6th grade Science test The Atmosphere

The percentage of oxygen in the atmosphere is approximately_______.

A gas in the atmosphere that varies in different places and from time to time is____.

Photochemical smog is caused by the action on chemicals of ______.

Harmful substances in air, water, or soil are called _____.

The amount of mass in a given volume of a substance is its _____.

As the density of air decreases, its pressure___.

Air pressure is often measured in ______.

The warmest layer of the atmosphere is the ______.

The layer of the atmosphere that reflects radio waves is the ______.

The stratosphere helps protect Earth from too much ultraviolet radiation because this layer of the atmosphere contains ______.

_______ is the most abundant gas in the atmosphere.

Particles of carbon that enter the air when wood or coal are burned are called ______.

One cause of acid rain is the burning of coal that contains a lot of ______.

_______ is the force per unit area.

The four main layers of the atmosphere are classified according ti changes in ______.

What is the condition of Earth's atmosphere at a particular time and place.

What to fires need to burn?

Has air quality improved over the past thirty years?

Does air pressure decrease as altitude decreases?

Do auroras occur in the atmosphere?

How is the density of air at the top of a mountain different that the density of air at sea level?

Why would you have more trouble breathing at the top of a mountain than the density of air at sea level?

Be able to describe how temperature in the atmosphere changes with altitude between the four main layers of the Earth's atmosphere.