MATTER IN OUR SURROUNDINGS

Matter hamare surrounding mein har cheez hai jo space occupy karti hai aur jiska mass hota hai.

Matter ka Classification:

• Ancient Indian Philosophers: Matter ko 'Panch Tatva' (air, earth, fire, sky, water) mein classify karte the.
• Modern Scientists: Matter ko do bases par classify karte hain:
• Physical Properties: Is chapter mein hum is par focus karenge.
• Chemical Nature: Isko hum next chapters mein padhenge.

Key Concepts:

• Matter is made up of particles:
• Pehle do schools of thought the: ek kehta tha matter continuous hai (like wood block), doosra kehta tha matter particles se bana hai (like sand).
• Activity 1.1 (Salt in Water): Jab hum salt ko water mein dissolve karte hain, toh salt particles water particles ke beech ke spaces mein adjust ho jaate hain. Water level change nahi hota. Ye show karta hai ki matter particles se bana hai aur unke beech space hota hai.
• [IMAGE: TODO: Salt dissolving in water - magnified view]
• How small are these particles?
• Activity 1.2 (Potassium Permanganate Dilution): Potassium permanganate ke kuch crystals bhi large volume of water ko colour kar sakte hain.
• Iska matlab hai ki ek crystal mein millions of tiny particles hote hain jo repeatedly divide hokar chhote-chhote particles banate rehte hain.
• Ye particles itne chhote hote hain ki hum imagine bhi nahi kar sakte (beyond our imagination).
• [IMAGE: TODO: Dilution of potassium permanganate]

Matter ke particles ki teen main characteristics hoti hain:

1. Particles of Matter Have Space Between Them:

• Observation: Activities 1.1 (salt in water), 1.2 (potassium permanganate dilution), tea/coffee/lemonade banana, sab mein particles ek doosre ke spaces mein adjust ho jaate hain.
• Conclusion: Iska matlab hai ki matter ke particles ke beech empty spaces (interparticle spaces) hote hain.

2. Particles of Matter Are Continuously Moving:

• Kinetic Energy: Particles continuously move karte rehte hain, iska matlab hai ki unke paas kinetic energy hoti hai.
• Temperature ka Effect:
• Temperature badhane par particles ki speed badhti hai.
• So, temperature increase hone par kinetic energy bhi increase hoti hai.
• Diffusion:
• Definition: Do different types ke matter ke particles ka apne aap intermix hona diffusion kehlata hai.
• Examples: Incense stick ki smell failna (Activity 1.3), ink ka water mein spread hona (Activity 1.4), potassium permanganate ka water mein dissolve hona.
• Temperature ka Effect on Diffusion: Heating par diffusion faster ho jaata hai, kyunki particles ki kinetic energy badh jaati hai.
• Activity 1.5 (Hot vs. Cold Water): Hot water mein diffusion faster hota hai cold water ke comparison mein.

3. Particles of Matter Attract Each Other:

• Interparticle Force: Matter ke particles ke beech force of attraction hota hai jo unhe ek saath hold karta hai.
• Strength of Force: Is force ki strength different types of matter mein different hoti hai.
• Activities:
• Activity 1.6 (Human Chain): Solid (Idu-Mishmi dancers) mein force strongest, liquid (holding hands) mein moderate, gas (finger tips) mein weakest.
• Activity 1.7 (Iron nail, chalk, rubber band): Iron nail ko break karna sabse difficult hai, matlab uske particles ke beech force strongest hai.
• Activity 1.8 (Cutting water surface): Water ki surface ko cut karna difficult hai, kyunki water particles ke beech attraction force hota hai jo unhe together rakhta hai.

Matter mainly teen states mein exist karta hai: Solid, Liquid, aur Gas. Ye states particles ki arrangement, motion, aur interparticle forces mein differences ki wajah se hoti hain.

1. The Solid State:

• Properties:
• Definite shape aur distinct boundaries hoti hain.
• Fixed volume hota hai.
• Negligible compressibility (compress nahi kar sakte).
• Rigid hote hain (shape change karna difficult).
• Particles closely packed hote hain aur apni fixed positions par vibrate karte hain.
• Interparticle forces of attraction strongest hote hain.
• Diffusion bahut slow ya negligible hota hai.
• Examples: Pen, book, iron almirah, stone, sugar.
• Activity 1.9: Pen, book, needle, wooden stick — sabki definite shape, fixed volume, aur negligible compressibility hoti hai.

2. The Liquid State:

• Properties:
• No definite shape, container ka shape le lete hain.
• Fixed volume hota hai.
• Fluid hote hain (flow kar sakte hain).
• Less rigid than solids.
• Low compressibility (solids se zyada, gases se kam).
• Particles closely packed hote hain but freely move kar sakte hain (slide over each other).
• Interparticle forces of attraction moderate hote hain.
• Diffusion solids se faster hota hai.
• Examples: Water, milk, oil, juice.
• Activity 1.10: Liquids ka volume fixed rehta hai, par shape container ke hisaab se change hoti hai.

3. The Gaseous State:

• Properties:
• No definite shape aur no fixed volume, container ka poora volume occupy kar lete hain.
• Highly compressible hote hain.
• Fluid hote hain.
• Particles bahut loosely packed hote hain aur randomly high speed se move karte hain.
• Interparticle forces of attraction weakest hote hain.
• Diffusion fastest hota hai.
• Examples: Air, LPG, CNG, oxygen.
• Activity 1.11 (Syringe Experiment): Gases ko sabse easily compress kiya ja sakta hai (piston easily push hota hai), liquids ko thoda kam, aur solids ko negligible.
• [IMAGE: TODO: Syringe experiment showing compressibility]

Particle Arrangement Comparison:

• Solids: Particles ordered, fixed positions, vibrate.
• Liquids: Particles less ordered, slide over each other.
• Gases: Particles highly disordered, random, rapid motion.

Matter apni state change kar sakta hai by changing temperature ya pressure.

1. Effect of Change of Temperature:

• Solid to Liquid (Melting/Fusion):
• Solid ko heat karne par particles ki kinetic energy badhti hai.
• Particles faster vibrate karte hain aur attraction forces ko overcome karte hain.
• Ek temperature par solid melt hokar liquid ban jaata hai.
• Melting Point: Woh minimum temperature jis par solid melt hokar liquid banta hai atmospheric pressure par.
• Latent Heat of Fusion: Melting point par, jab solid liquid mein convert hota hai, tab temperature change nahi hota. Ye heat energy particles ke beech ke attraction forces ko overcome karne mein use hoti hai. Is hidden heat ko Latent Heat of Fusion kehte hain (1 kg solid ko liquid mein convert karne ke liye required heat).
• Example: Ice ka water banna (Melting point of ice = 0°C or 273.15 K).
• Liquid to Gas (Boiling/Vaporisation):
• Liquid ko heat karne par particles ki kinetic energy aur badhti hai.
• Particles itni energy gain kar lete hain ki attraction forces ko poori tarah se break kar dete hain aur gas mein convert ho jaate hain.
• Boiling Point: Woh temperature jis par liquid boil hokar gas mein convert hota hai atmospheric pressure par.
• Boiling ek bulk phenomenon hai: Poore liquid ke particles energy gain karke vapour mein convert hote hain.
• Latent Heat of Vaporisation: Boiling point par, jab liquid gas mein convert hota hai, tab temperature change nahi hota. Ye hidden heat energy particles ke beech ke attraction forces ko overcome karne mein use hoti hai. Is hidden heat ko Latent Heat of Vaporisation kehte hain (1 kg liquid ko gas mein convert karne ke liye required heat).
• Example: Water ka steam banna (Boiling point of water = 100°C or 373.15 K).
• Gas to Liquid (Condensation): Gas ko cool karne par particles ki kinetic energy kam hoti hai, attraction forces badhte hain aur gas liquid mein convert ho jaati hai.
• Liquid to Solid (Freezing/Solidification): Liquid ko cool karne par particles ki kinetic energy aur kam hoti hai, attraction forces itne strong ho jaate hain ki particles fixed positions par settle ho jaate hain aur liquid solid mein convert ho jaata hai.
• Sublimation: Direct change of state from solid to gas (ya vice-versa) without passing through liquid state.
• Example: Camphor (kapoor), Naphthalene balls, Ammonium chloride, Dry ice (solid CO₂).
• Deposition: Direct change of state from gas to solid.
• [IMAGE: TODO: Sublimation of camphor experiment]

2. Effect of Change of Pressure:

• Gas ko compress karna: Jab hum gas par pressure apply karte hain, toh particles ek doosre ke close aa jaate hain.
• Cooling ke saath: Pressure increase karne aur temperature decrease karne se gas ko liquid mein convert kiya ja sakta hai (liquefaction of gases).
• Example: Dry ice (solid CO₂) high pressure par gas se directly solid banti hai, aur pressure release karne par directly gas mein convert hoti hai.
• [IMAGE: TODO: Gas compression to liquid]

Interconversion of States of Matter:

• Flowchart:
• Solid $\xrightarrow{\text{Heating / Fusion}}$ Liquid $\xrightarrow{\text{Heating / Vaporisation}}$ Gas
• Gas $\xrightarrow{\text{Cooling / Condensation}}$ Liquid $\xrightarrow{\text{Cooling / Freezing}}$ Solid
• Solid $\xrightarrow{\text{Sublimation}}$ Gas
• Gas $\xrightarrow{\text{Deposition}}$ Solid

Evaporation ek special type ka state change hai jo liquid se gas mein hota hai, lekin boiling point se neeche ke temperature par.

Evaporation kya hai?

• Definition: Liquid ka uske boiling point se neeche kisi bhi temperature par vapours mein change hona evaporation kehlata hai.
• Surface Phenomenon: Evaporation ek surface phenomenon hai. Sirf liquid ki surface par maujood particles jinmein high kinetic energy hoti hai, woh attraction forces ko break karke vapour mein convert hote hain.
• Examples: Geela kapda sukhna, water ka apne aap vapour mein change hona jab uncovered rakha ho.

Evaporation ko Affect Karne Wale Factors:

Evaporation ki rate in factors par depend karti hai:

1. Surface Area:

• Surface area badhne par evaporation ki rate badhti hai.
• Reason: Zyada surface area matlab zyada particles surface par exposed hain jo vapour mein convert ho sakte hain.
• Example: Geela kapda failakar sukhana jaldi sukhta hai.

1. Temperature:

• Temperature badhne par evaporation ki rate badhti hai.
• Reason: High temperature par particles ki kinetic energy badhti hai, aur zyada particles attraction forces ko overcome karke vapour mein convert ho paate hain.
• Example: Garmiyon mein kapde jaldi sukhte hain.

1. Humidity:

• Humidity kam hone par evaporation ki rate badhti hai.
• Reason: Humidity ka matlab hai air mein water vapour ki amount. Agar air mein already zyada water vapour hai, toh liquid se aur water vapour add hone ki capacity kam ho jaati hai.
• Example: Rainy season mein kapde der se sukhte hain kyunki humidity high hoti hai.

1. Wind Speed:

• Wind speed badhne par evaporation ki rate badhti hai.
• Reason: High wind speed water vapour particles ko air se door le jaati hai, jisse surrounding air mein water vapour ki concentration kam ho jaati hai aur evaporation fast hota hai.
• Example: Hawa mein kapde jaldi sukhte hain.

Evaporation se Cooling Kaise Hoti Hai?

• Evaporation ke dauran, liquid ke particles jo vapour mein convert hote hain, woh surroundings se latent heat absorb karte hain.
• Is heat absorption ki wajah se surroundings cool ho jaati hain.
• Examples:
• Humein garmi mein pasina (sweat) aata hai aur jab woh evaporate hota hai toh cooling feel hoti hai.
• Hath par spirit ya petrol dalne par thanda lagta hai.
• Garmi mein log chhat par pani chhidakte hain taaki evaporation se cooling ho.
• Mitti ke ghade (earthen pots) mein pani thanda rehta hai kyunki ghade ke pores se pani evaporate hota rehta hai aur cooling karta hai.
• Cotton clothes garmi mein comfortable hote hain kyunki woh sweat ko easily absorb karte hain aur uske evaporation se cooling hoti hai.