Foliated Texture A foliated metamorphic rock will have banded minerals. The mineral flakes will appear to be parallel to the rock and will look layered. When a foliated rock breaks, a thin rock fragment will result.

High-grade metamorphism takes place at temperatures greater than 320oC and relatively high pressure. As grade of metamorphism increases, hydrous minerals become less hydrous, by losing H2O and non-hydrous minerals become more common.

Metamorphic rocks form when heat and pressure transform an existing rock into a new rock. Contact metamorphism occurs when hot magma transforms rock that it contacts. Regional metamorphism transforms large areas of existing rocks under the tremendous heat and pressure created by tectonic forces.

Three types of metamorphism exist: contact, dynamic, and regional. Metamorphism produced with increasing pressure and temperature conditions is known as prograde metamorphism.

AGENTS OF METAMORPHISM – The agents of metamorphism include heat, pressure (stress), and chemically active fluids. During metamorphism, rocks are often subjected to all three metamorphic agents simultaneously.

The 3 main factors that affect barometric (air) pressure are: Temperature of air. Altitude or Elevation.

Temperature, pressure, volume and the amount of a gas influence its pressure.

about 14.7 pounds per square inch

Commonly used in the U.S., but not elsewhere. Normal atmospheric pressure is 14.7 psi, which means that a column of air one square inch in area rising from the Earth’s atmosphere to space weighs 14.7 pounds. Normal atmospheric pressure is defined as 1 atmosphere. 1 atm = 14.6956 psi = 760 torr.

Air pressure is the pressure exerted by the air around us while Atmospheric pressure is the pressure exerted by the atmosphere on the earth. Air pressure is measured by tore gauge while atmospheric pressure is measured using mercury barometer.

There are two basic pressure types: absolute and gauge, distinguished by what pressure they are compared to, which is called the reference pressure.

Types of pressure: Absolute pressure, gauge pressure, differential pressure, Vacuum Pressure Sensor

• Absolute pressure. The clearest reference pressure is the pressure zero, which exists in the air-free space of the universe.
• Atmospheric pressure.
• Differential pressure.
• Overpressure (gauge pressure)
• Contact us.

Pressure Application Examples

A barometric reading below 29.80 inHg is generally considered low, and low pressure is associated with warm air and rainstorms.

Generally high pressure means fair weather, and low pressure means rain.

Some people may be more sensitive to weather changes experiencing more stiffness, pain, and swelling with a barometric pressure decline. Scientists suggest that a fall in air pressure allows the tissues (including muscles and tendons) to swell or expand.

Disregarding hypoxia, the lowest atmospheric pressure the human body can withstand is around 6 percent sea level pressure, or 61.8 millibars, below that pressure the water and blood in your body starts to boil.