Termodinamika - Tekanan dan Jenis-jenis tekanan

Summary

In this educational lecture, the instructor introduces the fundamental concepts of thermodynamics, focusing on pressure. The definition of pressure as force per unit area is explained alongside four main types: atmospheric, absolute, gauge, and vacuum pressure. The lecture highlights the importance of measuring pressure using barometers and manometers, referencing the historical contributions of Evangelista Torricelli. Through clear explanations and practical examples, students are encouraged to grasp the critical principles of pressure, setting a foundation for further exploration in thermodynamics.

Takeaways

• 😀 Introduction to thermodynamics focuses on understanding pressure.
• 💡 Pressure is defined as force per unit area, represented by the formula P = F/A.
• 📏 The unit of pressure is Newtons per square meter (N/m²) or Pascals (Pa).
• 🌍 Atmospheric pressure is the pressure exerted by the atmosphere and is measured as 760 mm Hg at sea level.
• 🔬 A barometer is used to measure atmospheric pressure, using mercury to show the height of the liquid column.
• 📈 Historical context: Evangelista Torricelli invented the mercury barometer in the 17th century.
• 💨 Different types of pressure include atmospheric pressure, absolute pressure, gauge pressure, and vacuum pressure.
• 🔍 Absolute pressure refers to the actual pressure of a gas, such as LPG in a gas cylinder.
• ⚖️ Gauge pressure is the difference between the pressure of a fluid and the atmospheric pressure.
• 🔄 Vacuum pressure is when the pressure of a gas is lower than atmospheric pressure, causing mercury to rise in the barometer.

Q & A

What is the definition of pressure according to the lecture?

Pressure is defined as force per unit area, expressed mathematically as P = F/A, where F is the force applied and A is the area over which it is applied.

What are the units used to measure pressure?

Pressure is measured in Newtons per square meter (N/m²), which is also referred to as Pascals (Pa).

What are the four types of pressure mentioned in the lecture?

The four types of pressure are atmospheric pressure, absolute pressure, gauge pressure, and vacuum pressure.

How is atmospheric pressure defined in the transcript?

Atmospheric pressure is defined as the pressure exerted by the weight of the atmosphere, equivalent to 760 mm Hg at 0°C, or 1.013 bar.

What is absolute pressure, and how is it measured?

Absolute pressure refers to the actual pressure of a gas, measured using instruments like manometers, independent of atmospheric pressure.

What is gauge pressure, and how is it calculated?

Gauge pressure is the pressure relative to atmospheric pressure, calculated as the difference between absolute pressure and atmospheric pressure.

What does vacuum pressure indicate?

Vacuum pressure indicates a pressure lower than atmospheric pressure, often demonstrated by the movement of mercury in a barometer.

Who invented the mercury barometer, and when?

The mercury barometer was invented by Evangelista Torricelli in the early 17th century, specifically between 1608 and 1647.

What is the relationship between atmospheric pressure and mercury height in a barometer?

Atmospheric pressure balances the weight of mercury in a barometer, which rises to a height of 760 mm when measured at standard conditions.

What practical application of pressure measurement is mentioned in the lecture?

One practical application discussed is measuring the pressure of gases in LPG cylinders using pressure regulators and gauges.