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That depends on the 'tube' involved.
In a thermometer the Mercury expands and contracts within a sealed tube as the temperature is raised or lowered.
In a barometer there is a reservoir of mercury which the atmosphere presses on. This maintains the mercury in a column which is sealed at the top. Increases in atmospheric pressure push the mercury further up the tube, decreases let it drop down the tube.
Wiki User
∙ 15y ago
Wiki User
∙ 14y agothe air off of mercury has a big tube in the inside of it and it pushes in up
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How does a barometer work?
There are a couple of types. By far the most common is the aneroid barometer. The heart of an aneroid barometer is a sealed can. As the surrounding pressure rises and falls, the can shrinks and expands. A mechanical linkage translates the deflection into the movement of a dial. It could also be measured with a strain gauge, with the resistance translated into pressure.The Mercury barometer has a tube sealed at the top, full of mercury sitting in a cup full of mercury. A vacuum forms at the top because the exterior pressure can only support a column equal to the height times the density of mercury.Air pressure pushes on the mercury inside of the container, the mercury moves up the glass tube. The greater the air pressure the higher the mercury will rise.
Who discovered atmospheric pressure?
Evangelista Torricelli discovered atmospheric pressure. Secretly, he created an expierement with some of his friends. By filling a bowl with mercury and placing a six foot long glass tube upside down into it, a vacuum was created, causing the mercury to rise up. This was an early barometer. The reason this expierement was kept secret was probably because in 1643, this would have been considered witchcraft because a vacuum was considered impossible.
Where can i buy liquid mercury from?
Firstly a barometer does not use mercury to measure atmospheric pressure.Secondly you need to have a license to handle mercury since it is a very dangerous material.Some barometers do use mercury, but not to directly measure the atmospheric pressure. It was used because air did not mix with the mercury because of the density.So the air would "push down" on the mercury, pushing it up another tube that had a measuring system on it, usually metric.This is where we get the pressure unit Torr, which is 760mmHg, which is 1 ATM (atmosphere), the pressure at sea level.
What is the principle of operation of fluorescent?
The tube is filled with noble gas (i.e. argon, neon, helium). The tube also contains a small amount of mercury that when heated becomes mercury vapor. The inside of the tube is lined with phosphorescent material (mostly phosphorous). In the base of the bulb is an electronic ballast that boosts the line voltage up high enough to ionize the gas inside the bulb. As this happens the mercury also vaporizes inside the tube. The ionized gas and ionized mercury vapor emit ultraviolet light which strikes the phosphorous. The phosphorous, in turn, emits white light that lights up the room.
How is a neon sign repaired?
It could be several issues that affect the sign... It could be a burned gto wire going from the transformer to the tube, or it could be a burnt up transformer, or a broken neon tube. Typically, the neon tube is removed from the sign. If it is a red gas tube, it can be repaired by bending up the missing section, and welding it with fire back together. Then it must be pumped (bombarded) If the tube is green, blue, white, yellow, or any other color that uses Mercury to aid its light output when originally lit, then great care must be taken. Vaporizing mercury is very toxic to the health of neon workers and this type of tube needs to be made new, with the old tube being properly disposed. I have fixed a few mercury tubes, but I do not advise it to anyone. If the state finds out where mercury tubes are being repaired, they can come close you down if they find loose mercury or contaminated premises, or worse... do something that affects the title to your property!!
What pushes mercury up a tube in a mercury barometer?
the air off of Mercury has a big tube in the inside of it and it pushes in up
Why doesn't Mercury boil in the vacuum tube of a barometer?
there must be vacuum in the Mercury barometer because if air enters the tube the barmeter would become faulty as air pressure will change.
How does high pressure area effect a mercury barometer?
Higher air pressure forces the mercury farther up the tube.
How does a barometer work?
There are a couple of types. By far the most common is the aneroid barometer. The heart of an aneroid barometer is a sealed can. As the surrounding pressure rises and falls, the can shrinks and expands. A mechanical linkage translates the deflection into the movement of a dial. It could also be measured with a strain gauge, with the resistance translated into pressure.The Mercury barometer has a tube sealed at the top, full of mercury sitting in a cup full of mercury. A vacuum forms at the top because the exterior pressure can only support a column equal to the height times the density of mercury.Air pressure pushes on the mercury inside of the container, the mercury moves up the glass tube. The greater the air pressure the higher the mercury will rise.
Why doesn't mercury boil in the vacuum of a barometer?
Becuase the presure just pushes it up and down so it couldn't boil because it would always be moving
How can you prove that atmosphere exerts pressure?
The original experiment that demonstrated this was a portable Mercury column.If you have a large bowl full of Mercury (a liquid metal) and a 1 meter long glass tube open at one end, then you can make a simple barometer. First, completely fill the tube with mercury, and temporarily close of the open end of the glass tube with a fitted seal, so the glass tube will be completely full of mercury and closed at both ends. Then stand the inverted tube (with its sealed end in the bowl of mercury), and while the end of the tube is immersed in the mercury, remove the fitted seal, allowing the mercury trapped inside the tube to flow into the bowl. Some of the mercury will flow out of the tube into the bowl, but the air pressure will cause the remaining mercury remain in the tube up to a height of (about) 760 mm above the mercury level in the bowl. The volume in the tube above the column of mercury will be filled with a vacuum..If you were to then take your portable barometer on a hike up a mountain, you would notice that the volume of the vacuum in the tube would become greater, and the column of mercury in the tube become shorter. This is because the atmospheric pressure keeping the mercury up the tube is lower at a higher altitude..Note: Mercury is a dangerous substance and must be handled with care. The above experiment should not be attempted except under the supervision of qualified laboratory personnel..See the related link below.
What is a baromeater?
A barometer measures atmospheric pressure. The air in the atmosphere exerts a force called pressure that constantly changes due to moving weather systems. Therefore, in conjunction with other meteorological instruments, a barometer helps to predict clear or rainy weather. In 1643, Evangelista Torricelli invented the first barometer. He figured that if he had a vacuum, an airless space, he could compare the ever-present atmospheric pressure with zero pressure. So he placed a vacuum contained in a glass tube on top of a larger container of mercury. The air presses down on the mercury's exposed surface and pushes it up into the tube. The higher the mercury level, the greater the air pressure. Originally, the units of air pressure were just millimeters of mercury. People could finally measure the force of air
When air pressure goes up the liquid in a mercury barometer goes?
rises
Where does the atmosphere exert pressure on?
Basically, because the atmosphere has weight. There would be no weight without gravity. Earth's gravity is pulling the atmosphere down toward earth's surface. We live on the surface, so the atmosphere pushes on us.
Describe how a mercury barometer measure air pressure?
The basic principle of barometer is Torricelli's experiment. Imagine that you fill a tube of one metre length (100cm) with mercury up to the brim. Then close the mouth of the tube with your thumb and invert the tube and place it in a cistern of mercury with its end immersed in the mercury say some 4 cm. Now you remove your thumb. Mercury would come down but it stops at one level to our astonishment. This level would be some 20 cm from the closed end of the tube. So there will be almost 76cm column of mercury in the tube. Why is it so? As mercury comes down the space left vacant will not be having any air molecule and so it is almost vacuum. This is named as Torricelli's vacuum. Now the air outside in the atmosphere would exert a pressure and wants to push the mercury towards this vacuum place. But the weight of the mercury column (76cm) will balance this pressure. Hence we say the atmospheric pressure will be 76 cm of mercury. This is how we have mercury scale for measuring the pressure. Usually pressure is defined as the force per unit area. Hence the unit will be N/m2 or pascal. But we give pressure only in cm or mm of mercury. The reason is explained properly. Same technique is applied in Fortin's barometer and vernier arrangement is made to measure the pressure so accurately.
Why is mercury in a thermometer stored in a narrow tube?
Like most materials, mercury expands when heated. By storing the mercury in a narrow tube, as the mercury gets warmer (and therefore expands) it will rise up the tube, allowing the temperature to be determined based on how high up the tube the mercury has risen.
Who discovered atmospheric pressure?
Evangelista Torricelli discovered atmospheric pressure. Secretly, he created an expierement with some of his friends. By filling a bowl with mercury and placing a six foot long glass tube upside down into it, a vacuum was created, causing the mercury to rise up. This was an early barometer. The reason this expierement was kept secret was probably because in 1643, this would have been considered witchcraft because a vacuum was considered impossible.
