Matter in Our Surroundings Topic 1

Matter

  • Any thing which occupies space is called Matter
  • The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand – every thing is matter
  • Early Indian philosophers classified matter in the form of five basic elements – the “Panch Tatva”– air, earth, fire, sky and water.
  • According to them everything, living or nonliving, was made up of these five basic elements.
  • Modern day scientists have evolved two types of classification of matter based on their physical properties and chemical nature.
  • On The basis of physical properties matter are Solid ,Liquid and gases
  • On The basis of chemical properties matter are Elements, compound and Mixtures

This Chapter will deal only with Classification Based on Physical Properties.

Physical Nature of Matter

 

MATTER IS MADE UP OF PARTICLES

  • Everything around us is made of tiny pieces or particles
  • our chair is made of particles, our table is made of particles and this phone or tab you are holding is also made of particles
  • The number of particles in everything is, however, very, very large. For example, a small rain drop (water drop) contains about 1021 particles of water in it !
  • The particles which make up matter are so small that we cannot see them even with a high power microscope.
  • Even without seeing them, we have certain evidence which tells us that all the things (or all the matter) is made of tiny particles.
  • It also shows that matter are constantly ‘moving’ (they are in motion)
Rain drop on a leaf has 1000000000000 particles

Proof to show that There are particles in matter

 

Dissolving a Solid in a Liquid

  • Potassium permanganate is a purple colored solid substance and water is a colorless liquid,
  • we dissolve potassium permanganate in water
  • When a crystal of potassium permanganate is placed in a beaker of water, the water slowly turns purple on its own, even without stirring
  • Both, potassium. permanganate crystal and water are made up of tiny particles.
  • The particles of potassium permanganate are purple coloured whereas the particles of water are colourless.
  • When the potassium permanganate crystal is put in water, its particles separate from one another.
  • Purple color particle of potassium permanganate spread throughout water making the whole water look purple
  • The particles of potassium permanganate get into the spaces between the particle of the water.

Activity -2

  • Take salt or sugar and drop few sppon of either in water
  • When we dissolve salt in water, the particles of salt get into the spaces between particles of water.
  • The zig-zag movement of the small particles suspended in a liquid or gas is called Brownian motion-Brownian motion increases on increasing temperature.

The existence of Brownian motion gives us two conclusions about the nature of matter :
(i) that matter is made up of tiny particles, and
(ii) that the particles of matter are constantly moving.

Characteristics of Particles of Matter

  • The particles of matter are very, very small
  • The particles of matter have spaces between them
  • The particles of matter are constantly moving
  • The particles of matter attract each other
  1. The particles of matter are very, very small

Activity

Estimating how small are the particles of matter. With every dilution, though the colour becomes light, it is still visible.
  • Take potassium permanganate and water.
  • Potassium permanganate is a kind of matter.
  • We take 2 or 3 small crystals of potassium permanganate and dissolve it in 100 millilitres (100 mL) of water in a beaker.
  • We will get a deep purple coloured solution of potassium permanganate in water
  • Take 10 mL of deep purple solution of potassium permanganate from the first beaker and mix it with 90 mL of water present in second beaker, to dilute it
  • Due to this dilution, the colour of potassium permanganate solution in the second beaker becomes a bit lighter.
  • Now, take 10 mL of potassium permanganate solution from the second beaker and mix it with 90 mL of water present in the third beaker, to dilute it further
  • The colour of solution will become still lighter.
  • We keep on diluting the potassium permanganate .solution like this a number of times (say, five times).
  • In this way, we get a very dilute solution of potassium permanganate in water but the water is still coloured (it has a light pink colour now)
  • This experiment shows that just 2 or 3 tiny crystals of potassium permanganate can impart colour to a large volume of water.
  • From this observation we conclude that each potassium permanganate crystal

PARTICLES OF MATTER HAVE SPACE BETWEEN THEM

  • when You add salt or sugar or Dettol or  potassium permanganate to water
  • The particles of sugar, salt, Dettol, or potassium permanganate got evenly distributed in water.
  • Similarly, when we make tea, coffee or lemonade (nimbu paani ), particles of one type of matter get into the spaces between particles of the other.
  • This shows that there is enough space between particles of matter.

PARTICLES OF MATTER ARE CONTINUOUSLY MOVING

  • Put an unlit incense stick in a corner of your study room.
  • You have to go very closer to smell it
  • Now light the incense stick.
  • You can get the smell of the incense stick even if you are at a distance

Activity-4

  • Drop a crystal of copper sulphate or potassium permanganate into a glass of hot water and another containing cold water.
  • Do not stir the solution.
  • We can observe the rate of mixing is higher with hot water
  • Particles of matter are continuously moving, that is, they possess what we call the kinetic energy.
  • As the temperature rises,particles move faster.
  • So, we can say that with increase in temperature the kinetic energy of the particles also increases.

PARTICLES OF MATTER ATTRACT EACH OTHER

  • The particles of matter have force acting between them.
  • Take an iron nail, a piece of chalk and a cube of ice
  • Break it with a hammer
  • You can Observe its very easy to break the chalk particles than ice cube. and it is hard to break the nail
  • This force keeps the particles together.
  • The strength of this force of attraction varies from one kind of matter to another.
  • Open a water tap, try breaking the stream of water with your fingers.
  • Also try moving your hand through a stone
  • You will find you can break the stream of water but not through the stream
  • This shows the Particle of water has less attractive force than stone

Solve few questions Here before Moving ahead 

  1. Which of the following are matter?
    Chair, air, love, smell, hate, almonds, thought, cold, colddrink, smell of perfume.
  2. Give reasons for the following observation:
    The smell of hot sizzling food reaches you several metres away, but to get the smell from
    cold food you have to go close.
  3.  A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
  4.  What are the characteristics of the particles of matter?

Visit Here to download NCERT Solutions For Class 9th Science on Matter of Surrounding

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