Heat, temperature, energy transfer, and thermodynamic principles. Specific energy-source technologies belong in Renewable Energy.
Test your knowledge with these top questions!
Why preheat a vacuum flask with hot water before filling it with hot coffee?
A cool inner wall absorbs some of the coffee's heat, so preheating leaves more heat in the drink.
Which scientist designed the double-walled vacuum flask for low-temperature research?
Dewar kept liquefied gases cold in his laboratory flask before manufacturers adapted the idea for everyday drinks.
Which type of heat transfer does a vacuum flask's shiny inner coating mainly reduce?
Heat can cross a vacuum as infrared waves, so the reflective coating handles a kind of heat loss the empty gap cannot stop.
What is removed from the gap between the two walls of a vacuum flask?
With very few gas particles between the walls, heat has little material to travel through by conduction or convection.
Which process spreads heat by circulating water in a pot?
Water near the hot bottom rises as cooler water sinks, helping spread heat through the pot before boiling.
At constant pressure, extra heat added to boiling pure water mainly does what?
The added energy separates water molecules into gas instead of making the boiling liquid hotter.
Why do many stainless-steel pans have a layer of aluminum in the base?
The aluminum carries heat sideways through the base, reducing the hot spots that plain stainless steel can leave.
Metal and wood are both at room temperature. What mainly makes metal feel colder against bare skin?
When both are hotter than your skin, metal can feel hotter than wood because heat then moves into your hand.
At normal air pressure, pure ice melts at what temperature on the Celsius scale?
Extra pressure can lower ice's melting point because liquid water takes up less space than ice.
Which saucepan-handle material conducts heat most slowly?
Wooden handles can still become hot if heat has enough time to pass through the wood.