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History of the microscope
History of the microscope Teacherflix 4 Views • 2 years ago

In this video I would like to talk about the history of microscopes.During the 1590s, the two spectacle-makers, Hans and Zacharias Jansen began experimenting. They put lenses in a tube and made a very important discovery. They discovered that objects near the end of the tube appeared to be enlarged, much larger than any simple magnifying glass could achieve alone.

In the 1660’s Robert Hooke began looking at all kinds of objects with his microscope.
He put all of his drawings in a book called Micrographia
He is credited with naming cells but also studied items like fleas under his microscope.
Anton van Leeuwenhoek was very good at grinding and polishing lenses.
These lenses led to the building of his microscope which was considered the first practical microscope.
In 1674 Anton Van Leeuwenhoek was the first to see and describe bacteria.
Another huge advance in microscopes didn’t occur until German physicist Ernst Ruska and the electrical engineer Max Knoll constructed the prototype electron microscope in 1931, capable of four-hundred-power magnification.
Electron microscopes uses accelerated electrons in order to view objects.
Modern electron microscopes can magnify objects up to 10 million times

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How do hurricanes form over the Atlantic Ocean
How do hurricanes form over the Atlantic Ocean Teacherflix 5 Views • 2 years ago

Hurricanes also called tropical cyclones are amazing, powerful storms that can bring destruction and misery to an area hit by the hurricane. The Congressional Budget Office estimates that 1.2 million Americans live in coastal areas at risk of “substantial damage” from hurricanes
In this video I will look at the causes these tremendous storms?
In the northern hemisphere most hurricanes will begin to form around the equator off the coast of west africa.
The official hurricane season is between June 1 and November 3o
Why do hurricanes occur during this time period.?
The reason is that hurricanes need the ocean surface temperature to be at least 79-degree Fahrenheit.
In addition, you need high pressure above the hurricane and low wind shear.
Between June and November both of these conditions are meet often
Hurricanes are like giant engines that use warm, moist air as fuel. That is why they form over warm ocean waters near the equator. The warm, moist air over the ocean rises upward from near the surface. As the warm air rises a low-pressure system is created.
Air from surrounding areas with higher air pressure pushes into the low-pressure area. Then that "new" air becomes warm and moist and rises, too. As the warmed, moist air rises and cools off, the water in the air forms clouds. The whole system of clouds and wind spins and grows, fed by the ocean's heat and water evaporating from the surface
Tradewinds which blow across the equator help push the storm along.
The hurricane will rotate in an in a counterclockwise fashion in the north due to the Coriolis effect.
The Coriolis effect is caused by the earth's rotation and curves air in the northern hemisphere to the right.
The hurricane will continue to move across the ocean and pick up strength if the water temperature remains above 79 degrees, high pressure remains above the storm, and there is moisture to fuel the storm.
Hurricane strength is measured by wind speed and barometric pressure.
The minimum wind speed to be classified as a hurricane is 74 degrees and category 5 hurricanes have a wind speed greater than 157 miles per hour.
As a general guideline, September is the peak month for hurricanes because of the warm surface temperatures during this month.

Earthworm digestive system
Earthworm digestive system Teacherflix 6 Views • 2 years ago

Learn how the digestive system of an earthworm
http://www.moomoomath.com/eart....hworm-digestive-syst

How an earthworm digest the dirt it eats.
In this video, I review the digestive system of an earthworm. Earthworms may appear simple but are complex animals. Their digestion starts at the mouth and ends at the anus.

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-~-~~-~~~-~~-~-
Please watch: "Study Skills Teacher's Secret Guide to your Best Grades"
https://www.youtube.com/watch?v=f3bsg8gaSbw
-~-~~-~~~-~~-~-
*
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For more Life Science videos and summaries see,
http://www.moomoomath.com/Midd....le-School-Science-an

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