pressure
Definition
Pressure is the force exerted by a substance over a unit area. It is a scalar quantity, meaning that it has magnitude but not direction.
The SI unit of pressure is the pascal (Pa), which is equal to one newton per square meter (N/m^2).
Pressure can be caused by the weight of a substance, by the force of gravity, or by the movement of gas molecules.
The pressure of a substance can be increased by increasing the force applied, decreasing the area over which the force is applied, or increasing the density of the substance.
Pressure can be decreased by decreasing the force applied, increasing the area over which the force is applied, or decreasing the density of the substance.
Pressure is an important concept in physics and engineering. It is used to understand the behaviour of fluids, solids, and gases. It is also used to design machines and structures.
How can the word be used?
The pressure of the water on the hull of the ship was too great.
Different forms of the word
Noun: the force exerted on an object by another object.
Verb: to exert force on an object.
Adjective: relating to or caused by pressure.
Etymology
The word "pressure" comes from the Latin word "pressura", which means "pressing".
The first recorded use of the word "pressure" in English was in the 14th century.
Question
What might happen if the pressure of something is low?
AQA Science Exam Question and Answer
Question:
Define pressure in the context of fluids and gases and explain how it is calculated. Provide examples of how pressure is exerted in everyday situations and its significance in understanding atmospheric and water pressure.
Answer:
Pressure refers to the force applied per unit area on a surface by a fluid or gas. It is calculated by dividing the force applied on the surface by the area over which the force is distributed. Mathematically, Pressure = Force / Area.
Everyday situations illustrate the concept of pressure. For instance, when standing on one foot, your body weight is exerted over a smaller area, resulting in higher pressure on that foot. Inflating a balloon increases pressure inside, making the balloon taut.
Understanding atmospheric and water pressure is essential. Atmospheric pressure results from the weight of air molecules above a certain point on Earth's surface, with higher pressure at lower altitudes. Water pressure increases with depth due to the weight of the water above, making it a critical factor in deep-sea exploration and diving.
Comprehending pressure is crucial for various applications, from engineering to meteorology. It helps design structures to withstand external forces, predicts weather patterns, and ensures safety in underwater activities. By grasping the concept of pressure and its implications, we gain insights into the behaviour of fluids and gases in our surroundings.