3 methods of heat transfer

A candle burning - you feel the heat from the side. Convection, conduction or radiation?

Radiation - the fire gives off electromagnetic waves of energy.

You get too hot sitting next to a campfire and move away to cool off - convection, conduction, or radiation?

Radiation - the fire gives off electromagnetic waves of energy.

Getting a sunburn - convection, conduction or radiation?

Radiation - the sun sends electromagnetic waves through space.

If you place an ice cube in your hand, describe the movement of thermal energy. How long will the energy continue to transfer?

The thermal energy will move from your hand to the ice cube. It will continue until the ice cube and hand are at the same temperature.

A candle burning - you stick a metal stick with a marshmallow to roast it. Your hand gets burned after leaving it in too long. Convection, conduction, or radiation?

Conduction - since the metal is touching your hand.

Cooking popcorn on a stove using a pot - convection, conduction or radiation?

Conduction - the pan touches the stove, and the popcorn touches the pan.

Burning your hand by touching a hot stove - convection, conduction or radiation?

Conduction - touching is the key.

Direction of heat transfer - is it from hot objects to cold objects, or cold to hot?

Heat always moves from hot objects to cold objects.

Radiation

Heat movement by electromagnetic waves. These waves can move long distances - even through space. This does not involve movement of matter.

Convection

Heat moves as fluids (liquids or gases) get hot and rise. They rise since hot objects are less dense. After they rise, they cool off, become more dense and sink. This process happens over and over - the fluid goes up and down, over and over (in a circular motion).

Conduction

Heat moves from the hotter object to the colder object by direct contact.

Hot molten rock in the Earth gets hot and rises toward the surface, then cools and sinks back down again. Is this convection, conduction or radiation?

Convection - hot rock rising, then cooling off and sinking happens over and over.

A candle burning - you put your hand above the it and feel the heat. Convection, conduction or radiation?

Convection - the heat from the candle warms the air which rises (since it's less dense).

A lava lamp - convection, conduction or radiation?

Convection - the hot "blob" of wax gets hot when it's at the bottom (since it's near the hot light). So it's less dense and rises up, then it cools (since it's away from the heat) and sinks back down again. This happens over and over.

A hot air balloon floating in the air - convection, conduction or radiation?

Convection - the hot air is less dense so it rises.

You place a hot spoon (at 100 degrees C) into a container of ice water (at 5 degrees C). What will happen?

The heat will transfer from the spoon to the ice water. The transfer will keep happening until they are the same temperature (thermal equilibrium) - which will be somewhere in between the starting temperatures (higher than 5 degrees but less than 100).