heat Flashcards
What are the 3 types of heat transfer
Convection, radiation and conduction
What is convection
Convection is a form of heat transfer that occurs only in gases or liquids. Convection currents form by hot, less dense air rising and cooler, more dense air sinking.
What is radiation
Heat transfer through waves where no contact is required
What is conduction
Heat transfer in solids through contact
Examples of convection
sea breeze and land breeze, boiling water, air inside hot air balloon
Examples of radiation
Warmth from fire, microwave, heat from sun
Examples of conduction
Hot coffee heating outside of mug, ironing clothes, cooking food in a frying pan
What is a conductor
A material that transfers heat easily
What is an insulator
A material that blocks or slows heat transfer
Examples of conductors
Coffee mugs, pots, metal cutlery
Conductor materials
Copper, steel, iron
Examples of insulators
Glass cups, balloons, wood
Insulator materials
Wood, glass, rubber
Heat energy always flows from the object with the ___ temperature
Higher. Heat energy always transfers from the hotter object
Why does a balloon expand when heated
Because when the balloon is heated the particles inside start moving faster which increases pressure. The increased pressure causes the balloon to expand.
What happens to a railroad on a hot day?
Heat causes steel railroad tracks to expand and to buckle under the extra stress. The heat transfer from the sun to the track is radiation.
What happens to a spoon when it is heated over a flame
The heat from the flame is radiation waves. When the spoon is heated it becomes hot. If a spoon was to be touching the flame this would then be conduction.
What causes wind
The difference in temperature. Warm air rises while cool air sinks producing convection currents.
Is hot or cold air more or less dense.
Hot air is less dense so it rises.
Cool air is more dense so it sinks
White or Black
White reflects heat while black absorbs it
