"Magical Lift" Buoyancy and Lift PPT Courseware 2

"Magical Lift" Buoyancy and Lift PPT Courseware 2

1. The relationship between fluid pressure and flow rate

Water, air, etc. are fluid and are collectively called fluids. When fluid moves, it will show a wonderful characteristic in places with different flow speeds.

1. Fluid:

Both liquids and gases are fluid and are collectively called fluids.

2. Fluid pressure:

The pressure at which a fluid flows is called fluid pressure.

3. Flow rate:

The speed at which a fluid moves is called flow velocity.

Activity 1 Wonderful experiment

A. Stubborn piece of paper

Blow air between two pieces of drooping paper. What do you observe?

The two pieces of paper move closer to the middle

Reason: The air flow speed inside and outside the paper is different when blowing

The paper will float upwards

Reason: When blowing, the air flow speeds on the paper and down are different.

What thoughts can you draw from these two phenomena?

B. Disobedient table tennis

As shown in the picture, first hold the ping pong ball with your hand, and then blow air into the glass funnel. If you release your hand at this time, will the ping pong ball fall?

The table tennis ball will not fall

Reason: The airflow speeds above and below the table tennis ball are different

C. Make a simple sprayer

As shown in the picture, make a plastic straw at a right angle, make a hole in the bend, insert it into the water, and blow air in from the mouth of the water pipe. What phenomenon do you observe?

From the above three experimental phenomena, we can summarize the relationship between fluid pressure and flow rate:

Where the flow velocity is high, the pressure is low;

Where the flow velocity is small, the pressure is strong.

I can do it

1. One of the reasons why the smoke from rural stoves is discharged out of the house along the chimney is that the wind blows over the top of the chimney, causing the air flow speed and pressure there to be _______, so the smoke is discharged out of the house along the chimney.

2. The essence of a tornado is a high-speed rotating air flow. It can "suck" objects or people and animals on the ground into the air. Tornadoes can "suck up" objects because ( )

A. The pressure inside the tornado is less than the pressure outside

B. Tornadoes increase the buoyancy of air on objects

C. Tornadoes cause objects to experience less gravity

D. The pressure inside a tornado is greater than the pressure outside

3. When a car drives quickly across the road, the leaves falling on the road will ( )

A. Flying from the roadside to the car

B. Flying from the road to the road

C. Flying upward

D. Not affected

2. How lift is generated?

Activity 2 Understanding lift

As shown in the picture, take an airplane wing model and mount it on the stand, and place the electric fan directly in front of the wing model. What do you see when the electric fan is powered on?

Causes of lift:

The pressure difference between the upper and lower parts of the wing creates upward lift

The air flow speeds above and below the wing are different, and the airflow speed above the wing is greater than the flow speed below. According to the relationship between fluid pressure and flow velocity: the pressure difference between its upper and lower parts creates an upward lift force on the aircraft.

I can do it

1. Have you ever had this experience: walking in the rain with an umbrella, as shown in the picture, when a strong wind blows, the umbrella surface may be "sucked" and severely deformed. Regarding this phenomenon and its explanation, which one of the following is correct ( )

A. The umbrella surface is "sucked" downwards

B. The air velocity above the umbrella is greater than below

C. The air velocity above the umbrella is equal to the velocity below

D. The air velocity above the umbrella is slower than below

2. Some sports cars are equipped with an "airflow deflector" at the rear of the car. As shown in the figure, since the upper surface of the "airflow deflector" is flat and the lower surface is arc-shaped and convex, when the sports car is traveling at high speed, the airflow deflector will The speed of the air above it is ___ (optional "larger or smaller") than the speed of the air below it. At this time, the air pressure above is __ (optional "larger or smaller") than the air pressure below. In this way, "airflow deflection" "The device" is subject to a pressure difference toward ____ (optional "up or down"), thereby causing the wheels to grip the ground

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"Magical Lift" Buoyancy and Lift PPT courseware:

"Magic Lift" Buoyancy and Lift PPT courseware 1. Fluid and flow rate Fluid: Liquid objects are called fluids, such as water and air. When a fluid flows, what characteristics will appear in places with different flow rates? A. The stubborn piece of paper moved toward the two drooping papers...