Who Invented the ELEVATOR?

ELEVATOR

The man who solved the elevator safety problem, making skyscrapers possible, was Elisha Otis, who is generally known as the inventor of the modern elevator. In 1852, Otis came up with a design that had a safety "brake."May 2, 2014

 

ELISHA OTIS

 

Science Lesson about breezes!!!

Land and Sea Breezes

As the names suggest, the two breezes occur along coastal areas or areas with adjacent large water bodies. Water and land have different heating abilities. Water takes a bit more time to warm up and is able to retain the heat longer than land does.

Now let us see the two diagrams below:

In the day, when the sun is up, the land heats up very quickly and the air above it warms up a lot more than the air over the water. The warm air over the land is less dense and begins to rise. Low pressure is created.

The air pressure over the water is higher with cold dense air, which moves to occupy the space created over the land. The cool air that comes along is called a sea breeze.


In the night, the reverse happens. The land quickly loses its’ heat whiles the water retains its’ warmth. This means the air over the water is warmer, less dense and begins to rise. Low pressure is created over the water. Cold and dense air over the land begins to move to the water surface to replace the warmer rising air. The cool breeze from the land is called a land breeze.






Mountain and Valley Breezes

In a similar behavior as land and sea breezes, mountains (hilly) and surrounding valleys also have breezes called Mountain and Valley Breezes.


During the day, the air over the mountain slope heats up more than the air at the foot of the mountain. The warm air over the slope reduces in density. A low pressure is created at the top of the mountain and high pressure from the cool air below forces a cool breeze to move upward. This condition generates a breeze which we call Valley breeze, and it is very common during warmer months when there is a lot of heating from the sun.


In the night, it is a lot cooler as the sun goes to sleep. So the air at the upper slope of the mountain cools off very quickly and becomes dense. A high pressure is created. At this time, the air at the valley floor is a lot warmer (low pressure) and is forced to give way to colder air moving down the slope towards the valley floor. This is called mountain breeze, and it is a lot common in the colder months when there is less warming from the sun.

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