Matter Around Us Online Test 6th Science Lesson 3 Questions in English

Matter is all around us. The air you are breathing is also a matter. Matter is defined as anything that has mass and takes up space. Matter is found in three major states; solid, liquid and gas. All matter is made of atoms. Atoms are the smallest particle of matter.

Science has come up with a technology to identify structure of atoms Scanning Electron Microscope (SEM) and Tunnelling Electron Microscope (TEM) which uses electricity to map atoms.

Silicon atoms on a surface can be viewed through the Scanning Tunnelling Microscopy, (STM).

Plasma is not a common state of matter on Earth, but may be the most common state of matter in the universe. For example, stars including sun are covered in plasma.

Besides solids, Liquid and gases there are two more states plasma and Bose – Einstein condensates.

Bose – Einstein condensate was predicted around 1925 and confirmed in 1995, This is used in the field of cryogenics.

Bose – Einstein condensate is a gas – like state of matter that exists at extremely cold temperatures.

Matter occupies space and has mass. Ancient philosophers pondered over such questions. In India a philosopher named Kanada and in Greece a philosopher named Democritus came to somewhat similar idea.

Particles of matter have a lot of space in between them. In different forms of matter this spacing will be different.

We may conclude that the particles of gases and liquids can move and that among gases more easily. We call this movement as diffusion. Diffusion is the tendency of particles to spread out in order to occupy the available space.

In solid, the particles are tightly packed with very little space between them. Eg. Stone. Particles in liquids are arranged in a random or irregular way and the space between the particles is greater than that in solids Eg. Water

Liquid atoms are packed more loosely which allows things to be able to pass through it. Liquid is effected by gravity more than anything. Liquids are always moving due to gravity around it.

Gas atoms are spread out so far, you can walk through it without any restriction. Gas is not affected by gravity. The gas’s atoms never stop moving and it never stays in place.

Movement of particles is restricted in solids and they do not diffuse like liquids or gases. In fluids the particles are under motion and hence can push ink or smoke particles here and there.

“Liquefaction of gases” is the process by which substances in their gaseous state are converted to the liquid state. When pressure on a gas in increased, its molecules comes closer together, and its temperature is reduced, which removes enough energy to make it change from the gaseous to the liquid state.

A pure substance is made up of only one kind of particles. Pure substances may be elements or compounds.

Purity of gold is expressed in terms of ‘carat’. 24 carat gold is considered to be gold in its purest form.

Air is a mixture because it contains Oxygen, Nitrogen, Carbon dioxide, water vapour, noble gases etc. Milk is also a mixture of water, fat, protein etc.

When elements chemically combine they form compounds; whereas a mixture can be a physical combination of two or more elements. Example: 22 carat gold which is composed of gold and copper / gold and cadmium.

A sieve is similar to a strainer. Sieving is used when we have to separate solid particles of different sizes. Eg: bran from flour, sand from gravel etc.

When very fine insoluble solids have to be separated from a liquid as in butter from curds, Churning is performed. The mixture is churned vigorously when solid butter will be collected on the sides of the vessel. Both butter and buttermilk are obtained after churning are useful and can be consumed.

In washing machines Churning principle is used to squeeze out dirt from clothes and the method is called centrifugation.

Farmers separate grains from their stalks by beating them so hard that the grains are separated from their stalks. This is called Threshing.

Rice, wheat and other food grains are covered in husk which cannot be eaten by us. Husk is very light and gets easily blown away by a breeze or wind.

Rice, wheat and other food grains are covered in husk which cannot be eaten by us. Husk is very light and gets easily blown away by a breeze or wind. This property is made use of in winnowing. This is done by dropping the mixture slowly from a height in the presence of wind. Lighter solids i.e. husks will be carried by wind and will be collected in a separate heap while heavier solids i.e. grains will fall closer and form a separate heap.

Rice husks are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, husks can be used as building material, fertilizer, insulation material and fuel.

In a mixture containing iron, the magnetic property of iron can be used to separate it from non- magnetic substances by using a magnet. Substances that are attracted to a magnet are called magnetic. Separating solids using a magnet is called magnetic separation.

The rice or pulses are washed in water. The lighter impurities float while heavier rice grains sink to the bottom. This is called sedimentation. The water with the impurities is carefully poured away leaving clean rice at the bottom. This is called decantation.

Decantation process is done after sedimentation. The supernatant liquid is slowly poured out from the container without disturbing the sediment.

The process of removal of water above the sediment is called decantation. But even after decantation the water is not completely free from fine soil particles.

A filter paper has very fine pores much smaller than soil particles. The liquid which passes through the filter and comes down is called filtrate.

The liquid which passes through the filter and comes down is called filtrate and the insoluble component left behind on the filter is called residue.

In most houses people use commercial water filter to remove not only the impurities but also to kill the harmful germs in water using UV rays.

An adulterated substance will not indicate the true properties of the original substance. For example: Used tea leaves are sometimes used as adulterants in tea. Turmeric powder is adulterated with a bright yellow chemical which is poisonous to our health.