Matter in Our Surroundings : āĻāĻŽāĻžā§° āĻāĻžā§°āĻŋāĻāĻāĻžāώ⧰ āĻĒāĻĻāĻžā§°ā§āĻĨ : Question with Answer
1. āϤāϞ⧰ āĻā§āύāĻŦā§ā§° āĻĒāĻĻāĻžā§°ā§āĻĨ ? Science 9th : Ass / Eng
āĻāĻā§, āĻŦāĻžāϝāĻŧā§, āĻŦāĻžāĻĻāĻžāĻŽ, āĻ āĻžāĻŖā§āĻĄāĻž-āĻĒāĻžāύā§āϝāĻŧ, āϏā§āĻāύā§āϧāĻŋ āĻĻā§ā§°āĻŦā§āϝ⧰ āϏā§āĻŦāĻžāϏ, āĻĒā§ā§°ā§āĻŽ, āĻā§āĻŖāĻž, āĻāĻŋāύā§āϤāĻž, āĻ āĻžāĻŖā§āĻĄāĻž, āĻā§āύā§āϧ
Ans:āĻĒāĻĻāĻžā§°ā§āĻĨ: āĻāĻā§, āĻŦāĻžāϝāĻŧā§, āĻŦāĻžāĻĻāĻžāĻŽ, āĻ āĻžāĻŖā§āĻĄāĻž-āĻĒāĻžāύā§āϝāĻŧ, āϏā§āĻāύā§āϧāĻŋ āĻĻā§ā§°āĻŦā§āϝ⧰ āϏā§āĻŦāĻžāϏ, āĻĒāĻĻāĻžā§°ā§āĻĨ āύāĻšāϝāĻŧ: āĻĒā§ā§°ā§āĻŽ, āĻā§āĻŖāĻž, āĻāĻŋāύā§āϤāĻž, āĻ āĻžāĻŖā§āĻĄāĻž, āĻā§āύā§āϧ
āĻāĻžā§°āĻŖ: āϝāĻŋāĻŦā§ā§° āĻŦāϏā§āϤā§ā§° āĻā§° āĻĨāĻžāĻā§ āĻā§°ā§ āĻ āĻžāĻ āϞāϝāĻŧ, āϏā§āĻāĻŦā§ā§° āĻĒāĻĻāĻžā§°ā§āĻĨāĨ¤ āĻ āύā§āĻā§āϤāĻŋ āĻā§°ā§ āϧāĻžā§°āĻŖāĻž āĻĒāĻĻāĻžā§°ā§āĻĨ āύāĻšāϝāĻŧāĨ¤
1. Which of the following are matter ?
Chair, Air, Love, Smell, Hate, Peanuts, Thoughts, Cold, Cold drink, Fragrance of perfume
Ans: Matter: Chair, Air, Peanuts, Cold drink, Fragrance of perfume. Not Matter: Love, Hate, Thoughts, Cold, Smell
Reason: Matter has mass and occupies space. Feelings and ideas are not physical substances.
2. āĻāϤā§āϤāĻĒā§āϤ āĻŦāϏā§āϤā§ā§° āĻā§āύā§āϧ āĻĻā§ā§°āϞ⧠āĻāĻŋāϝāĻŧ āϝāĻžāϝāĻŧ ?
Ans: āĻāϤā§āϤāĻĒā§āϤ āĻŦāϏā§āϤā§ā§° āĻā§āύā§āϧ āĻĻā§ā§°āϞ⧠āϝāĻžāϝāĻŧ āĻāĻžā§°āĻŖ āĻāώā§āĻŖāϤāĻž āĻŦāĻžāĻĸāĻŧāĻŋāϞ⧠āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§°ā§° āĻāϤāĻŋ āĻŦāĻžāĻĸāĻŧā§ āĻā§°ā§ āĻŦā§āϝāĻžāĻĒāύ (diffusion) āĻĻā§āϰā§āϤ āĻšāϝāĻŧāĨ¤
2. Why smell spreads faster in hot objects ?
Ans: Smell spreads faster from hot objects because higher temperature increases particle motion, which increases diffusion rate.
3. āĻĄā§āĻŦāĻžā§°ā§ā§ąā§ āĻĒāĻžāύ⧠āĻĢāĻžāϞāĻŋ āĻā§āύā§āĻā§ āϏā§āĻŽāĻžāĻŦ āĻĒāĻžā§°ā§ ?
Ans: āĻĄā§āĻŦāĻžā§°ā§ā§ąā§ āĻĒāĻžāύ⧠āĻĢāĻžāϞāĻŋ āϏā§āĻŽāĻžāĻŦ āĻĒāĻžā§°ā§ āĻāĻžā§°āĻŖ āĻĒāĻžāύā§ā§° āĻāĻŖāĻŋāĻāĻžā§° āĻŽāĻžāĻāϤ āĻĢāĻžāĻāĻ āĻĨāĻžāĻā§ āĻā§°ā§ āϏāĻŋāĻšāĻāϤ āϏāĻšāĻā§ āϏ⧰āĻāĻŋ āϝāĻžāϝāĻŧāĨ¤
3. Why can a diver pass through water ?
Ans:A diver can pass through water because water particles have spaces between them and can easily move aside.
4. āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻŋāĻāĻžā§° āĻŦā§āĻļāĻŋāώā§āĻā§āϝāϏāĻŽā§āĻš āĨ¤
Ans: 1. āĻ āϤāĻŋ āĻā§āώā§āĻĻā§ā§° āĻāĻŖāĻŋāĻāĻž 2. āĻŽāĻžāĻāϤ āĻĢāĻžāĻāĻ āĻĨāĻžāĻā§ 3. āϏāĻĻāĻžāϝāĻŧ āĻāϤāĻŋ āĻā§°ā§ 4. āĻāĻāϰā§āώāĻŖ āĻŦāϞ āĻĨāĻžāĻā§ 5. āĻāώā§āĻŖāϤāĻžāϤ āĻāϤāĻŋ āĻŦāĻžāĻĸāĻŧā§
4. Characteristics of particles of matter.
Ans: 1. Very small particles 2. Have space between them 3. Always in motion 4. Attract each other 5. Speed increases with temperature
============================================== Science 9th : Ass / Eng
1. āϤāϞ⧰ āĻĒāĻĻāĻžā§°ā§āĻĨāĻŦā§ā§° āĻāύāϤā§āĻŦā§° āĻā§°ā§āϧā§āĻŦāĻā§āϰāĻŽāϤ āϏāĻā§ā§ąāĻžāĨ¤ (Arrange the following substances in increasing order of density.)
āĻŦāĻžāϝāĻŧā§, āĻāĻŋāĻŽāύāĻŋā§° āĻĒā§°āĻž āĻāϞā§ā§ąāĻž āϧā§āĻā§ąāĻž, āĻŽā§, āĻĒāĻžāύā§, āĻāĻāĻŽāĻžāĻāĻŋ, āĻāĻĒāĻžāĻš āĻā§°ā§ āϞā§āĨ¤ (Air, smoke from chimney, honey, water, chalk, cotton and iron.)
āĻāϤā§āϤ⧰ / Ans: āĻāĻŋāĻŽāύāĻŋā§° āĻĒā§°āĻž āĻāϞā§ā§ąāĻž āϧā§āĻā§ąāĻž < āĻŦāĻžāϝāĻŧā§ < āĻāĻĒāĻžāĻš < āĻĒāĻžāύ⧠< āĻŽā§ < āĻāĻāĻŽāĻžāĻāĻŋ < āϞ⧠(Smoke from chimney < Air < Cotton < Water < Honey < Chalk < Iron)
2(a). āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻŦāĻŋāĻāĻŋāύā§āύ āĻ ā§ąāϏā§āĻĨāĻžā§° āĻŦā§āĻļāĻŋāώā§āĻā§āϝāĻŦā§ā§°ā§° āĻĒāĻžā§°ā§āĻĨāĻā§āϝ āĻĻā§āĻā§ā§ąāĻžāĻ āĻāĻāύ āϤāĻžāϞāĻŋāĻāĻž āĻā§°āĻžāĨ¤ (Differentiate between the three states of matter.)
āĻāϤā§āϤ⧰ / Ans: āĻāĻ āĻŋāύ āĻĒāĻĻāĻžā§°ā§āĻĨā§° āύāĻŋāϰā§āĻĻāĻŋāώā§āĻ āĻāĻā§āϤāĻŋ āĻā§°ā§ āĻā§āϤāύ āĻĨāĻžāĻā§āĨ¤ āĻā§āϞā§ā§āĻž āĻĒāĻĻāĻžā§°ā§āĻĨā§° āύāĻŋāϰā§āĻĻāĻŋāώā§āĻ āĻā§āϤāύ āĻāĻā§ āĻāĻŋāύā§āϤ⧠āĻāĻā§āϤāĻŋ āύāĻžāĻāĨ¤ āĻā§āĻā§ā§ āĻĒāĻĻāĻžā§°ā§āĻĨā§° neither āύāĻŋāϰā§āĻĻāĻŋāώā§āĻ āĻāĻā§āϤāĻŋ nor āĻā§āϤāύ āĻĨāĻžāĻā§āĨ¤ āĻāĻ āĻŋāύ⧰ āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§° āĻāύāĻā§ āϏāĻā§āĻāĻŋāϤ āĻĨāĻžāĻā§, āĻā§āϞā§ā§āĻžāϤ āĻŽāϧā§āϝāĻŽā§ā§āĻž āĻā§°ā§ āĻā§āĻā§ā§āϤ āĻŦāĻšā§āϤ āĻĻā§ā§°āϤ āĻĨāĻžāĻā§āĨ¤ āĻā§āĻā§° āĻāϤāĻŋāĻļāĻā§āϤāĻŋ āĻāĻāĻžāĻāϤāĻā§ āĻŦā§āĻāĻŋāĨ¤
Solids have fixed shape and fixed volume. Liquids have fixed volume but no fixed shape. Gases have neither fixed shape nor fixed volume. The particles in solids are closely packed, in liquids moderately spaced, and in gases far apart. Gases have the highest kinetic energy.
2(b). āϤāϞ⧰ āĻŦāĻŋāώā§āĻŦā§ā§°ā§° āĻāĻĒā§°āϤ āĻŽāύā§āϤāĻŦā§āϝ āĻĻāĻŋā§āĻžāĨ¤ (Comment on the following.)
āĻĻā§ā§āϤāĻž (Rigidity): āĻāĻ āĻŋāύ āĻĒāĻĻāĻžā§°ā§āĻĨ āϏāĻšāĻā§ āĻāĻā§āϤāĻŋ āϏāϞāύāĻŋ āύāĻā§°ā§āĨ¤ (Solids cannot change shape easily.)
āϏāĻāĻā§āĻāύāĻļā§āϞāϤāĻž (Compressibility): āĻā§āĻ āϏāĻšāĻā§ āϏāĻāĻā§āĻāĻŋāϤ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋ, āĻāĻŋāύā§āϤ⧠āĻāĻ āĻŋāύ āϏāĻšāĻā§ āϏāĻāĻā§āĻāĻŋāϤ āύāĻšā§āĨ¤ (Gases can be compressed easily, but solids cannot.)
āĻĒā§āϰāĻŦāĻžāĻšāĻŋāϤāĻž (Fluidity): āĻā§āϞā§ā§āĻž āĻā§°ā§ āĻā§āĻā§ā§ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŦā§ āϝāĻžāĻŦ āĻĒāĻžā§°ā§āĨ¤ (Liquids and gases can flow.)
āĻāĻāĻžā§° (Shape): āĻāĻ āĻŋāύ⧰ āύāĻŋāϰā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āĻĨāĻžāĻā§, āĻāĻŋāύā§āϤ⧠āĻā§āϞā§ā§āĻž āĻā§°ā§ āĻā§āĻā§ā§ā§° āύāĻžāĻĨāĻžāĻā§āĨ¤ (Solids have fixed shape, but liquids and gases do not have fixed shape.)
āĻāϤāĻŋāĻļāĻā§āϤāĻŋ (Kinetic Energy): āĻā§āĻā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§°ā§° āĻāϤāĻŋāĻļāĻā§āϤāĻŋ āĻāĻāĻžāĻāϤāĻā§ āĻŦā§āĻāĻŋāĨ¤ (Gas particles have the highest kinetic energy.)
āĻāύāϤā§āĻŦ (Density): āĻāĻ āĻŋāύ āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāύāϤā§āĻŦ āϏāĻžāϧāĻžā§°āĻŖāϤ⧠āĻŦā§āĻāĻŋāĨ¤ (Solids generally have high density.)
3(a). āĻā§āύ⧠āĻāĻāĻž āĻŦāύā§āϧ āĻĒāĻžāϤā§ā§°āϤ āĻā§āĻ ā§°āĻžāĻāĻŋāϞ⧠āϏā§āĻ āĻā§āĻā§ āĻĒāĻžāϤā§ā§°āĻā§ā§° āϏāĻāϞ⧠āĻ āĻāĻļ āĻ āϧāĻŋāĻāĻžā§° āĻā§°ā§ āĻāĻŋā§ ? (Why does gas occupy the whole container ?)
āĻāϤā§āϤ⧰ / Ans: āĻā§āĻā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§°ā§° āĻŽāĻžāĻāϤ āĻ āϧāĻŋāĻ āĻĢāĻžāĻāĻ āĻĨāĻžāĻā§ āĻā§°ā§ āϏāĻŋāĻšāĻāϤ āϏāĻāϞ⧠āĻĻāĻŋāĻļāϤ āϏā§āĻŦāĻžāϧā§āύāĻāĻžā§ąā§ āĻāϤāĻŋ āĻā§°ā§āĨ¤ āϏā§ā§ā§ āĻā§āĻā§ āĻĒāĻžāϤā§ā§°āĻā§ā§° āϏāĻāϞ⧠āĻ āĻāĻļ āĻ āϧāĻŋāĻāĻžā§° āĻā§°ā§āĨ¤ (Gas particles have large spaces between them and move freely in all directions. Therefore, gas occupies the whole container.)
3(b). āϧāĻžā§°āĻ āĻĒāĻžāϤā§ā§°ā§° āĻŦā§ā§°āϤ āĻā§āĻā§ āĻāĻžāĻĒ āĻĻāĻŋā§ā§ āĻāĻŋā§ ? (Why does gas exert pressure on the walls of the container ?)
āĻāϤā§āϤ⧰ / Ans: āĻā§āĻā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§° āϏāĻĻāĻžā§ āĻāϤāĻŋ āĻā§°āĻŋ āĻĨāĻžāĻā§ āĻā§°ā§ āĻĒāĻžāϤā§ā§°ā§° āĻŦā§ā§°āϤ āĻā§āύā§āĻĻāĻž āĻŽāĻžā§°ā§āĨ¤ āĻāĻ āĻā§āύā§āĻĻāĻžā§° āĻĢāϞāϤā§āĻ āĻāĻžāĻĒ āĻā§āĻĒāύā§āύ āĻšā§āĨ¤ (Gas particles continuously move and collide with the walls of the container. These collisions produce pressure.)
3(c). āĻāĻžāĻ ā§° āĻā§āĻŦā§āϞ āĻāĻāύāĻ āĻāĻ āĻŋāύ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŦā§āϞāĻŋāĻŦ āĻĒāĻžā§°āĻŋ āĻāĻŋā§ ? (Why is a wooden table called a solid ?)
āĻāϤā§āϤ⧰ / Ans: āĻāĻžāĻ ā§° āĻā§āĻŦā§āϞ⧰ āύāĻŋāϰā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āĻā§°ā§ āĻā§āϤāύ āĻāĻā§āĨ¤ āĻā§āĻžā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§° āĻāύāĻā§ āϏāĻā§āĻāĻŋāϤ āĻĨāĻžāĻā§āĨ¤ āϏā§ā§ā§ āĻ āĻāĻ āĻŋāύ āĻĒāĻĻāĻžā§°ā§āĻĨāĨ¤ (A wooden table has fixed shape and fixed volume. Its particles are closely packed. Therefore, it is a solid.)
3(d). āĻŦāĻžāϝāĻŧā§āϤ āĻāĻŽāĻžā§° āĻšāĻžāϤ āϏāĻšāĻā§ āĻā§ā§°āĻžāĻŦ āĻĒāĻžā§°ā§ āĻāĻŋāύā§āϤ⧠āĻāĻžāĻ ā§° āĻŽāĻžāĻā§ā§°ā§ āύā§ā§ąāĻžā§°ā§ āĻāĻŋā§ ? (Why can we move our hand easily in air but not through wood ?)
āĻāϤā§āϤ⧰ / Ans: āĻŦāĻžāϝāĻŧā§ā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§°ā§° āĻŽāĻžāĻāϤ āĻ āϧāĻŋāĻ āĻĢāĻžāĻāĻ āĻĨāĻžāĻā§āĨ¤ āĻāĻŋāύā§āϤ⧠āĻāĻžāĻ ā§° āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§° āĻāύāĻā§ āϏāĻā§āĻāĻŋāϤ āĻĨāĻžāĻā§āĨ¤ āϏā§ā§ā§ āĻŦāĻžāϝāĻŧā§āϤ āĻšāĻžāϤ āϏāĻšāĻā§ āĻā§ā§°āĻžāĻŦ āĻĒāĻžā§°ā§ āĻāĻŋāύā§āϤ⧠āĻāĻžāĻ ā§° āĻŽāĻžāĻā§ā§°ā§ āύā§ā§ąāĻžā§°ā§āĨ¤ (Air particles have large spaces between them, whereas wood particles are tightly packed. Therefore, we can move our hand easily in air but not through wood.)
4. āĻŦā§°āĻĢ āĻĒāĻžāύā§āϤ āĻāĻĒāĻāĻŋ āĻĨāĻžāĻā§ āĻāĻŋā§ ? (Why does ice float on water ?)
āĻāϤā§āϤ⧰ / Ans: āĻŦā§°āĻĢā§° āĻāύāϤā§āĻŦ āĻĒāĻžāύā§āϤāĻā§ āĻāĻŽāĨ¤ āϏā§ā§ā§ āĻŦā§°āĻĢ āĻĒāĻžāύā§ā§° āĻāĻĒā§°āϤ āĻāĻĒāĻāĻŋ āĻĨāĻžāĻā§āĨ¤ (Ice is less dense than water. Therefore, ice floats on water.)
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Introduction to Matter : āĻāĻŽāĻžā§° āĻāĻžā§°āĻŋāĻāĻāĻžāώ⧰ āĻĒāĻĻāĻžā§°ā§āĻĨ - āĻ āĻāĻļ ā§§ : āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻĒā§°āĻŋāĻāϝāĻŧ
What is Matter ? :: āĻĒāĻĻāĻžā§°ā§āĻĨ āĻāĻŋ ? Science 9th : Ass / Eng
Matter is anything that has mass and occupies space.. āϝāĻŋ āĻŦāϏā§āϤā§ā§° āĻā§° (mass) āĻāĻā§ āĻā§°ā§ āϏā§āĻĨāĻžāύ āĻĻāĻāϞ āĻā§°ā§, āϤāĻžāĻ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŦā§āϞāĻž āĻšāϝāĻŧāĨ¤
Examples of Matter :: āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻĻāĻžāĻšā§°āĻŖ
- Ice cube - has mass and shape. āĻŦā§°āĻĢā§° āĻā§āĻā§ā§°āĻž - āĻā§° āĻā§°ā§ āĻāĻāĻžā§° āĻāĻā§
- Wooden block - occupies space. āĻāĻžāĻ ā§° āĻā§āĻā§ā§°āĻž - āϏā§āĻĨāĻžāύ āĻĻāĻāϞ āĻā§°ā§
- Air in balloon - air also has mass. āĻŦā§āϞā§āύāϤ āĻĨāĻāĻž āĻŦāĻžāϝāĻŧā§ - āĻŦāĻžāϝāĻŧā§ā§°ā§ āĻā§° āĻĨāĻžāĻā§
Conclusion / āϏāĻŋāĻĻā§āϧāĻžāύā§āϤ: Solid, liquid, and gas - all are matter. āĻāĻ āĻŋāύ āĻŦāĻž āĻā§āĻāĻž, āĻĻā§ā§°ā§ą āĻā§°ā§ āĻā§āĻ - āϏāĻāϞ⧠āĻĒāĻĻāĻžā§°ā§āĻĨāĨ¤
Characteristics of Matter :: āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻŦā§āĻļāĻŋāώā§āĻā§āϝāϏāĻŽā§āĻš
Matter has some special properties.āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŋāĻā§āĻŽāĻžāύ āĻŦāĻŋāĻļā§āώ āĻā§āĻŖ āĻāĻā§āĨ¤
1. Matter is made up of tiny particles :: āĻĒāĻĻāĻžā§°ā§āĻĨ āϏ⧰⧠āϏ⧰⧠āĻāĻŖāĻžā§°ā§ āĻāĻ āĻŋāϤ : All matter is made of very tiny particles which we cannot see with naked eyes. āϏāĻāϞ⧠āĻĒāĻĻāĻžā§°ā§āĻĨ āĻ āϤāĻŋ āϏ⧰⧠āϏ⧰⧠āĻāĻŖāĻžā§°ā§ āĻāĻ āĻŋāϤ, āϝāĻŋāĻŦā§ā§° āĻāĻžāϞ⧠āĻāĻā§āϤ āĻĻā§āĻāĻž āύāĻžāϝāĻžāϝāĻŧāĨ¤
2. Particles of Matter are Very Small. āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻžāĻŦā§ā§° āĻ āϤāĻŋ āϏ⧰⧠: Particles are extremely small in size (microscopic).āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻžāĻŦā§ā§° āĻ āϤāĻŋ āϏ⧰⧠(āĻ āĻŖā§āĻŦā§āĻā§āώāĻŖāĻŋāĻ) āĻāĻāĻžā§°ā§°āĨ¤
3. Particles of Matter are in Constant Motion.āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻžāĻŦā§ā§° āϏāĻĻāĻžāϝāĻŧ āĻāϤāĻŋ āĻā§°āĻŋ āĻĨāĻžāĻā§ : Particles are always moving. This motion increases on heating.āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻžāĻŦā§ā§° āϏāĻĻāĻžāϝāĻŧ āĻāϞāĻŽāĻžāύ āĻ ā§ąāϏā§āĻĨāĻžāϤ āĻĨāĻžāĻā§āĨ¤ āĻā§°āĻŽ āĻĻāĻŋāϞ⧠āĻāϤāĻŋ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϝāĻŧāĨ¤
4. Particles of Matter Attract Each Other. āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻāĻŖāĻžāĻŦā§ā§°ā§ āĻĒā§°āϏā§āĻĒā§°āĻ āĻāĻā§°ā§āώāĻŖ āĻā§°ā§ : There is a force of attraction between particles which holds them together. āĻāĻŖāĻžāĻŦā§ā§°ā§° āĻŽāĻžāĻāϤ āĻāĻā§°ā§āώāĻŖ āĻļāĻā§āϤāĻŋ āĻĨāĻžāĻā§, āϝāĻŋāϝāĻŧā§ āϏāĻŋāĻšāĻāϤāĻ āĻāĻā§āϞāĻā§ āϧ⧰āĻŋ ā§°āĻžāĻā§āĨ¤
Microscopic Concepts :: āĻ āĻŖā§āĻŦā§āĻā§āώāĻŖāĻŋāĻ āϧāĻžā§°āĻŖāĻž
- Microscopic particles: Cannot be seen by naked eyes. āĻ āĻŖā§āĻŦā§āĻā§āώāĻŖāĻŋāĻ āĻāĻŖāĻž: āĻāĻžāϞ⧠āĻāĻā§āϤ āĻĻā§āĻāĻž āύāĻžāϝāĻžāϝāĻŧ
- Particles moving: Shows kinetic energy. āĻāĻŖāĻžā§° āĻāϤāĻŋ: āĻāϤāĻŋāĻļāĻā§āϤāĻŋ āĻŦā§āĻāĻžāϝāĻŧ
- Force of attraction: Keeps matter together. āĻāĻā§°ā§āώāĻŖ āĻļāĻā§āϤāĻŋ: āĻĒāĻĻāĻžā§°ā§āĻĨ āĻāĻā§āϞāĻā§ ā§°āĻžāĻā§
States of Matter :: āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻ ā§ąāϏā§āĻĨāĻžāϏāĻŽā§āĻš :-
Matter exists in three states.āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŽā§āϞāϤāĻ āϤāĻŋāύāĻŋāĻāĻž āĻ ā§ąāϏā§āĻĨāĻžāϤ āĻĒā§ā§ąāĻž āϝāĻžāϝāĻŧāĨ¤
Solid : āĻāĻ āĻŋāύ āĻŦāĻž āĻā§āĻāĻž Fixed shape : āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§°, Fixed volume : āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāϝāĻŧāϤāύ
Ex: Stone, Ice, āĻāĻĻāĻžāĻšā§°āĻŖ: āĻĒāĻžāĻĨā§°, āĻŦā§°āĻĢ
Liquid (āĻĻā§ā§°ā§ą): 1. No fixed shape - āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āύāĻžāĻ 2. Fixed volume - āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāϝāĻŧāϤāύ āĻāĻā§
Ex: Water, Milk, āĻāĻĻāĻžāĻšā§°āĻŖ: āĻĒāĻžāύā§, āĻĻā§āϧ
Gas (āĻā§āĻ) : No fixed shape : āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āύāĻžāĻ, No fixed volume : āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāϝāĻŧāϤāύ āύāĻžāĻ
Ex: Air, Oxygen, āĻāĻĻāĻžāĻšā§°āĻŖ: āĻŦāĻžāϝāĻŧā§, āĻ āĻā§āϏāĻŋāĻā§āύ
Exam Tips : āĻĒā§°ā§āĻā§āώāĻžā§° āĻŦāĻžāĻŦā§ āĻāĻāĻļāĻžā§°ā§ āϏāĻžā§°āĻžāĻāĻļ
- Matter has mass, occupies space, and exists as solid, liquid, and gas.
- āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻā§° āĻāĻā§, āϏā§āĻĨāĻžāύ āĻĻāĻāϞ āĻā§°ā§ āĻā§°ā§ āĻāĻ āĻŋāύ āĻŦāĻž āĻā§āĻāĻž, āĻĻā§ā§°ā§ą, āĻā§āĻ ā§°ā§āĻĒā§ āĻĒā§ā§ąāĻž āϝāĻžāϝāĻŧāĨ¤
What is Matter ? :: āĻĒāĻĻāĻžā§°ā§āĻĨ āĻāĻŋ ? : Click Here
Questions & Answers - āĻĒā§ā§°āĻļā§āύ āĻā§°ā§ āĻāϤā§āϤ⧰
1) Define matter. Give two examples.āĻĒāĻĻāĻžā§°ā§āĻĨā§° āϏāĻāĻā§āĻāĻž āĻĻāĻŋāϝāĻŧāĻžāĨ¤ āĻĻā§āĻāĻāĻž āĻāĻĻāĻžāĻšā§°āĻŖ āĻĻāĻŋāϝāĻŧāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰: Matter is anything that has mass and occupies space. Examples: Ice cube, Wooden block. āϝāĻŋ āĻŦāϏā§āϤā§ā§° āĻā§° āĻĨāĻžāĻā§ āĻā§°ā§ āϏā§āĻĨāĻžāύ āĻĻāĻāϞ āĻā§°ā§ āϤāĻžāĻ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻŦā§āϞāĻž āĻšāϝāĻŧāĨ¤ āĻāĻĻāĻžāĻšā§°āĻŖ: āĻŦā§°āĻĢā§° āĻā§āĻā§ā§°āĻž, āĻāĻžāĻ ā§° āĻā§āĻā§ā§°āĻžāĨ¤
2) What are the three states of matter? Give one example of each. āĻĒāĻĻāĻžā§°ā§āĻĨā§° āϤāĻŋāύāĻŋāĻāĻž āĻ ā§ąāϏā§āĻĨāĻž āĻāĻŋ? āĻĒā§ā§°āϤāĻŋāĻā§ā§° āĻāĻĻāĻžāĻšā§°āĻŖ āĻĻāĻŋāϝāĻŧāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰: Solid - Stone, Liquid - Water, Gas - Air. āĻ ā§āϏ - āĻĒāĻžāĻĨā§°, āĻĻā§ā§°ā§ą - āĻĒāĻžāύā§, āĻā§āĻ - āĻŦāĻžāϝāĻŧā§
3) List three characteristics of matter. āĻĒāĻĻāĻžā§°ā§āĻĨā§° āϤāĻŋāύāĻŋāĻāĻž āĻŦā§āĻļāĻŋāώā§āĻā§āϝ āϞāĻŋāĻāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰:
- Matter is made of tiny particles. āĻĒāĻĻāĻžā§°ā§āĻĨ āϏ⧰⧠āϏ⧰⧠āĻāĻŖāĻžā§°ā§ āĻāĻ āĻŋāϤāĨ¤
- Particles are in constant motion. āĻāĻŖāĻžāĻŦā§ā§° āϏāĻĻāĻžāϝāĻŧ āĻāϞāĻžāĻāϞ āĻā§°āĻŋ āĻĨāĻžāĻā§āĨ¤
- Particles attract each other. āĻāĻŖāĻžāĻŦā§ā§° āĻĒā§°āϏā§āĻĒā§°ā§° āĻĒā§°āĻž āĻāĻā§°ā§āώāĻŖ āĻ āύā§āĻā§ą āĻā§°ā§āĨ¤
4) Why is air considered matter ? āĻŦāĻžāϝāĻŧā§āĻ āĻĒāĻĻāĻžā§°ā§āĻĨ āĻāĻŋāϝāĻŧ āϧ⧰āĻž āĻšāϝāĻŧ ?
Ans / āĻāϤā§āϤ⧰: Air has mass and occupies space. āĻŦāĻžāϝāĻŧā§ā§° āĻā§° āĻāĻā§ āĻā§°ā§ āĻ āϏā§āĻĨāĻžāύ āĻĻāĻāϞ āĻā§°ā§āĨ¤
5) What happens to the motion of particles when matter is heated ? āĻĒāĻĻāĻžā§°ā§āĻĨ āĻā§°āĻŽ āĻā§°āĻŋāϞ⧠āĻāĻŖāĻžā§° āĻāϤāĻŋāϤ āĻāĻŋ āĻšāϝāĻŧ ?
Ans / āĻāϤā§āϤ⧰: The particles move faster when heated. āĻā§°āĻŽ āĻĻāĻŋāϞ⧠āĻāĻŖāĻžāĻŦā§ā§° āĻŦā§āĻāĻŋ āĻĻā§ā§°ā§āϤ āĻāϤāĻŋāϤ āĻāϤāĻŋ āĻā§°ā§āĨ¤
6) Distinguish between solid, liquid, and gas. āĻāĻ āĻŋāύ, āĻĻā§ā§°ā§ą āĻā§°ā§ āĻā§āĻā§° āĻŽāĻžāĻāϤ āĻĒāĻžā§°ā§āĻĨāĻā§āϝ āĻĻāĻŋāϝāĻŧāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰:
- Solid: Fixed shape and volume. Example: Stone / Ice āĻāĻ āĻŋāύ: āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āĻā§°ā§ āĻāϝāĻŧāϤāύāĨ¤ āĻāĻĻāĻžāĻšā§°āĻŖ: āĻĒāĻžāĻĨā§° / āĻŦā§°āĻĢ
- Liquid: No fixed shape but fixed volume. Example: Water / Milk āĻĻā§ā§°ā§ą: āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āύāĻžāĻĨāĻžāĻā§, āĻāĻŋāύā§āϤ⧠āĻāϝāĻŧāϤāύ āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻāĨ¤ āĻāĻĻāĻžāĻšā§°āĻŖ: āĻĒāĻžāύ⧠/ āĻĻā§āϧ
- Gas: No fixed shape or volume. Example: Air / Oxygen āĻā§āĻ: āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āĻā§°ā§ āĻāϝāĻŧāϤāύ āύāĻžāĻĨāĻžāĻā§āĨ¤ āĻāĻĻāĻžāĻšā§°āĻŖ: āĻŦāĻžāϝāĻŧā§ / āĻ āĻā§āϏāĻŋāĻā§āύ
7) What is meant by the attraction force between particles ? Give an example. āĻāĻŖāĻžā§° āĻŽāĻžāĻāϤ āĻāĻā§°ā§āώāĻŖ āĻļāĻā§āϤāĻŋ āĻŽāĻžāύ⧠āĻāĻŋ? āĻāĻĻāĻžāĻšā§°āĻŖ āĻĻāĻŋāϝāĻŧāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰: Attraction force is the force that holds particles together. Example: Water droplets forming. āĻāĻā§°ā§āώāĻŖ āĻļāĻā§āϤāĻŋ āĻŽāĻžāύ⧠āĻāĻŖāĻžāĻŦā§ā§° āĻāĻā§āϞāĻā§ ā§°āĻžāĻāĻŋāĻŦāϞ⧠āĻĨāĻāĻž āĻļāĻā§āϤāĻŋāĨ¤ āĻāĻĻāĻžāĻšā§°āĻŖ: āĻĒāĻžāύā§ā§° āĻĢā§āĻāĻāĻž āĻŽāĻŋāϞāĻŋ āϝā§ā§ąāĻžāĨ¤
What is Matter ? :: āĻĒāĻĻāĻžā§°ā§āĻĨ āĻāĻŋ ? : Click Here
8) Explain why ice has a fixed shape but water does not. āĻŦā§āĻā§ā§ąāĻž āĻāĻŋāϝāĻŧ āĻŦā§°āĻĢā§° āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āĻĨāĻžāĻā§ āĻāĻŋāύā§āϤ⧠āĻĒāĻžāύā§ā§° āύāĻžāĻāĨ¤
Ans / āĻāϤā§āϤ⧰: In ice, particles are tightly packed - fixed shape. In water, particles can move - no fixed shape. āĻŦā§°āĻĢāϤ āĻāĻŖāĻžāĻŦā§ā§° āĻļāĻā§āϤāĻāĻžāĻŦā§ āĻŽāĻŋāϞāĻŋ āĻāĻā§ - āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§°āĨ¤ āĻĒāĻžāύā§āϤ āĻāĻŖāĻžāĻŦā§ā§° āĻāϞāĻŋāĻŦ āĻĒāĻžā§°ā§ - āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āĻāĻāĻžā§° āύāĻžāĻāĨ¤
9) Draw a labeled diagram showing the three states of matter.āĻĒāĻĻāĻžā§°ā§āĻĨā§° āϤāĻŋāύāĻŋāĻāĻž āĻ ā§ąāϏā§āĻĨāĻžā§° āϞā§āĻŦā§āϞāϏāĻš āĻāĻŦāĻŋ āĻāĻāĻāĻžāĨ¤
Ans / āĻāϤā§āϤ⧰: Solid - Ice / Stone , Liquid - Water / Milk , Gas - Air / Oxygen
10) Classify the following as solid, liquid, or gas: Sugar, Milk, Oxygen. āĻāĻāĻŦā§ā§°āĻ āĻāĻ āĻŋāύ, āĻĻā§ā§°ā§ą āĻŦāĻž āĻā§āĻāϤ āĻāĻžāĻ āĻā§°āĻž: āĻā§āύā§, āĻĻā§āϧ, āĻ āĻā§āϏāĻŋāĻā§āύ
Ans / āĻāϤā§āϤ⧰: 1. Sugar - Solid / āĻā§āύ⧠- āĻā§āĻāĻž , 2. Milk - Liquid / āĻĻā§āϧ - āĻĻā§ā§°ā§ą , 3. Oxygen - Gas / āĻ āĻā§āϏāĻŋāĻā§āύ - āĻā§āĻ
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1. āϤāϞāϤ āĻĻāĻŋā§āĻž āĻāώā§āĻŖāϤāĻžāĻŦā§ā§° āĻā§āϞāĻāĻŋā§āĻžāĻ āϏā§āĻā§āϞāϤ āĻĒā§ā§°āĻāĻžāĻļ āĻā§°āĻžāĨ¤ (Convert the following temperatures into Celsius scale.)
āϏā§āϤā§āϰ / Formula: °C = K − 273
(a) 300 K
āĻāϤā§āϤ⧰ / Ans: 300 − 273 = 27°C, 300 K = 27°C
(b) 573 K
āĻāϤā§āϤ⧰ / Ans: 573 − 273 = 300°C, 573 K = 300°C
2. āϤāϞ⧰ āĻāώā§āĻŖāϤāĻžāĻŦāĻŋāϞāĻžāĻāϤ āĻĒāĻžāύā§ā§° āĻā§āϤāĻŋāĻ āĻ ā§ąāϏā§āĻĨāĻž āĻāĻŋ āĻšāĻŦ ? (What will be the physical state of water at the following temperatures ?)
(a) 250°C
āĻāϤā§āϤ⧰ / Ans: 250°C āϤ āĻĒāĻžāύ⧠āĻā§āĻā§ā§ āĻ ā§ąāϏā§āĻĨāĻžāϤ āĻĨāĻžāĻāĻŋāĻŦāĨ¤ (At 250°C, water will be in gaseous state.)
(b) 100°C
āĻāϤā§āϤ⧰ / Ans: 100°C āϤ āĻĒāĻžāύ⧠āĻāϤāϞāύ āĻ ā§ąāϏā§āĻĨāĻžāϤ āĻĨāĻžāĻāĻŋāĻŦ āĻā§°ā§ āĻā§āϞā§ā§āĻž āĻā§°ā§ āĻā§āĻā§ā§ āĻĻā§ā§ā§ āĻ ā§ąāϏā§āĻĨāĻž āĻĨāĻžāĻāĻŋāĻŦ āĻĒāĻžā§°ā§āĨ¤ (At 100°C, water will be at boiling point and both liquid and gaseous states may exist.)
3. āĻā§āύ⧠āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻā§āϤāĻŋāĻ āĻ ā§ąāϏā§āĻĨāĻžā§° āĻĒā§°āĻŋāĻŦā§°ā§āϤāύ⧰ āϏāĻŽā§āĻā§ā§ąāĻžāϤ āĻāώā§āĻŖāϤāĻž āϏā§āĻĨāĻŋā§° āĻšā§ āĻĨāĻžāĻā§ āĻāĻŋā§ ? (Why does temperature remain constant during the change of state of a substance ?)
āĻāϤā§āϤ⧰ / Ans: āĻ ā§ąāϏā§āĻĨāĻžā§° āĻĒā§°āĻŋāĻŦā§°ā§āϤāύ⧰ āϏāĻŽā§āϤ āĻĒā§ā§°ā§ā§āĻ āĻā§°āĻž āϤāĻžāĻĒ āĻāĻŖāĻŋāĻāĻžāĻŦā§ā§°ā§° āĻŽāĻžāĻā§° āĻāĻāϰā§āώāĻŖ āĻŦāϞ āĻāĻžāĻāĻŋāĻŦāϞ⧠āĻŦā§āĻ¯ā§ąāĻšā§āϤ āĻšā§āĨ¤ āϏā§āĻāĻāĻžā§°āĻŖā§ āĻāώā§āĻŖāϤāĻž āϏā§āĻĨāĻŋā§° āĻĨāĻžāĻā§āĨ¤ (During change of state, the supplied heat is used to overcome the force of attraction between particles. Therefore, the temperature remains constant.)
4. āĻŦāĻžāϝāĻŧā§āĻŽāĻŖā§āĻĄāϞā§ā§ āĻā§āĻ āĻā§āϞā§ā§āĻž āĻā§°āĻŋāĻŦ āĻĒā§°āĻž āĻĒāĻĻā§āϧāϤāĻŋ āĻāĻāĻž āĻā§ā§ąāĻžāĨ¤ (Name one method by which atmospheric gases can be liquefied.)
āĻāϤā§āϤ⧰ / Ans: āĻāĻā§āĻ āĻāĻžāĻĒ āĻĒā§āϰā§ā§āĻ āĻā§°āĻŋ āĻā§°ā§ āĻāώā§āĻŖāϤāĻž āĻāĻŽāĻžāĻ āĻŦāĻžāϝāĻŧā§āĻŽāĻŖā§āĻĄāϞā§ā§ āĻā§āĻ āĻā§āϞā§ā§āĻž āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋāĨ¤ (Atmospheric gases can be liquefied by applying high pressure and lowering temperature.)
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Evaporation (āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ) : Clisk Here
Definition: Evaporation is the process by which a liquid changes into vapour from its surface at any temperature below its boiling point. āϏāĻāĻā§āĻāĻž: āĻā§āϞā§ā§āĻž āĻĒāĻĻāĻžā§°ā§āĻĨā§° āĻĒā§āώā§āĻ ā§° āĻĒā§°āĻž āĻāϤāϞāĻžāĻāĻā§° āϤāϞ⧰ āϝāĻŋāĻā§āύ⧠āĻāώā§āĻŖāϤāĻžāϤ āĻā§āĻā§ā§ āĻ ā§ąāϏā§āĻĨāĻžāϞ⧠āĻĒā§°āĻŋāĻŦāϰā§āϤāĻŋāϤ āĻšā§ā§ąāĻžāĻ āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ āĻŦā§āϞā§āĨ¤
1. Desert cooler āĻāĻāĻžāĻ āĻļā§āώā§āĻ āĻā§°āĻŽ āĻĻāĻŋāύāϤ āĻāĻžāϞāĻā§ āĻ āĻžāĻŖā§āĻĄāĻž āĻā§°ā§ āĻāĻŋā§ ? (Why does a desert cooler cool better on a hot dry day ?)
āĻāϤā§āϤ⧰ / Ans: āĻļā§āώā§āĻ āĻā§°āĻŽ āĻĻāĻŋāύāϤ āĻŦāĻžāϝāĻŧā§āϤ āĻāϰā§āĻĻā§āϰāϤāĻž āĻāĻŽ āĻĨāĻžāĻā§āĨ¤ āϏā§ā§ā§ āĻĒāĻžāύ⧠āĻĻā§āϰā§āϤ āĻŦāĻžāώā§āĻĒā§āĻā§āϤ āĻšā§āĨ¤ āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ⧰ āϏāĻŽā§āϤ āĻĒāĻžāύā§ā§ā§ āĻāĻžā§°āĻŋāĻāĻĢāĻžāϞ⧰ āĻĒā§°āĻž āĻ āϧāĻŋāĻ āϤāĻžāĻĒ āĻļā§āώāĻŖ āĻā§°ā§āĨ¤ āĻĢāϞāϤ desert cooler āĻ āĻŦā§āĻāĻŋ āĻ āĻžāĻŖā§āĻĄāĻž āĻā§°ā§āĨ¤ On a hot dry day, humidity in the air is low. So water evaporates faster. During evaporation, water absorbs more heat from the surroundings. Therefore, the desert cooler cools better.
2. āĻā§āϰā§āώā§āĻŽāĻāĻžāϞāϤ āĻŽāĻžāĻāĻŋā§° āĻāϞāĻšā§° āĻĒāĻžāύ⧠āĻ āĻžāĻŖā§āĻĄāĻž āĻšā§ āĻĨāĻžāĻā§ āĻāĻŋā§ ? (Why does water remain cool in an earthen pot during summer ?)
āĻāϤā§āϤ⧰ / Ans: āĻŽāĻžāĻāĻŋā§° āĻāϞāĻšāϤ āϏ⧰⧠āϏ⧰⧠⧰āύā§āϧā§ā§° āĻĨāĻžāĻā§āĨ¤ āĻāĻ ā§°āύā§āϧā§ā§°ā§° āĻŽāĻžāĻā§ā§°ā§ āĻĒāĻžāύ⧠āĻŦāĻžāĻšāĻŋā§°āϞ⧠āĻāĻšāĻŋ āĻŦāĻžāώā§āĻĒā§āĻā§āϤ āĻšā§āĨ¤ āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ⧰ āϏāĻŽā§āϤ āϤāĻžāĻĒ āĻļā§āώāĻŖ āĻā§°āĻžā§° āĻŦāĻžāĻŦā§ āĻĒāĻžāύ⧠āĻ āĻžāĻŖā§āĻĄāĻž āĻšā§ āĻĨāĻžāĻā§āĨ¤ An earthen pot has tiny pores. Water comes out through these pores and evaporates. During evaporation, heat is absorbed, so the water remains cool.
3. āĻšāĻžāϤ⧰ āϤāϞā§ā§ąāĻžāϤ āĻāĻāĻŋāĻāύ, āĻĒā§āĻā§āϰāϞ āĻŦāĻž āϏā§āĻāύā§āϧāĻŋ āĻāϤ⧰ āĻĸāĻžāϞāĻŋ āϞ'āϞ⧠āĻ āĻžāĻŖā§āĻĄāĻž āĻ āύā§āĻā§ą āĻšā§ āĻāĻŋā§ ? Why do we feel cool when acetone, petrol, or perfume is poured on the palm ?
āĻāϤā§āϤ⧰ / Ans: āĻāĻāĻŋāĻāύ, āĻĒā§āĻā§āϰāϞ āĻā§°ā§ āĻāϤ⧰ āĻĻā§āϰā§āϤ āĻŦāĻžāώā§āĻĒā§āĻā§āϤ āĻšā§āĨ¤ āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ⧰ āϏāĻŽā§āϤ āĻāĻšāĻāϤ⧠āĻšāĻžāϤ⧰ āϤāϞā§ā§ąāĻžā§° āĻĒā§°āĻž āϤāĻžāĻĒ āĻļā§āώāĻŖ āĻā§°ā§āĨ¤ āϏā§ā§ā§ āĻ āĻžāĻŖā§āĻĄāĻž āĻ āύā§āĻā§ą āĻšā§āĨ¤ Acetone, petrol, and perfume evaporate quickly. During evaporation, they absorb heat from the palm. Therefore, we feel cool.
4. āĻā§°āĻŽ āĻāĻžāĻš āĻŦāĻž āĻāĻžāĻā§ā§° āĻāĻžāĻĒāϤ āϞ⧠āĻā§ā§ąāĻžāϤāĻā§ āĻĒā§āϞā§āĻāϤ āϞ⧠āĻā§ā§ąāĻž āϏāĻšāĻ āĻāĻŋā§ ? Why is it easier to drink hot tea or milk from a plate than from a cup ?
āĻāϤā§āϤ⧰ / Answer: āĻĒā§āϞā§āĻāϤ āĻāĻžāĻš āĻŦāĻž āĻāĻžāĻā§ā§°ā§° āĻĒā§āώā§āĻ āĻāĻžāϞāĻŋ āĻŦā§āĻāĻŋ āĻšā§āĨ¤ āϏā§ā§ā§ āĻŦāĻžāώā§āĻĒā§āĻāĻŦāύ āĻĻā§āϰā§āϤ āĻšā§ āĻā§°ā§ āϤāĻžāĻĒ āϏā§āύāĻāĻžāϞ⧠āĻāĻŽā§āĨ¤ āϏā§āĻāĻāĻžā§°āĻŖā§ āĻĒā§āϞā§āĻāϤ āϞ⧠āĻā§ā§ąāĻž āϏāĻšāĻāĨ¤ In a plate, tea or milk has a larger surface area. So evaporation becomes faster and the temperature decreases quickly. Therefore, it is easier to drink from a plate.
5. āĻā§āϰā§āώā§āĻŽāĻāĻžāϞāϤ āĻāĻŽāĻŋ āĻāĻŋ āϧ⧰āĻŖā§° āĻāĻžāĻĒā§ā§° āĻĒāĻŋāύā§āϧāĻŋāĻŦ āϞāĻžāĻā§ ? What type of clothes should we wear in summer ?
āĻāϤā§āϤ⧰ / Ans: āĻā§āϰā§āώā§āĻŽāĻāĻžāϞāϤ āĻĒāĻžāϤāϞ āĻā§°ā§ āĻāĻĒāĻžāĻšā§ āĻāĻžāĻĒā§ā§° āĻĒāĻŋāύā§āϧāĻŋāĻŦ āϞāĻžāĻā§āĨ¤ āĻāĻĒāĻžāĻšā§ āĻāĻžāĻĒā§ā§°ā§ āĻāĻžāĻŽ āĻļā§āώāĻŖ āĻā§°āĻŋ āϏāĻšāĻā§ āĻŦāĻžāώā§āĻĒā§āĻā§āϤ āĻšā§ā§ąāĻžāϤ āϏāĻšāĻžā§ āĻā§°ā§ āĻā§°ā§ āĻĻā§āĻš āĻ āĻžāĻŖā§āĻĄāĻž ā§°āĻžāĻā§āĨ¤ In summer, we should wear light cotton clothes. Cotton absorbs sweat and helps it evaporate easily, keeping the body cool.