Unit: Science and TechnologyTopic: Air Pressure

vocabulary

air pressure

surface

vacuum

atmosphere

environment

Structure

Conjunction

A conjunction is a word that connects other words or groups of words.

There are conjunctions:

and but or that for also still elsebecause after if though before till unless aswhen where while since

and : we use and to connect the same type of word, phrase, or sentence.

For example:Atmospheric pressure varies slightly over the Earth's surface, and variations in pressure are responsible for the weather that we are so familiar with.

Low pressure is associated with storms, tornadoes, and hurricanes.

because : we use because when the sentences are cause and effect of each other.

For example:

We are able to survive this pressure because our bodies (and all life) evolved in an environment where it is omnipresent.

text

Text Air pressure, also known as atmospheric pressure, refers to the weight of the Earth's atmosphere pressing down on everything at the surface. The average air pressure at sea level is 101.325 kPa (1013.25 millibar), or 14.696 lbs/sq2 (1.0333 kg/cm2). Basically, this means hundreds of pounds of pressure are pressing at you from all sides and at all times. We are able to survive this pressure because our bodies (and all life) evolved in an environment where it is omnipresent. If the pressure is increased or decreased too much, we perish.

With pressure, as with a lot of things, it's all relative. Air pressure is why high-pressure machinery, such as hydraulics, require high structural integrity to contain the material —pressure has a tendency to equalize. It is also partially responsible for the phrase "nature abhors a vacuum," meaning a vacuum is hard to sustain under the pressure of Earth's atmosphere. Atmospheric pressure varies slightly over the Earth's surface, and variations in pressure are responsible for the weather that we are so familiar with. Low pressure is associated with storms, tornadoes, and hurricanes. Sometimes the air pressure at sea level can drop as low as 870 millibars, 85% of average air pressure. This only happens during the most severe storms. Pressure variations on the Earth surface cause wind: high pressure areas have a tendency to seek out low pressure areas, causing gusts.

Egg in bottle

You will need -glass bottle-boiled egg-match -a piece of paper

glass bottle

boiled eggs

match

a piece of paper

It’s time to do the experiment!

-make a group of four students.-the representative of each group comes in front

of the class to take the material.-do the experiment.-report the result of the experiment in front of

the class.

1.Draw the steps of the experiment

2. Result of the experiment………………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………3. The problem of this experiment……………………………………………………………………………………………………………………………………...

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Egg in bottle