, slow thawing and freezing of water. This process speeds up when snow falls on the top of a glacier, the ice compresses, air bubbles are squeezed out and ice crystals enlarge, making the ice appear blue. In the Greenland environment this process takes from 100 up to 150 years.

Hydrogen peroxide is a chemical compound with the formula H₂O₂. In its pure form, it is a pale blue, clear liquid, slightly more viscous than water. It is used as an oxidizer, bleaching agent and antiseptic.

World Water Day is an annual UN observance day (always on 22 March) that highlights the importance of freshwater. The day is used to advocate for the sustainable management of freshwater resources. World Water Day is celebrated around the world with a variety of events. These can be educational, theatrical, musical or lobbying in nature.

The Armstrong limit or Armstrong's line is a measure of altitude above which atmospheric pressure is sufficiently low that water boils at the normal temperature of the human body. Humans absolutely cannot survive above this limit in an unpressurized environment. Above Earth, this begins at 18–19 km (11–12 mi; 59,000–62,000 ft) above sea level. The term is named after United States Air Force General Harry George Armstrong, who was the first to recognize this phenomenon

4 degrees C turns out to be the temperature at which liquid water has the highest density. If you heat it or cool it, it will expand. The expansion of water when you cool it to lower temperatures is unusual, since most liquids contract when they're cooled.

Ebro is the longest river in Spain, Pechora flows through the European part of Russia, and Sawa is the largest right tributary of the Danube. Oranje is a river in Africa, has its source in the Dragon Mountains, flows through Lesotho, South Africa and Namibia and flows into the Atlantic.

The amount of water in the human body ranges from 50-75%. The average adult human body is 50-65% water, averaging around 57-60%. The percentage of water in infants is much higher, typically around 75-78% water, dropping to 65% by one year of age.

The water molecule maintains a bent shape (at around 104.5 degrees) because of two considerations. First, the tetrahedral arrangement around the oxygen; and second, the presence of lone pair electrons on the oxygen.