Definitions of Famous Scientific Terms

1.       Matter

Ans. The substances which we can see , touch and feel are called Matters.

 

2.       Mass

Ans.  The mass of a body is a measure of the quantity of in the body.

 

3.       Density

Ans.  The density if a substance is the mass per unit volume.

 

4.       Volume

Ans. The space occupied by a body is called Volume.

 

5.       Speed

Ans. The distance travelled by an object in an unit-time is called Speed.

 

6.       Velocity

Ans. It is the distance travelled by an object in a given direction in an unit-time is called Velocity.

 

7.       Force

Ans. A force is that which changes or tends to change the state of rest or motion of a body .

 

8.       Weight

Ans. The weight of a body is the force with which the earth attracts the body towards itself.

 

9.       Gravity

Ans. The force between the earth and an object is called the Gravity.

 

10.    Force of Gravitation

Ans. The force between the two heavenly bodies id called Force of Gravitation.

 

11.    Energy

Ans. The capacity of doing work of an object is called its energy.

 

12.    Work

Ans. When an object is acted by a force and there is a displacement of that object in the same direction , then it is said that the work has been done.

 

13.    Power

Ans. The work done in an unit-time is called Power.

 

14.    Specific Gravity

Ans. It is the ratio of the weight of any volume of substance to the weight of an equal volume of water at 4 degree Celcius.

 

15.    Heat

Ans. It is a form of energy that produces the sensation of warmth.

 

16.    Light

Ans. It is a form of energy and also electromagnetic radiation that causes the sensation of vision.

 

17.    Sound

Ans.  It is a form of energy which is produced by vibrations.

 

18.    Element

Ans. Element is the purest form of matter which can not be divided into two or more than two different substances which have different properties.

 

19.    Mixture

Ans. It is formed with the mixing of two or more than two elements in indefinite ratio. By simple method its constituents can be separated.

 

20.    Compound

Ans. A compound id formed by the chemical raction of two or more than two elements in a definite ratio . Its constituents can be separated by chemical method.

 

21.    Liquification

Ans. The change of state from solid to liquid is called liquification.

 

22.    Boiling Point

Ans. The temperature at which the liquid boils is called its Boiling point.

 

23.    Physical Change

Ans. In this change , the state of a substance changes for a while but it regains its formal state again.

 

24.    Chemical Change

Ans.  In this change,the chemical properties changes permanently and it does not regain its formal state.

 

25.    Acids

Ans. Acids are those substances which taste our sour and turn blue litmus paper into red.

 

26.    Base

Ans. It is an oxide or hydroxide of a metal . Its taste is sour and turn red litmus paper into blue.

 

27.    Sublimation

Ans. In this chemical action when a solid substance is heated , it directly converts into gas without converting into liquid and when it is cooled down , it is directly converted into solid without converting into liquid.

 

28.    Catalysis

Ans.  The substance which is responsible for the increase and decrease of the rate of a Chemical reaction is called catalyst and this phenomena is called Catalysis.

 

29.    Oxidation

Ans. The combination of a substance with oxygen and removal of hydrogen from the substance is called Oxidation.

 

30.    Reduction

Ans. The removal of oxygen from the substance and addition of hydrogen is called Reduction .

 

31.    Atom

Ans.  Smallest particle of an element which does not occur in free state but takes part in chemical reaction.

 

32.    Molecule Ans. It is the smallest particle of an or compound which occurs in free state but does not take part in chemical reaction.

 

33.    Ores

Ans. Ores are the substances from which metals are extracted .

 

34.    Living things

Ans. The substances which has life , are known as Living things.

 

35.    Non-living things

Ans. The substances which has no life , are called Non-living things.

 

36.    Cell

Ans. Cell is the structural , functional and hereditary unit of life.

 

37.    Tissue

Ans. A group of cells that work together to perform a specific function.

 

38.    Liver

Ans. It is a gland of human body , which is situated at the right side above the abdomen.

 

39.    Gall-bladder

Ans. It is situated at the bottom of the liver .It is pear shaped small bag which is called Gall-bladder.

 

40.    Pancreas

Ans. It is both the ductless as well as ductfull gland whose one part is known as Islets of Langerhans . It secrets hormones named Insulin and Glucon.

 

41.    Vein

Ans. Veins are the blood-vessels which carry the impure blood to the heart.

 

42.    Artery

Ans. It carries the pure blood to the different parts of the body.

 

43.    Blood-pressure

Ans. It is the pressure exerted by the blood for the proper blood-circulation . When the pressure is more or less than the normal, it causes the high or low blood-pressure respectively.

 

44.    Haemoglobin

Ans. It is a red coloured pigment which exchanges oxygen and carbon dioxide in the blood.

 

45.    Pencilin

Ans. It is an antibiotic medicine which kills bacteria.