Everyday Science · 55 sec
Pressure Changes the Boiling Point
Water does not always boil at the same temperature.
The useful idea
- Understand
Boiling begins when a liquid's vapor pressure matches the pressure around it.
- Connect
Lower atmospheric pressure at high altitude lets water boil at a lower temperature.
- Apply
A pressure cooker raises the surrounding pressure, allowing liquid water and food to reach a higher temperature.
Why this matters
Cooking time changes when pressure changes the temperature at which boiling occurs.
Try this
Ask whether a process depends on temperature alone or also on pressure.
Test your recall
Which action best applies “Pressure Changes the Boiling Point”?
- For plans several days away, watch the probability and range of outcomes rather than one icon.
- Check every tire cold each month and use the vehicle-maker's door-label pressure rather than the sidewall maximum.
- Ask whether a process depends on temperature alone or also on pressure. — correct
Cooking time changes when pressure changes the temperature at which boiling occurs.