Features of air

3 “v” class, Krasimira Krondeva and Natasha DjurkovaSOU Ekzarh Antim IKazanlak, Bulgaria

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Life is impossible without the air we breathe.It is everywhere around us. The air posses a number of features:

colourless gas; penetrates everywhere; has no taste; has no smell; has weight; fulfills space; lighter than water; keeps the fire burning.

With the help of the next experiments we will prove some of it`s features.

Feature 1:The air fulfills space

Necessary materials:big vessel full of water,glass cup,a piece of newspaper

Try 1:Place at the bottom of the cup the newspaper, smashed into a ball.After that dive the whole cup in the water. After a time pull the cup out,without tilting it.

Goal:After you take the cup out, the newspaper must stay dry because the air doesn`t let the water pervade.The air fulfills space.

Try 2:Place at the bottom of the cup the newspaper, smashed into a ball. After that dive the whole cup in the water. After a time pull the cup out,but this time tilt the cup.Are there any bubbles coming out?

Conclusions:1.There is air in the bubbles coming out out of the cup;2.This time the newspaper will get wet,because the air,which has

come out,has set free a space.

Air Pressure Water and Gravity

Materials: a simple beaker and an index card

Action:

Fill the beaker with water. Then place the card on top of it

Hold the card with your hand and hold the beaker.

You probably expect that the water will push the card and will spill all over but it doesn't.

This is because the air has pressure which pushes the card to stay in place. Moreover, the beaker has

a perfect seal and the air doesn't penetrates in the beaker.

Air Pressure Stops the Water In the Bottle

Materials: a water bottle and a pushpin

Action:The bottle is full of water.

Create a hole in the bottle with the pin.

The water doesn't come out.

What will happened if you open the cap?

the water will start coming out

This is because of the cap, which stops the air from getting in the bottle and pushing down on the liquid. Take the cap off. The air comes in and forces the water out. When you put the cap back, the liquid stops flowing from the hole. This is because the air from the outside pushes on the hole and when the cap is off the air applies pressure on the water and the water comes out from the hole.

How to get a coin out of water without getting wet

Materials: a plate, a coin, a glass cup and a candle

Action: Place a little water in the plate.

If you want put some paint in the water so that you can see the try better. Then put the coin in it.

Put the candle at the middle of the plate

Light the candle

After that place the glass cup on top of it.

The heated air in the cup will soak up the water.The coin is dry and you can take it without getting wet.

The air has weight

Necessary materials: scales(light stick,hanged to the middle with

thread),2 balloons

To the two ends of the stick tide 2 equally inflated balloons, so that the scales can be balanced. Then discharge the air in one of the balloons. To which side do the scales tilt?

Conclusion:The scales tilt to the side with the inflated balloon, because the air has weight.

Greenhouse

The greenhouse makes the life on Earth possible.The natural hothouse gases like water vapor(H2O),carbon dioxid(CO2),a smal quantity of methane(CH4), nitrous oxide (N2O) and troposferic ozone(O3) allow the sun energy to penetrate and reach the Earth,and then seize it as an infrared heat.This phenomen keeps our planet warm enough so that all living organisms may function physiological. The lack of greenhouse would reduce Earth`s temperature with about 33o C,turnig it into a planet with no life.Unfortunately over the last century the greenhouse has become serious threat,because of its augmentation as a result of man`s activity.The industrialization and the continued growth in the population rapidly increase the issues of hothouse gases by burnig organick fuels,cutting down forests and clearing areas for farming purposes.These extra permanent sources upset the delicate balance,as considerably increace the quantity of hothouse gases in the atmosphere and increase their warming effect.As a result there is change in the klimath,a direct influence on human health and changes in the environment.

Necessary materials for making greenhouse:

Two jars with screw caps Two thermometers(which can be put inside the jars) Aluminium folio Black pasteboard Chronometer

Action:

1.Envelop jar 1 with folio from the outside.2.Envelop jar 2 with black pasteboard from the inside.3.In both jars put a thermometer,then close them with a screw.4.Begin to cut time(3 minutes).5.Watch and see!