Air pressure.

flight-club

3 Sept 201403:35

Summary

TLDRThis educational video script explores the physics of flight, focusing on air pressure. It explains that air, composed of molecules with mass and weight, exerts pressure on objects due to its fluid-like behavior. The script distinguishes between static and dynamic air pressure, using examples like balloons and moving buses to illustrate the concepts. It then connects these principles to aerodynamics, showing how an airplane's wing shape utilizes the Bernoulli principle to create lift by reducing air pressure above the wing while maintaining higher pressure below, allowing flight.

Takeaways

🛫 The script explains the physics behind how an aeroplane stays up in the air.
🌬️ Air is composed of small molecules made up of even smaller atoms, which give it mass and weight.
💨 Air behaves like a fluid and exerts pressure on objects it comes into contact with.
🎈 An inflated balloon doesn't get squashed by static air pressure because the air inside balances the pressure outside.
📉 A decrease in static air pressure outside can cause a balloon to expand.
🚌 Dynamic air pressure is experienced when an object moves through air, like wind resistance felt when sticking your head out of a moving bus.
🔄 The total air pressure is the sum of static and dynamic air pressures, and they inversely affect each other.
🌀 Airflow through a tunnel demonstrates how narrowing the tunnel increases airspeed and dynamic pressure, while decreasing static pressure.
📉 Faster airflow over a surface results in lower static pressure, a principle utilized in the design of aeroplane wings.
✈️ Lift on an aeroplane wing is created by the higher air pressure below the wing compared to the lower pressure above, which allows the aircraft to fly.

Q & A

What is the primary reason an airplane can stay up in the air?
-An airplane can stay up in the air due to the difference in air pressure above and below its wings, which creates lift.
What are the two types of air pressure discussed in the script?
-The two types of air pressure discussed are static air pressure and dynamic air pressure.
How does static air pressure affect an object at rest?
-Static air pressure exerts a constant force on an object at rest, which is balanced by the air pressure inside the object, such as in the case of an inflated balloon.
What happens to a balloon if the static air pressure outside decreases?
-If the static air pressure outside decreases, the balloon will expand to fill in the space because the internal pressure is greater than the external pressure.
How is dynamic air pressure experienced by an object?
-Dynamic air pressure is experienced by an object when it moves through the air, such as when sticking your head out of a moving bus and feeling wind resistance.
What is the relationship between static and dynamic air pressure as described in the script?
-For a constant value of total air pressure, if dynamic air pressure increases, static air pressure must decrease, and vice versa.
Why does the speed of air increase inside a thinner section of a tunnel?
-The speed of air increases inside a thinner section of a tunnel because the same volume of air has less space to pass through, resulting in higher velocity.
How does the shape of an airplane wing relate to the concept of static air pressure in a tunnel?
-The shape of an airplane wing is designed to mimic the surface area in a tunnel where lower static air pressure occurs, which helps in creating lift.
What is the Bernoulli's principle as it relates to the lift on an airplane wing?
-Bernoulli's principle, which is not explicitly mentioned in the script, states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. This principle is responsible for the lift on an airplane wing, where faster airspeed over the top of the wing creates lower pressure compared to the slower airspeed underneath.
Why does the airplane need to move fast enough through the air to generate lift?
-The airplane needs to move fast enough to generate the necessary airflow over and under the wings, creating the pressure differential that results in lift.
How does the script explain the concept of air having mass and weight?
-The script explains that air, made up of many small molecules and atoms, has mass and therefore weight, behaving like a fluid and exerting pressure on objects it comes into contact with.

Outlines

00:00

🛫 Aerodynamics and Air Pressure

This paragraph introduces the fundamental physics behind how airplanes stay aloft. It explains the concept of air pressure by discussing the properties of air, which is composed of molecules made up of atoms. These air molecules exert pressure on objects they come into contact with. The script distinguishes between static air pressure, which acts on stationary objects, and dynamic air pressure, which occurs when an object moves through the air. The relationship between static and dynamic air pressure is illustrated through the example of a balloon and the sensation of wind resistance when sticking one's head out of a moving vehicle. The paragraph concludes with an explanation of how the total air pressure is the sum of static and dynamic air pressures.

Mindmap

Keywords

💡Air Molecules

Air molecules are the basic building blocks of air, composed of many tiny atoms. These molecules are invisible to the naked eye but have mass and weight. In the context of the video, air molecules are essential in understanding air pressure and how it affects objects, such as an airplane in flight. The video explains that air molecules exert pressure on objects they come into contact with, which is a fundamental concept in the physics of flight.

💡Air Pressure

Air pressure is the force exerted by air molecules on a surface. The video script explains that air pressure is a result of the weight of air molecules and is crucial in understanding how objects like airplanes stay aloft. It is divided into static and dynamic air pressure, which together make up the total air pressure. The video uses the example of a balloon to illustrate how air pressure works: the air inside the balloon balances the pressure outside, preventing it from being squashed.

💡Static Air Pressure

Static air pressure is the pressure exerted by air on an object when it is stationary. The video script uses the example of an inflated balloon to explain static air pressure, where the air inside the balloon balances the pressure from the outside air, preventing the balloon from being crushed. This concept is integral to understanding how wings generate lift, as the pressure above the wing is reduced compared to the pressure below.

💡Dynamic Air Pressure

Dynamic air pressure is the pressure experienced by an object moving through the air. The video script mentions that when you stick your head out of a moving bus, the wind resistance felt on your face is an example of dynamic air pressure. This pressure is created by the object's movement through the air and is a key factor in the lift generated by airplane wings.

💡Total Air Pressure

Total air pressure is the sum of static and dynamic air pressures. The video script explains that for a constant value of total air pressure, if dynamic air pressure increases, static air pressure must decrease, and vice versa. This concept is important in understanding the Bernoulli's principle, which is used to explain how airplanes generate lift.

💡Airflow

Airflow refers to the movement of air through a space, such as a tunnel or around an object like an airplane wing. The video script describes how airflow changes when the width of a tunnel is reduced, leading to an increase in air speed and dynamic air pressure, while static air pressure decreases. This principle is applied to explain how the shape of an airplane wing creates lift by reducing air pressure above the wing.

💡Lift

Lift is the upward force that opposes the weight of an object, such as an airplane, and allows it to stay in the air. The video script explains that lift is created by the difference in air pressure above and below an airplane wing. The faster airflow and reduced static pressure above the wing compared to the slower airflow and higher pressure below the wing generate lift, enabling the aircraft to fly.

💡Wing Shape

The shape of an airplane wing is designed to create lift. The video script describes how the shape of the wing's surface, similar to the tunnel's surface where lower static air pressure is observed, contributes to the generation of lift. The curvature of the wing forces air to move faster over the top of the wing, reducing pressure and creating lift.

💡Bernoulli's Principle

Bernoulli's Principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure. The video script alludes to this principle when explaining how lift is generated by the faster airflow over the top of an airplane wing, which results in lower air pressure compared to the slower airflow underneath the wing. This principle is fundamental to the physics of flight.

💡Atmosphere

The atmosphere is the layer of gases surrounding the Earth. The video script mentions the Earth's atmosphere as the environment where air molecules exist and exert pressure. The atmosphere is crucial for flight as it provides the medium through which airplanes generate lift and maintain altitude.

💡Fluid

In the context of the video, air is described as behaving like a fluid. This is because air, like water, can flow and exert pressure on objects. The video script uses the analogy of air behaving like water to help explain concepts such as air pressure and airflow, which are essential for understanding the physics of flight.

Highlights

An aeroplane stays up in the air due to the physics of air pressure.

Air is made up of small molecules, which are in turn made up of tiny atoms.

Air has mass and weight, behaving like a fluid.

Air molecules exert pressure on objects they come in contact with.

Static air pressure is exerted on stationary objects by the air.

An inflated balloon is not squashed because the internal air pressure balances the external static air pressure.

A decrease in external static air pressure causes a balloon to expand.

Dynamic air pressure is caused by an object moving through the air.

The wind resistance felt when sticking your head out of a moving bus is an example of dynamic air pressure.

Total air pressure is the sum of static and dynamic air pressures.

An increase in dynamic air pressure results in a decrease in static air pressure, and vice versa.

Airflow through a tunnel demonstrates the relationship between air speed and pressure.

In a tunnel, a reduction in width increases air speed and dynamic air pressure, while decreasing static air pressure.

The shape of the surface in the tunnel where lower static air pressure occurs is similar to the top surface of an aeroplane wing.

Lift on an aircraft wing is created by reduced air pressure above the wing compared to the higher air pressure below.

As long as the plane moves fast enough, the difference in air pressure generates lift.