Points to remember

Points to remember

* Everything in this world undergoes changes. Changes occur in position, shape, size, state, colour, temperature, composition etc.,

* Fast change – short period of time Slow change – long period of time

* Reversible change – can go back to its original state

* Irreversible change – cannot go back to its original state

* Desirable change - changes that are useful and harmless to our environmental

* Undesirable change - changes that are harmful to our environment.

* Natural change - changes that take place in nature on their own

* Human made change - changes that are brought about by human beings

* A solute when dissolved in a solvent makes a solution.

* The process of dissolving the solute in solvent is called dissolution.

Changes Around Us

ICT Corner

Through this activity you will be able to underst reversible & irreversible changes.

Step 1: Use the given URL in the browser. ‘Reversible and irreversible changes's page will open. Use the arrow marks on both sides of the substance to choose another substance to test.

Step 2: Click and drag the substance into the beaker, observe whether it dissolves or not. Click the Dissolving / Reversing button to switch between the both activities.

Step 3: In the Reversing activity, with some substances you can choose either to cool or to Heat them. With other substances you can choose either to Heat or to filter them by clicking the respective buttons.

Step 4: Click on the Reset button to clear.

Reversible and irreversible changes's URL:

http://www.bbc.co.uk/schools/scienceclips/ages/10_11/rev_irrev_changes_fs.shtml

*Pictures are indicative only