Points to Remember

Points to Remember

* Air is all around us.

* Our earth is surrounded by a huge envelope of air called the atmosphere.

* The process of burning of a substance in the presence of oxygen and releasing a large amount of light and heat is called combustion.

* Priestley helped us in understanding the presence of oxygen in air that is produced by plants during photosynthesis which can be used by animals for respiration.

* Ingenhousz experiment helped us to know the role of sunlight in evolving Oxygen during photosynthesis.

* Air contains 78% Nitrogen, 21% Oxygen, 1% of carbon-di-oxide, water vapour, Noble gases, and dust particles.

* Composition of air changes slightly from place to place and also from season to season.

* In plants,

Carbon-di-oxide +water ---- ^{Sunlight Chlorophyll}→ Food + Oxygen Chlorophyll

* In animals,

Food + Oxygen → Carbon - di - oxide + water + Energy

* Aquatic plants and animals use oxygen dissolved in water for breathing.

* Ozone layer, present in the atmosphere helps in preventing harmful radiations hitting the earth directly.

ICT Corner

Air

Through this activity you will be able to understand the atomic level of the process that plants use to convert solar energy into chemical energy.

Step 1: Use the given URL in the browser. ‘Illuminating Photosynthesis page will open.

Step 2: Three buttons given on the top of the activity window to explore. Click the 'The Cycle' button, in this window you can open the curtain and water the plant by click on the curtain and the watering pot.

Step 3: Explore the atomic level process of the photosynthesis by clicking the 'Atomic Shuffle' button.

Step 4: Click 'Replay" to view the process again and 'Next' to view the next level of the process.

Illuminating Photosynthesis URL:

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

*Pictures are indicative only