Heat, Fluids, and Energy Transfer
Thermal and fluid systems
Heat and temperature
Temperature measures how hot or cold something is, while heat is energy transferred because of a temperature difference. Heat flows from hotter objects to cooler ones.
Fluids
A fluid is a material that can flow, including liquids and gases. Engineers study pressure, flow rate, viscosity, and drag when designing pipes, pumps, airplanes, and ships.
Practical examples
A car radiator removes heat. A water pipe must balance pressure and flow. An airplane wing interacts with moving air.
Important fluid terms
What is heat?
Heat is energy moving from hotter to cooler regions.
Correct answer: Energy transferred because of temperature difference
Which of these is a fluid?
Air is a gas, and gases are fluids.
Correct answer: Air
What is pressure?
Pressure describes how concentrated a force is on a surface.
Correct answer: Force per unit area.
Name one engineering system that involves fluids.
Many systems rely on liquid or gas flow.
Correct answer: Any reasonable example such as pipes, pumps, wings, engines, or radiators.