Insects

       Insects can adapt to any habitat very easily and have conquered most of the part of the earth except the poles and oceans.

       They are small creatures and their body is divided into three parts – head, thorax and abdomen with a pair of antennae, eyes and mouthparts that are locates on its, head. It has two pair of wings attached to the thorax or mid part of its body. Its leg are very flexible. They are the largest varied form of animal life. An insect does not have bones but its outer shell is rather like a suit of armor. Its eyes are unusual as it is made up of tiny lenses.

       Each eye is a collection of many eyes. Like other animals insects also lay eggs. When these insects hatch, larva like animals come out and gradually they form insects. The larva of a butterfly is called a caterpillar. Insects like grasshopper and dragonflies do not produce larva, instead they produce nymph which looks like miniature wingless insects. Insects feed both on plants and animals.

       Social insects – Social insects live together in large groups or colonies. Ants, termites, bees and wasps are some examples of social insects. They build large nests.
They are very active, as some are food collectors, some builders, some protect the colonies while some breed more insects. Insects communicate with each other in different ways. Some pass messages by chirping while some rub their legs on their wings.

Giant stick – The giant stick of Indonesia is the longest insect found in the world. It is very difficult to detect them as they look very similar to twigs on the trees. They do not make any movement during daytime. It is only curing night that they become active.

Termites – Termites usually live in underground colonies. They are even known as white ants and resemble cockroaches. They make amazing mounds. Termite queens live up to 50 years. They can be threat to people’s homes particularly to paper, clothes and furniture. Some of the termites even eat wood, though cellulose in the woods id hard to digest, they are provided with special organisms their stomachs which digests cellulose.

Locust – Locust is one of the larger varieties of grasshopper. Migratory locusts are fearsome pests as they destroy the crops. Some locusts can eat their body weight as everyday meal.

Honey bee – Honey bee live in colonies and perform specific jobs. The honey bee colony consists of one queen and thousands of worker bees. They live in beehives. A queen bee lays more than 1,500 eggs in a day and 250,000 eggs in a season and more than 1,000,000 eggs in its lifetime. Bees generally live for one or two years except the queen who lives for nine years. Bees swallow nectar that they gather from the flowers and special enzymes combine with nectar in honeys bees stomach. The water present in a nectar evaporates. After evaporation the honey can remain in the hive for a long time without getting spoilt. This honey can remain in the hive for future. Bees get attracted to the bright colors and smell of the flower and they generally fly around the area of a hive looking for sources.

Ants – Ants usually nest underground which consists of several rooms, tunnels and chambers. These chambers act as stores and nurseries where eggs are hatched. Ants generally love sweet things. The honey dew produced by aphids is liked by certain ants. The ants protect the aphids from predators such as lady brigs and in return the ants collect the honey dew secreted by aphid bodies.

Galaxy

        Galaxy is a huge group of stars held together by a force of gravity. They are so big that they are also called as the “Island Universe”. They are of different shapes and sizes.

1. How many galaxies are there and name the biggest galaxy near our Milky Way?
        There are about hundred billion galaxies in the universe. The biggest Galaxy near to our Milky Way is the Andromeda Galaxy.

2. What are the three forms of galaxies?
        The three forms of Galaxies are Spiral, Elliptical and Irregular. Spiral galaxies have a central nucleus with great spiral arms trailing around it. Elliptical galaxies show purely elliptical shape without any spiral arms. Irregular galaxies show no definite geometric pattern or shape.

3. Do all galaxies have a definite shape?
        All the Galaxies do not have a definite shape. Galaxies can have the shapes of spirals and ellipses.

4. What kind of materials do galaxies consist of?
        Galaxies consist of three kinds of materials: gas, stars and dark mater.

5. How are the galaxies grouped in space?
        The galaxies are grouped in clusters. According to the scientists’ viewpoint, there gay be about thousands of galaxies in each cluster.

6. What is the peculiar feature of Milky Way?
        The peculiar feature of Milky Way is that it has bright band of light that runs almost in a perfect circle through it.

7. Briefly describe our galactic nucleus.
        Our galactic nucleus is about 32,000 light years away from the Sun. It appears to be a rotating disc of gas. Here new stars are being born continually. The area is already full with grown stars.

Ferns

       Ferns are non dowering plants. These plants have roots and stem which help to absorb water and carry them to the leaves. They do not produce seeds or flowers, instead they use spores to reproduce.

       Their leaves which are known as fronds, contain spores known as sporangia. This sporangia has spores on them. When these spores mature, they open and yet scattered by the wind. There are nearly 6,000 species of ferns found all over the world especially in the equatorial regions.

       During carboniferous period the forests were dominated by great fern tree whose trunks gradually turned into fossil coal. One of the best known ferns are bracken which cover the entire ground with its feathery fronds and the male fern.
                            Ferns

Chinese civilization 3

1. Describe the development of art during the period from 1766 to 1122 B.C.
       By about 2000 BC, people in China had learnt from the people of West Asia how to make bronze out of copper and tin. They began to make many jars and plaques (flat pieces) out of bronze that were used for worshipping their gods. Right from the beginning, these were of high quality.

       About 1300 BC Late Shang rulers brought bronze pitcher from Henan of about 1100 BC, with inscriptions. These bronze jars and boxes were cast in molds using the lost-wax technique. Usually they were cast in several different pieces and then soldered together with melted bronze or tin.

       Some of them were plain with just a few lines cut (incised) into them. Other jars and goblets had lots of fancy decorations sticking out all over them. Some were abstract designs, others showed plants or animals or mythical monsters like dragons. Some showed demons, or human faces.

       Towards the end of the Shang Dynasty, about 1200BC, people began to write messages on these bronze jars and cups using the earliest Chinese pictograms.

2. How far did the art develop further during the Chou dynasty?
       During, the Chou Dynasty, often the shapes of the jars were more complicated than they had been before. As more and more people learnt to write, it became more common to put long inscriptions on the jars. People made special bronze jars for their ancestors, and wrote long inscriptions about their own lives, so that their ancestors and descendants would know what they had done. A lot of the jars were in animal shapes like birds and dragons. Towards the end of the Eastern Chou period, about 300 BC, artists began to create the first Chinese pictures of whole scenes with several people and a landscape, often hunting scenes.

       They also continued to make jade ornaments and decorations in complicated shapes with carving on them. Pottery techniques became more complicated too, with wheel made pots being fired hotter (this makes them harder) and sometimes with a greenish glaze on the surface. It was also in the Eastern Chou period that people in China first began to make things out of lacquer, the colored red sap of the lac tree painted onto wood. They used lacquer to make beautiful light-weight boxes, dishes, and even small statuettes. And at the end of the Eastern Chou period, about 300 BC, people also began to paint scenes with people and landscapes onto silk.

Natural cycles

       The exchange of substances are very much essential for life on the Earth. The substances, such as Nitrogen and Carbon are constantly changing their forms when they move in their cycles. All the things, such as air, land, animals, plants, human beings, water, etc. are a part of these cycles.

1. How is the balance of gases in the air maintained?
       The living things take in oxygen, nitrogen and carbon and water from the surroundings through food, air and soil. They use them for their growth and development. When the living things, such as plants and animal die, their body decays and these bodies are broken down and gas is released in the air. This process continues again and again. Thus, the balance of gas in the air is maintained.

2. Briefly describe the nitrogen cycle.
       The major percentage of gas present in the air is Nitrogen. It is about 78% of the air. The plants and animals need nitrogen for their growth and development. Plants take in nitrogen from the soil and the air. The animals obtain nitrogen by eating plants or by eating animals, who have eaten plants. When the plants and animals die, they decay and the bacteria as well as fungi break down their remains and release nitrogen back into the soil.

3. Briefly describe the carbon cycle.
       Carbon is a part of the gas called carbon dioxide or, in other words we can say, carbon dioxide is a compound of carbon and oxygen. The plants take in carbon dioxide from the air and use it to manufacture their food by the process of photosynthesis. Animals obtain carbon by eating plants. Animals give out or breathe out carbon dioxide. Carbon dioxide is also released when animals and plants die and decay. At last, after decaying, they form fossil fuels, such as coal, coke, etc.

4. How does farming affect the Nitrogen cycle?
       When the farmers harvest crops, they remove plants, which have taken in nitrates from the soil. As the plants are not allowed to decay naturally, the nitrogen is not returned to the soil and the nitrogen cycle is broken.

5. What are greenhouse gases?
       The Earth’s surface absorbs some of the heat from the sun, but the rest is bounced back into the atmosphere. Most of it escapes into the space, but some is trapped in the atmosphere by gases known as greenhouse gases. The main greenhouse gases are carbon dioxide and water in the form of clouds. As the amount of greenhouse gases increase, more heat is trapped.

6. What is greenhouse effect?
       Some of the gases in the atmosphere help to keep the Earth warm. They trap heat from the sun in the same way that a greenhouse traps heat. This process is known as the greenhouse effect.

7. What is global warming?
       The industrial processes and other kinds of pollution are increasing the amount of greenhouse gases in the atmosphere. This causes the Earth to become warmer. This process is called global warming.

What is Cartilage?

       Cartilage is a smooth, tough but flexible part of the body’s skeleton system. All cartilage is made of matrix, which consist of fibres made of proteins.

       It is found in several parts of the body, such as the outer part (pinna) of the ear, the tip of the nose, the larynx and the wind pipe.

       Cartilage is found in all movable joints where it helps to reduce friction and acts as a shock absorber.

       According to their different physical properties, there are various types of cartilages like elastic cartilage, hyaline cartilage etc. Unlike bone, cartilage has no blood supply and does not repair itself when damaged. Cartilage is found in the skeleton where its toughness, smoothness and flexibility are most needed. Cartilage is composed of matrix in which fibres made of proteins called collagen are found.

Why does lightning strike?

       Lightning is the visible electric discharge that takes place among the rain clouds or between the rain clouds and the earth. The process of lightning can be best understood if we remember the fact about electricity. We know that things become electrically charged positively or negatively. The positive charge has attraction for the negative charge.
                                          Lightning
       This attraction increases as the charge becomes greater. Finally, a point arrives when the strain of keeping the two charges apart becomes too great. This is the point when discharge takes place and the strain is relieved. It makes the two bodies electrically equal. In the case of lightning also, the same thing happens. The visible discharge of lightning follows the path that has less resistance. It is for this reason that the lightning is seen in a zigzag formation. Humid air is a fair conductor of electricity. Therefore, lightning ceases as soon as it starts raining. Rain clouds are negatively charged at upper end and positively charged at lower end.

Fact
       Ball lightning is an exceptional occurrence in the form of a slow moving, shining ball that sometimes explodes.