My Science School

Snow lines are clearly visible on mountains. They mark out the area above which a mountain is permanently covered in snow.

The highest points of a mountain are much colder than the lower points. The snow which falls on the higher regions never thaws because it is so cold. In the summer, however, the warmer weather begins to melt some of the snow. This causes the snow line to move up the mountain.

As the summer months pass by and the winter months return, the snow line moves further down the mountain once again.

In colder regions, the snow line is close to ground level, but where the air is warmer, the snow line is closer to the Equator.

Fact File: Mountains such as the Rockies in South America, do not see a dramatic movement in the snow line. This is because they are so high up. The climate is very cold in winter and the summers are short-lived.

 

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Water turns into snow at temperature above -40 . Snow forms when water in clouds freezes into tiny ice crystals. This moist air freezes around minute dust particles or chemical substances floating in the clouds. These particles become the core, or the nucleus, of each crystal. Snow crystals grow in size when more water crystallizes around a particular nucleus. This happens more if the air is humid.

Snowflakes are formed when a number of crystals join together in clusters. The structure of snowflakes is often a beautiful, hexagonal form. It is believed that no two snowflakes can be identical. These fall from the clouds onto land as snow.

Fact File: Eskimos live in houses made completely of snow called igloos. The Eskimos cut away blocks of snow and build the igloo as though they are bricks. Because where they are built is so cold, the igloos do not melt.

 

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When vegetation first starts growing in newly formed soil, it is disadvantage because the soil will not be nutrient-rich. As the plants die, they enrich the soil, allowing more plants to take advantage of this. As the soil gets older, it has gleaned more and more nutrients from dead plants – and more and more plants are able to grow successfully in the soil. Climax vegetation occurs when the vegetation is totally suited to soil. In reality, this can never last permanently due to the ever-changing environment.

Fact File: Rainforests have developed in areas where the soil is very fertile and where there is a great deal of rainfall. The varied vegetation suggests the soil is extremely nutrient-rich.

 

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Soil changes its appearance when the biological or chemical make-up of it varies. For example, red soil is found in areas where there is a high content of iron compounds. Oxisol is a good example of this; it is found in tropical regions where both chemical and biological activities are high.

If you thought that all soils are brown, think again. Soil colours range from black to red to white. Sometimes it can even be blue! Soil colour mostly comes from organic matter and iron. Topsoil is often dark because of organic matter. An even, single colour indicates the soil is well drained. In contrast, rusty spots and grey patches (sometimes even a light blue in colour) indicate poor drainage.

Fact File: Soil is not just a single, consistent layer of material.

 

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There are two main ways in which rivers begin. Some rivers start when a natural spring releases water from underground. These are often small trickles of water which develop into small streams. In turn these streams increase in size until they are acknowledged as rivers.

Other rivers begin when persistent rain makes a groove or a channel in a piece of land. As more and more rain falls into this channel, a flow of water slowly begins. Just like the springs, a stream can soon develop into a river.

Fact File: When rivers reach land close to sea level, they begin to meander, forming a snake-like shape on the land. This is caused by the gradual dropping of the sediment it carries where the flow is weak.

 

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Water cycles demonstrate how water evaporates from the oceans then rises in the air to form clouds. In areas of low pressure, the clouds release the water as rain. This falls into the oceans again, or falls onto the land where it gradually works its way back into the oceans via streams and rivers. This is a continual, cyclical process.

However, in some areas of the world where there is no rainfall for long periods of time, local water cycles do stop. When one event in the cycle fails to happen, the cycle breaks down.

But water can neither be created nor destroyed – it will always exist in some form. If you consider the world as a whole, with one big water cycle, the processes involved are always occurring somewhere: this cycle never stops.

Fact File: Too much rainwater can have disastrous effects on the land. Flooding washes away fertile soil, and begins eroding the land.

 

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The longest drought in recorded history took place in Calama, in the Atacama desert of Northern Chile.  For four centuries, beginning in 1571, no rain fell in the area. It was not until 1971 that rainfall was first recorded again. The Atacama desert, which lies between the Andes and the Pacific ocean, is recognized as the driest place in the world.

The Atacama desert remains so dry because it lies in a region where there is constant high air pressure, with little air movement, and with few clouds overhead.

Fact File: Some people believe that animals are good predictors of weather. One such belief is that if cows are standing in their field, then dry weather is expected. If they are lying down, however, rain is expected.

 

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Water becomes salty when minerals (including salts) dissolve into it. This process begins when rainwater falls on the land and erodes rock. The minerals found in rock are dissolved into the rainwater.

These dissolved minerals in the rainwater enter streams and rivers, gradually working their way into the seas and oceans.

This is a process which is constantly taking place, so the level and concentration of salt in the oceans and seas is always increasing. Some of the minerals are consumed by organisms in the water, but the vast majority of them make up the saltiness of the water.

Fact File: Lighthouses were built to worn ships at sea that they were approaching land and rocky water. Their beam of light across the waves made travelling by boat much safer.

 

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The longest heatwave ever recorded was in Marble Bar, Australia when the temperature stayed above 38 . It lasted for 162 days from 23 October 1923 to 7 April 1924.

The highest average annual temperature recorded is 34.4  in Dallol, Ethiopia.

The lowest recorded temperature (outside of the poles) was -68  in Verkhoyansk, Siberia, on 6 February 1933.

The lowest average annual temperature of -56.6  was recorded at the Plateau Station, Antarctica.

Fact File: Some living things have adapted to survive long periods of time without water. Plants such as cacti have the ability to conserve water. They also minimize water loss as they have no leaves, and photosynthesis takes place in the stem. They have roots which reach deep into the ground for water.

 

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        How many kilograms of food do you consume a day? However hard you try, it will not be more than three kilograms. Do you know how much as elephant consumes a day? Compared to other animals, an elephant has a huge body frame. Therefore, elephants have to eat and drink proportionate to the size of its body.

        Do you know that an elephant consumes about 180 kg of food each day? It spends about 18 hours just eating. Elephants are herbivores and feed on grasses, tree foliage, and bark, twigs and other vegetation. African elephants largely prefer tree leaves, bark, and branches, Asian elephants, on the other hand, shrubs, in addition to juicy leaves and fruit.

        These animals need to drink a lot of water too. An elephant consumes about 190 litres of water a day. That is how much water a standard bathtub can hold!

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        Have you ever gone close to an elephant? The most intimidating aspect of an elephant is its size. An enormous tusker is an awe-inspiring sight. While the Asian elephant is big, the African bush elephant is bigger.

        The most obvious difference between the African and the Asian elephants is the size of their ears. The African’s ears are twice as big as those of the Asian. There is difference in the structure of the chewing surface of the teeth too. While the teeth of the Asian elephant have close narrow loops, the African elephants have wider, diamond shaped surfaces.

        There are four toes on an Asian elephant’s hind foot, while the African has only three. There are more folds or rings in the African elephant’s trunk. Its trunk has two fingers at its tip. The Asian counterpart has only one finger at the end of the trunk. Another significant difference between these animals is that while among the Asian elephants the females do not tusks, the female African elephant has long tusks!

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        Although elephants are the biggest land animals, there is variation among the species in terms of their size and weight.

        The African bush elephants are largest in the Elephantidea family. The males of these species are about 3.2 metres tall at their shoulder. They weigh up to 6 tonnes. Male Asian elephants, on the other hand, grow up to 2.75metres at their shoulder. They are much lighter than African bush elephants, with a weight about 5 tonnes. The smallest elephant species is the African forest elephants. They grow to a height of about 2.2 metres and weights between 2-5 tonnes.

        There are differences in physical features between the male and the female elephants. Male African elephants are typically 23% taller than females, whereas male Asian elephants are only around 15% taller than females. There are about 326 to 351 bones in an elephant’s body.

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        There will be hardly anyone who does not know the answer to this question. The largest living land animal is none other than the elephant. Usually two kinds of elephants are identified in terms of their location: the Asian, and the African variety. Of the African bush elephants, with their huge ears and longer tusks, are bigger than their Asian counterparts. These animals are known for their physical features and great strength. They live long, and possess complex herd behavior.

        These animals belong to the family Elephantidae. There are three species identified among elephants: the African bush elephant and the Asian elephant. They play a major role in nature and therefore are considered keystone species due to their impact on nature.

        In Asia, these animals are domesticated for various hard tasks. In times gone by, they played a key role in wars. Today, these majestic animals are exploited by Man for entertainment, and are put on display in zoos.

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        It has been a perennial quest of Man to know where he came from. While the theory of evolution gave him clues as to who his closest relatives are. Great apes are much like us, sharing great genetic resemblance. In fact, bonobos share 98.5% of the human DNA. This is the reason why they possess very human-like qualities too.

        Bonobos are profoundly intelligent and possess deep emotional capacity. It is reported that bonobos have picked up many important features of human culture while in captivity. Most of this was accomplished through their ability to observe, and assimilate ideas.

        They are intelligent enough to learn how to   communicate, use tools and play music. In a case reported, a female bonobo tried her hand at driving a golf cart, though a short while later, it crashes on to a free!

        No doubt, a bonobo is very much like a human.

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          As its name suggests, the pygmy chimpanzees is not as big as the common chimpanzee. As is the common feature among all primates, the adult female bonobo is somewhat smaller than the adult male. While the male is about 35 to 60 kilograms, the female is only 30 kilograms. The length of a bonobo from nose to rump when it is on all fours is 70 to 85 cm. However, when standing upright, these animals can reach a height of about 115 cm. The head of a bonobo is relatively smaller than that of the common chimpanzee. This is mainly due to the less prominent ridges it has over its eyes.

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