Fluid Pressure - Billy's Still Dreaming about Physics

Summary

In this engaging and educational video, Billy explores the concept of fluid pressure by calculating the pressure caused by water in his tadpole tank. The script covers how pressure depends on the fluid's density, gravitational field, and depth, not the fluid's surface area. It also explains the difference between absolute and gauge pressure, touching on the effects of atmospheric pressure and how it impacts fluid systems. The video further explores how amphibians, like tadpoles and frogs, breathe through different mechanisms. Throughout the discussion, the video mixes physics concepts with biology, offering an insightful and fun learning experience.

Takeaways

• 😀 The pressure at the bottom of a fluid tank is determined by the fluid's density, the gravitational field, and the depth of the fluid.
• 😀 The formula for pressure at the bottom of a tank is: pressure = density × gravitational field × depth.
• 😀 The area of the bottom of the tank doesn't affect the pressure caused by the fluid.
• 😀 Fluid pressure increases as the depth of the fluid increases due to the weight of the fluid above pushing down.
• 😀 Atmospheric pressure, caused by the weight of air above us, is approximately 101,000 Pascals at sea level.
• 😀 The total pressure on an object submerged in fluid is the sum of atmospheric pressure and the pressure caused by the fluid.
• 😀 Gauge pressure is the pressure caused by the vertical column of fluid, while absolute pressure is the sum of atmospheric and gauge pressures.
• 😀 The pressure at the bottom of the tadpole tank, including atmospheric pressure, is approximately 103 kilopascals.
• 😀 Atmospheric pressure decreases as you go higher in altitude, such as when flying in an airplane, which causes ear pressure changes.
• 😀 Fluids, including air and water, exert pressure on surfaces by the constant motion and collisions of their particles.
• 😀 Liquids are generally considered incompressible, meaning their volume and density do not change significantly under pressure.

Q & A

What is pressure and how is it related to the water in the tadpole tank?

Pressure is defined as the force exerted per unit area. In the context of the tadpole tank, the pressure at the bottom is caused by the weight of the water above it, and it depends on the water's density, the gravitational field, and the depth of the water.

How do you calculate the area of the bottom of the tadpole tank?

The area of the bottom of the tadpole tank is calculated by multiplying the length (50.2 cm) by the width (25.4 cm), resulting in 1,275 square centimeters. This is then converted into square meters by multiplying by 1 squared meter over 100 squared centimeters, giving 0.1275 square meters.

What formula is used to find the pressure at the bottom of the tank?

The formula for pressure is: Pressure = Force / Area. To calculate the pressure at the bottom of the tank, you first determine the force of gravity acting on the water and divide it by the area of the tank's bottom.

How do you calculate the mass of the water in the tank?

The mass of the water is calculated using the formula: Mass = Density × Volume. The volume of the water is the area of the bottom of the tank multiplied by the depth of the water.

What is the relationship between density, gravity, and pressure?

Pressure caused by a fluid depends on the fluid's density, the gravitational field, and the depth of the fluid. The equation for pressure is: Pressure = Density × Gravitational Field × Depth.

What is the unit of pressure used in the script, and how is it converted?

The unit of pressure used is the pascal (Pa). The pressure at the bottom of the tadpole tank is calculated as 1,793 pascals, which is then converted to kilopascals (kPa) by dividing by 1,000, resulting in 1.79 kPa.

What does 'gauge pressure' refer to?

Gauge pressure refers to the pressure caused by a fluid in a vertical column. It is calculated as the density of the fluid times the acceleration due to gravity times the vertical height of the fluid column.

What is the difference between 'gauge pressure' and 'absolute pressure'?

Gauge pressure is the pressure caused by the fluid itself, whereas absolute pressure is the total pressure, which includes both the gauge pressure and atmospheric pressure.

How does atmospheric pressure affect the total pressure at the bottom of the tank?

The total pressure at the bottom of the tank is the sum of atmospheric pressure and the gauge pressure caused by the water. Atmospheric pressure is approximately 101,000 pascals (1 atm), and the gauge pressure from the water adds to this.

What happens to pressure as you dive deeper into a body of water?

As you dive deeper into water, the pressure increases because the weight of the water above you increases, exerting more force on your body. This is why deeper water creates more pressure.