Kids Learning Science V Term-I

5th Standard Science Term-I

Matter and Materials

Our needs have increased in the modern days and we use a number of things in our daily life.  We get some of them from the nature and some of them are manufactured artificially.  The things you use like pen, pencil, ink, eraser, note book, ball and the food you eat, all have different nature and characteristics.  They are obtained by transforming the natural and artificial substances.  In this lesson we will study about different things used in our life and how they are obtained.

Matter is anything that has mass and occupies space.  Matter can exist in three physical states : solid, liquid and gas.  It is made up of molecules and the molecules are made up of atoms.

✧ Solid 

In solids, molecules are very closely packed.  Solids are incompressible.  They have definite shape, size and volume.

✧ Liquid

In liquids, molecules are loosely packed.  Hence, liquids are negligibly compressible.  They have definite volume, but no definite shape and size.

✧ Gas

In gases, molecules are very loosely packed.  Hence, gases are highly compressible.

A material is a mixture of substances that constitute an object.  They can be pure or impure, natural or man made.  Materials are required to get the things needed for our daily life.  We need food, dress and many other goods for our daily living.  Natural and man made materials are transformed to produce these things.

Fibre is a thin thread of natural or artificial substances.  It is used to make cloths with the help of power looms or weaving machines.  The fibres we get from plants and animals are called natural fibres.  Cotton, jute, coir and flax are examples for plant fibres.  Wool and silk are examples for animal fibres.  Fibres made by humans by chemical synthesis are called synthetic fibres or artificial fibres.  Rayon, nylon, acrylic and dacron are examples for artificial fibres.  These fibres are obtained from petroleum by complex chemical processes.

✧ Cotton

A cotton plant is a bushy plant of 5 to 6 feet high.  Cotton grows well in black soil and alluvial soil.  The cotton plant bears a large number of small green pods called cotton balls.  These balls contain seeds covered with white fibres.  When the cotton balls mature, they burst exposing the white fibre of cotton.  Cotton is usually hand picked from the plants.

Ginning

There are two processes to make cotton yarn from cotton fibre.  They raw fibres are separated from the seeds by a process known as ginning.  The fibrous material left after separating cotton seeds is called lint.  The lint is then tied and pressed into balls.  The final proportions of short fibres and other impurities are removed by the process of combing.

Spinning

The process of making yarn from lint (fibre) is called spinning.  Spinning is done on a large scale with the help of spinning machines.

Yarn to fabrics

Weaving and knitting are the two most important processes used for making fabric from the yarn.  The process of making two sets of yarns together to make fabric is called weaving.  It is done by weavers on a machine called loom.  The looms are either hand - operated (hand looms) or power - operated (power looms).  During knitting a single yarn is used to make a piece of fabric.  It is done by hand and also on machine.

Uses of Cotton

➜ It is used to manufacture cotton textiles and garments.

➜ It is used as fillers in pillows and mattresses.

➜ It is used for making surgical bandages.

➜ It is used for making dhotis, sarees, bedsheets, table cloth and so on.

✧ Jute

Jute fibre is obtained from the stem of the jute plant.  Jute plant has long, soft and shiny fibres.  It is also known as golden fibre due to its colour and cost effectiveness.  Jute fibres are separated from the process of retting jute by hand and then they are dried.  These are converted into yarns in the same manner as in the case of cotton.

Uses of Jute

➜ It is used for making bags, carpets, curtains and ropes.

➜ It is used for making cloths for wrapping bales of raw cotton and to make sacs for storing grains.

➜ It is used for making wall hangings for decoration.

✧ Coir

Coir fibre is obtained from the outer covering of coconut.  It is used to make floor mats, door mats, brushes and mattresses.

These fibres are made by human beings with the help of chemical process.  Hence, they are called synthetic fibres or manmade fibres.  These fibres are obtained from coal, petroleum and natural gas. 

Synthetic fibre	Sources
Rayon	Wood pulp
Nylon	Coal
Polyester	Petroleum products
Acrylic	Natural gas

 

Uses of Synthetic Fibres

➜ Rayon is used to make rope, cloth, cap, tyre cords and carpets.

➜ Nylon is used to make fishing nets ropes, parachutes, fabrics and bristles for brushes.  

➜ Polyester is used to make fabric for suits and shirts, hoses, conveyor belts, films, PET bottles and wires.

➜ Acrylic is used to make sweaters, shawls and blankets.

Grain is a small, had, dry seed.  Each grain is protected by a husk and the husk encloses the seed.  Two main types of commercial grain crops are cereals and legumes.  Wheat, maize, rice, beans, peas, barley and millets are some of the whole grains.

✧ Wheat

This is the most important crop in the world.  Whole wheat is important because it is rich in fibre, vitamins and minerals.  Wheat products are breads, cakes, pasta, wheat germ and cracked wheat.

✧ Maize

In many tropical and sub tropical countries (Mexico and America) Maize is the main food that people eat.  It is also known as corn.  Maize oil is extracted from corn for cooking.  Yellow or coloured corn may promote eye health.  It is also a rich source of many vitamins and minerals.  Corn syrup is used as a sweetener instead of sugar in many products.  Maize products are sweet corn, breakfast cereal, tortilla chips, taco and maize oil.

✧ Rice

Rice is a type of grass.  It is cultivated worldwide after sugarcane and maize.  Large parts of the world's human population especially people in Asia have this as their main food.  Ninety percent of the world's rice production is in Asia.  White rice contains few essential nutrients.  Brown rice is a whole grain that contains the fibrous bran.  Brown rice is usually considered much healthier than white rice.  Rice idly, idiappam and rice aval (flattened rice) are the food items prepared from rice.

                                      

✧ Millets

Millets are a group of small seeded grasses.  They are widely grown around the world as cereal crops for fodder and human food.  It helps in weight loss.  It is rich in fibre.  Some of the millets are sorghum, foxtail millet, finger millet, pearl millet, barnyard millet, kodo millet and little millet.

                                 

These are the products that we use in our houses.  The things that are found in or houses permanently are called household things.  House hold things are furniture, kitchenware, clothes, towels, beddings, boots and electronic goods etc.

Household things used in the olden days

Household things used in the modern days

You could have seen that some objects float in water while others sink.  Whether an object floats or sinks in water is determined by its density.  When an object is immersed into a liquid, the liquid exerts an upward force on the object.  It is known as upthrust.  What happens if you put a coin and an empty water bottle in water?  The weight of the coin is greater than the upthrust and so the coin sinks.  But the weight of the empty water bottle is less than the upthrust and so it floats.

Some substances completely dissolve in water.  We say that these substances are soluble in water.  Other substances do not dissolve in water even after we stir for long time.  These substances are insoluble in water.

Certain liquids are denser than other liquids.  When you attempt to mix liquids which have different densities they separate when you stop mixing them.  The heavier liquid deposits at the bottom and the lighter liquid floats on the top.