How many types of gravimeters are there?
two types
There are two types of gravimeters: absolute and relative. Absolute gravimeters measure the local gravity in absolute units (“Gal” after “Galileo”). Absolute gravimeters are compact (Autograv CG-5 model) and used in the field. It works by directly measuring the acceleration of a mass during free fall in a vacuum.
What are stable and unstable gravimeters?
In a stable device, once the system has been disturbed it will return to its original position, whereas an unstable device will move further away from its original position. For example, if a pencil lying flat on a table is lifted at one end and then allowed to drop, the pencil will return to being flat on the table.
What is a stable gravimeter?
An instrument that uses a high order of optical and/or mechanical magnification so that an extremely small change in the position of a weight or associated property can be accurately measured.
What is gravimeter used for?
gravimeter, also called gravity meter, sensitive device for measuring variations in the Earth’s gravitational field, useful in prospecting for oil and minerals. In one form, it consists of a weight suspended from a spring; variations in gravity cause variations in the extension of the spring.
What is satellite gravimetry?
The Institute of Geodesy has been working on satellite-based gravity data for years. The spectrum of activities ranges from the calculation of regional (and global) gravity field solutions to extensive data analysis and studies of geophysical phenomena such as permafrost in Siberia.
How sensitivity of unstable gravimeter is increased in comparison to stable type?
Stable-type meters provide gravity readings which are linear over relatively wide ranges of scale reading. Unstable meters are usually nonlinear but generally have higher sensitivities. The sensitivity of an unstable gravimeter can be increased by lengthening its natural period of oscillation.
Is there a way to measure gravity?
A gravimeter is an instrument used to measure gravitational acceleration. Every mass has an associated gravitational potential. The gradient of this potential is a force. A gravimeter measures this gravitational force.
What is absolute gravity?
The value that denotes the density or specific gravity of a fluid at standard conditions; for gases, these conditions are standard atmospheric pressure (760 mmHg) at 0º C.
Is gravity different than underground?
Gravity is what holds our world together. However, gravity isn’t the same everywhere on Earth. Gravity is slightly stronger over places with more mass underground than over places with less mass.
What are the two types of gravimeters?
There are two types of gravimeters: absolute and relative. Absolute gravimeters measure the local gravity in absolute units (Gal). Absolute gravimeters are compact (Autograv CG-5 model) and used in the field. They work by directly measuring the acceleration of a mass during freefall in a vacuum.
Which is the most suitable gravimeter for mobile use?
It is the most suitable gravimeter for mobile use. Spring-based gravimeters measure only relative gravity by analysing the response of a spring to an attached mass acting in a gravitational field. They are often used in gravity surveys over large areas as they are compact, transportable systems with good sensitivity and drift rate.
What are the types of absolute free-fall gravimeters?
The types of absolute free-fall gravimeters are: Falling corner-cube gravimeter – The motion of a free falling corner-cube retroreflector in vacuum is monitored by a laser interferometer, which detects optical interference to determine the rate of acceleration of gravity.
What does an absolute gravimeter measure?
Absolute gravimeters measure the rate at which a mass in free fall in a vacuum accelerates. A retroflector is used with a Michelson interferometer to count and time interference fringes and thus measure the acceleration of the mass. The types of absolute free-fall gravimeters are: