Nitrogen is the most abundant gas in our atmosphere and is luckily quite inert. It generally just sits there doing nothing while the more chemically relevant gasses like oxygen and carbon dioxide interact with our bodies. Almost all plants, however, require some nitrate (NO3–) in order to grow. There is a natural cycle of nitrogen where animals who die release the nitrogen from what they’ve eaten back into the soil and also an atmospheric cycle where occurrences like lightening can convert nitrogen in the atmosphere into nitrogen dioxide (NO2) which is then dissolved by the rain and ends up in the soil as a nitrate. These natural methods can sometimes be too slow for industrialised agriculture and so ammonia (NH3) can be added which is changed into nitrates by bacteria in the soil.
One of the more abstract aspects of global warming, from my perspective, is the tangible short term results. It is predicted that an increase in the sea’s surface temperature will result in an increase of tropical cyclone intensities. The sea is the primary of source of energy which feeds the storm and the oceans where cyclones are known to develop (North Pacific and North Atlantic) have increased by half a degree over the last 50 years. Predictions of increased destruction stray wildly and many previous studies have left out key sections on the increased size of cyclones with increased temperature. Another fault is that previously gathered data doesn’t always record storm sizes resulting in studies based on the assumption of a maximum possible storm size. If the increase of sea’s temperature does increase the size of storms as is firmly believed, these past predictions require updating.
Desertification is the process where a piece of dry but fertile land progresses to become literally a desert. It is almost exclusively caused by the loss of plant life around the desert border. Without plants to bind the soil it is quickly washed away by rain or more likely blown away in the wind. The nutrients contained in the plants are also lost resulting in nothing but arid sand remaining. Normally these plants are either devoured by grazing animals, chopped away for fire wood or perhaps just simply die off in a drought. The encroaching desert normally has adverse effects towards small groups of natives but there are some areas where the results could be more severe. The Ordos desert in Inner Mongolia (which is actually in China) has severe desertification taking place. Considering that northern China is considered the farming and livestock zone, the progression of previously static sand dunes into the roaming variety has been quite unnerving.
When you think of magnetic metals, the three ferromagnetic elements come to mind: cobalt, nickel and iron. It is also not surprising that some of the alloys containing these metals are also ferromagnetic such as steel as well as some of the crystalline compounds like iron oxide (Fe2O3). Now although these are stated as the only ferromagnetic elements there is a caveat. Perhaps it would be more accurate to say that they are the only ferromagnetic elements at room temperature. Materials have what is called a Curie temperature. This is a critical point at which the permanent magnetic dipoles get scattered by the heat resulting the loss of permanent magnetism and the onset of induced magnetism. The elements of dysprosium (Dy), terbium (Tb) and gadolinium (Gd) are also ferromagnetic with terbium and gadolinium needing to be cooled to 219 K and 292 K respectively and dysprosium requiring an extremely low 88 K.
The importance of the Sun in our solar system cannot be overstated. When considered, it is quickly realised that almost all sources of energy on this planet come from the Sun. For solar power it is obvious, but wind power is caused by the temperature gradient the Sun produces and fossil fuels originally started out as plants absorbing energy through photosynthesis. The two main exceptions are tidal power, which is a conversion of the Earth and Moon’s rotational kinetic energy and geothermal power, which is gained from nuclear decay in the Earth’s core.
I once heard the fact (I believe from Professor Richard Dawkins) that echolocation has involved independently on four different occasions: bats, dolphins and two species of cave dwelling birds. How true this is technically, I’m not certain on, considering there are shrews in Madagascar with much lower amplitude, frequency modulated version of echolocation. There is also evidence that echolocation evolved independently in two separate lineages of bats (and I really an lost about how whales fall into this). Although these acoustic techniques can be used by animals to locate their prey quite easily, it also makes it a lot easier for us to find them, especially in the case of dolphins.
Svante Arrhenius was a Swedish physicist and chemist whose name should be recognisable to anyone who has studied physical chemistry due to his ever relevant Arrhenius equation which describes how a value called the rate constant changes with activation energy and temperature. Apart from physical chemistry he worked on geology and the origin of the ice ages. As part of this study, in 1896, he wrote a paper in which he calculated that the effect of halving the carbon dioxide in the atmosphere would decrease the temperature of Europe by about 4 °C. This was the first prediction linking carbon dioxide to temperature changes ever made and still provides solid evidence for the premise.