MATTER IN OUR SURROUNDINGS
What is matter? Matter is anything that has mass and takes up space. At a minimum, matter requires at least one subatomic particle, although most matter consists of atoms. Egs: The air we breathe, the stones, food clothes, furniture etc. MATTER HAS MASS AND OCCUPIES VOLUME
Physical properties of matter 1. Matter is made up of particles Activity: 1 Dissolving sugar/salt in water. Aim: To understand matter has particles
2. The particles of matter are infinitely small Activity: 2 Take 2-3 crystals of potassium permanganate and dissolve them in 100 mL of water. . Take out 10 mL of this solution and put it into another 90 mL of clear water. e Keep diluting the solution like this 5 to 8 times. . Is the water still coloured? Yes! AIM: To verify particles of matter are very small.
3. Particles of matter have space between them In the previous 2 activities the reason why the salt or sugar was dissolved in water is the Presence of space in between its particles. The extent of intermolecularspace varies from one state of matter to other. Gas Liquid Solid
4. Particles of matter are continuously moving. Particles of matter possess kinetic energy which is responsible for their continuous motion. Kinetic energy is the energy that any body possesses due to the virtue of its motion. This kinetic energy increases as the temperature rises, which in turn increases the speed of movement of particles. Activity: 3 . Put an unlitincense stick in a corner of your class. How close do you have to go near it so as to get its smell? e Now light the incense stick. What happens? Do you get the smell sitting at a distance?
Diffusion The intermixing of particles of two different types of matter on their own is called diffusion. We also observe that on heating, diffusion becomes faster as with rise in temperature the kinetic energy increases. The term "diffusion" comes from the Latin word diffundere, which means "to spread out".
5. Particles of matter attract each other . Take an iron nail, a piece of chalk and a rubber band. . Try breaking them by hammering, cutting or stretching. In which of the above three substances do you think the particles are held together with greater force? Particles of matter have forces of attraction acting between them. This force of attraction has different strength in different states of matter. How closely bound the particles are depends on the force of attraction.