Objective:
Matter in any form has mass, volume and density. The form of matter, in which, the molecules are closely placed so that, it can assume a definite shape are called solids. In liquids, the molecules move freely, but in an ordered way and assume various shapes according to the shape of the container in which it is taken. Gas molecules are in random motion and takes the shape of the container by expanding till it fills the entire volume. Gases are invisible, whereas solids and liquids are visible and can be perceived by touching. There are certain materials like water which exists in all the three forms. In the case of such materials the change of state occurs when heat is supplied.
Materials:
Stone
One glass of water
Inflated Balloon
Activity :
Introduce the terms solids, liquids and gases. Divide students into small groups and provide each group with above materials. Let them examine each of them for some time and instruct them to write down the peculiarity of each of these materials. Instruct them to try to pass their thumbs through stone and water. Open the seal of the balloon and let them repeat the above activity. Pour water in the glass into another tumbler of different shape.
Analysis and conclusion:
From the activity students will understand that it is possible to feel solids and liquids through touching, whereas gases are invisible and its presence can’t be felt through touching. They will also understand that solids have definite shape whereas the other two don’t have any shape.
Objective
Introduce the peculiar arrangement of molecules inside solids, liquids and gases. Let them observe the following activity.
Activity
Take a glass box and arrange small chalk pieces one above another till it fills the entire space. Remove two layers and shake the box so that the ordered arrangement inside the box is disturbed. Now remove two more layers and shake the box so that, the chalk pieces move randomly inside the box.
Analysis and conclusion: From the observations students will understand the arrangement of molecules in three states of matter. They will understand that, the molecules inside the gases are widely spaced.
Objective:
There are materials which occur in different forms under different conditions.
Activity:
Take three glasses of water, place one glass in the table, another inside a freezer and pour water in the third glass to a tumbler and place it over a heater. Instruct your students to monitor the activity and write down their observations. Continue the boiling till the entire water disappears. As soon as the water becomes ice take it from the freezer. Now show them each glass.
Take some wax and let your students write down the state in which it exists. First melt the wax by placing it over fire and then cool it till it changes into solid state. Let them write down the present state of wax in each case.
Show your students some sticks and prepare a fire in the ground. Once the fire extinguish, take small pieces of charcoal in the shape of stick.
Analysis and conclusion:
Children will understand that water changes into ice when temperature is lowered and into vapor when temperature is raised. From the second activity they will understand that, change of state occur in the case of materials other than water. The third activity shows that the entire character of some materials are lost on heating. They will understand that even though some materials change from one state to another on heating , it is not a general case.
