1. Atmospheric pressure.

2. Introduction All objects on Earth are affected by the force of atmospheric pressure. The force of atmospheric pressure is created by the weight of air. Air is not the name of a chemical element or gas. Air is a non-scientific term for a mixture of many different gases. The atmosphere is a layer of different gases surrounding our planet. Even though air seems weightless, it does have a weight. The Earth's atmosphere is about 500 kilometres deep. That is a lot of air! This air pushes down, with its weight, everything on Earth, creating atmospheric pressure.

3. What is Atmospheric Pressure ? Atmospheric pressure is the pressure exerted by the weight of air in the atmosphere of Earth (or that of another planet). OR Atmospheric pressure is defined as the force per unit area exerted against a surface by the weight of the air above that surface. How is it measured ? It is measured with a barometer,in barometer the level of mercury rises or falls as the weight of atmosphere changes.

4. What is the unit used to measure it? An atmosphere is the unit of measurement equl to the average air pressure at sea level at a temperature of 15 degree celsius. One atmosphere is equal to 1.013 millibars. In aviation and television weather reports, pressure is given in inches of mercury ("Hg), while meteorologists use millibars (mb), the unit of pressure found on weather maps

5. How does the decrease in atmospheric pressure affect us? As the atmospheric pressure decreases,the amount of oxygen available to breathe also decreases.so at high altitudes as at.pressure decreases the people can becme sick and can die also. Mountain climbers use bottled oxygen when they ascend high peaks. Moving quickly from higher to lower pressure can cause ‘decompression sickness’ (or the bends ‘)

6. Can atmospheric pressure indicate weather ? When a low pressure area moves into an area,it usually leads to cloudiness,wind and precipitation. high pressure systems usually lead to fair calm weather.