Pressure Cooking: How Does It Get Hotter Than 15 psi?

In summary, the conversation discusses the concept of pressure and how a pressure cooker is able to raise the boiling point of water. The question is raised as to why a pressure cooker can achieve a higher temperature when the pressure is the same as the natural surroundings. However, it is later discovered that the pressure in a pressure cooker is actually 1 atm above normal atmospheric pressure, allowing for a higher boiling point. The conversation also touches on the difference between a critical thinker and a sloppy thinker.
  • #1
aclark609
35
1
Okay so if 1 atm is the pressure in our natural surroundings (I know it depends on altitude, but humor me, ummkay?), and 1 atm = 15 psi, then why does a pressure cooker get water to boil at 121 degrees Celsius. I mean the pressures are the same. How does a pressure cooker allow it to get hotter?
 
Physics news on Phys.org
  • #2
Nevermind. I just found out it's 1 atm above normal atmospheric pressure. Place palm to face emoticon here. Sorry.
 
  • #3
A critical thinker continuously poses their own good questions, then answers them.

A sloppy thinker is unable to post a clear question and so must wait for another to work out what the question should have been, when the answer becomes immediately obvious.

aclark609; Congratulations on your critical thinking, you will go far.

Susan Sontag said:
"The best answer is one that destroys the question."
 
  • #4
Thank You! I did not expect to get acclaimed for this lol.
 
  • #5


Great question! The key to understanding how a pressure cooker can reach temperatures higher than 15 psi lies in the concept of boiling point elevation. When a liquid is heated, its molecules gain energy and start to move faster, eventually overcoming the attractive forces between them and escaping into the gas phase. This process is known as boiling.

However, when a liquid is under pressure, the increased pressure pushes down on the liquid molecules, making it harder for them to escape into the gas phase. As a result, the boiling point of the liquid increases. This means that in a pressure cooker, the water inside can reach a higher temperature before it starts to boil.

In fact, for every additional 1 psi of pressure, the boiling point of water increases by about 0.5 degrees Celsius. So, at a pressure of 15 psi, the boiling point of water is raised by approximately 7.5 degrees Celsius, allowing it to reach a temperature of 121 degrees Celsius before boiling.

In summary, the increased pressure inside a pressure cooker raises the boiling point of water, allowing it to reach higher temperatures and cook food faster. This is why pressure cooking is a popular method for preparing meals quickly and efficiently.
 

1. What is pressure cooking and how does it work?

Pressure cooking is a cooking technique that uses high pressure to cook food faster. The pot is sealed with a lid, creating an airtight environment, and the pressure created by the steam inside the pot raises the boiling point of water, allowing food to cook at a higher temperature.

2. How does a pressure cooker reach a pressure higher than 15 psi?

A pressure cooker is designed to reach a pressure higher than 15 psi through the use of a weighted pressure regulator or a spring-loaded pressure valve. These mechanisms allow steam to escape and maintain a constant pressure inside the pot.

3. Is it safe to cook at pressures higher than 15 psi?

Yes, pressure cookers are designed and tested to safely cook at pressures higher than 15 psi. They are equipped with safety features to prevent pressure from building up to dangerous levels and causing the pot to explode. It is important to follow the manufacturer's instructions and never attempt to open the pressure cooker while it is still pressurized.

4. How does cooking at higher pressure affect the food?

Cooking at higher pressure allows food to cook faster and retain more of its nutrients. The higher temperature also breaks down tough fibers in food, resulting in tender and flavorful dishes. However, it is important to carefully monitor cooking times and release pressure appropriately to prevent overcooking or burning food.

5. Can any type of food be cooked in a pressure cooker?

Most types of food can be cooked in a pressure cooker, including meat, vegetables, grains, and even desserts. However, delicate foods such as fish and fruits may not hold up well under the high pressure and should be cooked using other methods. It is important to consult a recipe and adjust cooking times accordingly when using a pressure cooker.

Similar threads

  • Mechanics
Replies
4
Views
907
Replies
2
Views
6K
  • Biology and Chemistry Homework Help
Replies
2
Views
3K
  • Mechanics
Replies
2
Views
4K
  • Mechanical Engineering
Replies
3
Views
895
Replies
4
Views
3K
  • Introductory Physics Homework Help
Replies
2
Views
1K
Replies
2
Views
3K
Replies
4
Views
1K
Replies
1
Views
2K
Back
Top