Block 4 – Lesson 2

AIR CHARACTERISTICS

Why is the sky blue?

Why is the sky blue?

The elements of the air scatter blue light more efficiently than the other colors. That’s why the sky is blue.

Air is dissolved in the water of rivers, oceans, lakes and even the soil. It is part of the atmosphere that protects the Earth from sudden temperature changes and Sun rays.

Human beings breathe the air from the lower part of the atmosphere. Higher parts of the atmosphere are abundant in Ozone (O3) which is very important because it absorbs ultraviolet rays from the Sun

PHYSICAL PROPERTIES OF AIR

•Air is odorless and tasteless.•Air has volume, and it expands and compresses.•Air has weight and presses on the surface of the Earth. This is called Atmospheric Pressure.•Air offers resistance that is the force that resists motion. Human beings use this resistance for navigation and windmills.•Air is colorless, but when the sunlight hits the atmosphere it appears as light blue.

PHYSICAL PROPERTIES OF AIR

Oxygen (21%)21%

Nitrogen (78%)78%

Carbon Dioxide (0.4%)0%

Argon (0.93%)1%

Others (0.17%)0%

AIR COMPOSITION

Oxygen (21%)21%

Nitrogen (78%)78%

Carbon Dioxide (0.4%)0%

Argon (0.93%)1%

Others (0.17%)0%

AIR COMPOSITION

•Oxygen: It is the most important gas for respiration in living things. It also aids combustion.

Oxygen (21%)21%

Nitrogen (78%)78%

Carbon Dioxide (0.4%)0%

Argon (0.93%)1%

Others (0.17%)0%

AIR COMPOSITION

•Oxygen: It is the most important gas for respiration in living things. It also aids combustion.

•Nitrogen: This gas, combined with oxygen, makes air more breathable. It supports pant growth and it is part of proteins in living things.

Oxygen (21%)21%

Nitrogen (78%)78%

Carbon Dioxide (0.4%)0%

Argon (0.93%)1%

Others (0.17%)0%

AIR COMPOSITION•Carbon dioxide: Air has a minimum amount of CO2. Living organisms produce it when they breathe. It is needed for photosynthesis.

•Oxygen: It is the most important gas for respiration in living things. It also aids combustion.

•Nitrogen: This gas, combined with oxygen, makes air more breathable. It supports pant growth and it is part of proteins in living things.

Oxygen (21%)21%

Nitrogen (78%)78%

Carbon Dioxide (0.4%)0%

Argon (0.93%)1%

Others (0.17%)0%

AIR COMPOSITION•Carbon dioxide: Air has a minimum amount of CO2. Living organisms produce it when they breathe. It is needed for photosynthesis.

•Oxygen: It is the most important gas for respiration in living things. It also aids combustion.

•Argon: It is a noble gas. A noble gas does not react with other gases.•Nitrogen: This gas,

combined with oxygen, makes air more breathable. It supports pant growth and it is part of proteins in living things.

DAWNDAWN is when the Sun comes up.DUSK is when the Sun goes down.