Pressure is defined as a continuous force to the surface area across which it is applied. Because pressure is thrust per unit area, it is directly proportional to force and inversely proportional to area. Its formula is force/area. As per studies, as an object moves higher in altitude the pressure experienced by the object decreases; this is caused due to thinning of the atmosphere and less air being present at higher altitudes. To understand what are the factors pressure depends on and why pressure change with height, keep on reading.
1. What is called Pressure?
The physical force applied to an object is referred to as pressure and the force applied is perpendicular to the per unit surface area of the object. The formula for pressure is force per unit area which is written as:-
Pressure = Force/Area
The different types of pressure are atmospheric, differential, gauge pressures, etc. In the physical sciences, pressure is also referred to as the stress at a point within a confined fluid or the perpendicular force per unit area. (See How can you measure air pressure?)
2. What is the SI unit of Pressure?
Newton’s unit of force is Newton and sq.m or m^{2} is how we represent the area.
Thus, N/m^{2} is the unit of pressure as Pressure = Force/Area.
The SI unit of pressure is called Pascal and One Newton per square meter is equivalent to one Pascal(Pa). This name was surprisingly given in 1971. Before this, the SI used was Newton’s per square meter to measure pressure. (See How Is Energy Measured?)
3. Why do you measure Pressure?
Before we discuss the types of pressure, let us first understand the reason why we measure pressure. Measurement of a substance’s pressure plays a significant role in the production process across a variety of sectors. To assess the product’s consistency and quality, it’s critical to collect precise data. For these reasons, precise sensors are essential for gathering this data, eg: The Pascal- N/m^{2}, or the Kilopascal(kPA) where 1 kPa = 1000 Pa. Pressure is often given in pounds per square inch in the English system which is psi. (See How can You measure Temperature?)
4. What are the Types of Pressure?
The force applied per unit area is described as pressure. Different types of pressure are:-
- Absolute pressure: It is the pressure that is connected to reference pressure. An object’s pressure has been measured using the pressure at absolute zero as a reference. The total of the gauge pressure and atmospheric pressure is another way to describe it. Therefore, the value of absolute pressure is always positive since the gauge pressure value cannot be lower than the absolute zero pressure. External influences like weather conditions or height will not change the absolute pressure.
- Differential pressure: The differential pressure is equal to the difference between the two pressures. The difference in pressure between any two places is exactly what differential pressure is.
- Atmospheric pressure: It is the force that is exerted by the earth’s atmosphere. This pressure is affected by altitude and climate. It is sometimes known as barometric pressure.
- Gauge pressure: This is the difference between absolute and atmospheric pressures. Gauge pressure is the pressure that we measure keeping atmospheric pressure in mind. Gauge pressure above atmospheric pressure is positive, and gauge pressure below atmospheric pressure is negative. It is a pressure that is frequently used in the technological field.
- Absolute zero pressure: When measuring pressure, we use absolute zero pressure as our basis or reference point. Zero is the value of pressure at absolute zero, which is also known as the pressure of a vacuum. Pressure lower than the pressure at absolute zero cannot be defined.
- Ambient pressure: This term refers to the pressure exerted by the liquid or gas around the object when it is placed in that medium.
- Vacuum pressure: Vacuum pressure is the measurement of pressure that is below atmospheric pressure. As a result, the vacuum pressure is represented by the gauge pressure’s negative value. It is measured with a reference to a sealed chamber that is closed with atmospheric pressure.
5. What are the Factors Pressure depends on?
Now that we gained an insight into the types of pressure, let us look at the factors that pressure depends on. Pressure is a force applied to a surface in a specific region. Thus, the pressure relies on the area of the surface and the applied force on the object. Must read what does a Barometer measure?
6. Is Pressure depend on Area?
The thrust/force acting on a surface’s unit area is referred to as pressure. Therefore, the amount of force that is applied to a surface and the area of that surface are the factors that affect the pressure, hence pressure depends on area. (See What Instrument is Used to Measure Mass of an Object?)
7. Is Pressure a Force?
You are now aware of what are the factors pressure depends on, so, is pressure a force? Pressure can be defined as the physical amount of force applied to a certain region which can be denoted as force per unit of area. The pressure exerted on a body may be estimated by dividing the amount of force exerted by the area of contact. (See What Type of Energy is produced by Friction?)
8. Does Pressure depend on Force?
Pressure depends on the force and surface area which also give out its formula, i.e. Force/Area. Pressure depends upon the factors like the area over which force is applied and how much it is applied.
9. Is Pressure dependent on Density?
Pressure is observed to be directly proportional to density and inversely proportional to temperature, which means if the temperature decreases and pressure have increased, then the density will also increase and vice-versa. This indicates the direct proportionality and dependence of pressure and density. (Also read Weight of Earth and Moon)
10. Does Pressure change with Height?
Yes, pressure change with height as pressure decreases with increasing altitude. The pressure exerted on an object at any level is the weight of air molecules on the object and as you move higher there are fewer and fewer air molecules present. This happens because the gravitational force that holds the air molecules, is stronger when they are closer to Earth’s surface and as an object moves higher, the gravitational force gets weaker which results in a decreasing pressure. (See What are the Properties of Air?)
11. What Pressure is Vacuum?
A vacuum is a space that has been artificially emptied to the greatest extent feasible such as an air pump. This term refers to a strong or hard vacuum. The amount of pressure within the container that is less than the amount of pressure outside is referred to as vacuum pressure. If the damage is caused by a pressure differential, the vacuum pressure indicates that the force is directed inside the container.
Pressure is crucial in many aspects of daily life, including the operation of pumps and hydraulic presses. Though solids apply pressure, the most fascinating instances of pressure include fluids like gases and liquids, including water and air. The preservation of normal air pressure is critical to human health and well-being, the body is completely adapted to the normal pressure of the atmosphere, and if that pressure is drastically disturbed, a person may suffer detrimental or even deadly side effects. Therefore, by now, you must have understood what is pressure, the factors pressure depends on, and the importance of pressure. (Also read Which Instrument is used to Measure Wind Speed?)