Heat Flashcards
What happens when we heat a solid, liquid or gas?
It expands
What is heat?
It is a form of energy
What happens when we cool a solid, liquid or gas?
It contracts
What are the three methods of heat transfer?
Convection
Conduction
Radiation
What is conduction?
Heat travels from particle to particle along a substance, normally a solid
What is convection?
Heat travels through a fluid (liquid or a gas) when the particles move and carry the heat
What is radiation?
Heat travels from a hot object without the need for a medium, does not need a solid, liquid or gas to go through, will flow through a vacuum
What is a conductor?
Something that allows energy e.g heat to flow through it E.g metal is a good conductor
What is an insulator?
An insulator is a substance that doesn’t allow heat to flow through easily e.g plastic
How do you show that a solid expands when heated and contracts when cooled
Ball and ring apparatus
What is the function of air ?
It is a good insulator, keeps animals warm, is trapped by the fur and helps to insulate animals
How does layers keep us warm?
The hairs on our arms are not very good at keeping us warm if we wear layers of clothes, air is trapped to keep us warm
What is a medium?
A solid, gas or liquid
How do you show the expansion of liquids when heated and contraction when cooled?
Boiled water in a round bottom flask, a glass on top of it, a bunsen burner under the flask and the retort stand to hold the flask
What is the result of the investigation that water expands when heated and contraction when cooled
The expanded water rises up the glass tube but when the bunsen burner is off the water sinks
How do you show the expansion of gases when heated and contraction when cooled
A rounded bottom flask held upside down by the retort stand, a water filled beaker below the flask and a bunsen burner held at the side of the flask
How do you show the transfer of heat energy by conduction in solids.
A boiled water filled basin with different metals sticking out of it and wax at the tip of each metal and a drawing pin at the end of metal
What is the result of the experiment to show the transfer of heat energy by conduction in solids
When the heats travels along the rods and the wax melts dropping the pins this shows that the first rod to drop their pin is the best conductor
How do you show the transfer of heat energy by convection in water
Put a bunsen burner under a tripod and place a water filled beaker above the tripod put some potassium permanganate
What is the result of the transfer of heat by convection in water?
The powder acts as dye with the water it slowly rises and then sinks
What is the conclusion of the transfer of heat energy by convection in water
In the water this shows convection as the dye rises with the water and as it cools at the top it sinks this is convection currents
How do you show the transfer of heat by radiation?
Put two thermometers in two boiling water filled metal cans and place the two cans on a tripod each
What is the result of showing the transfer of heat by radiation
The temperature drops
What is the conclusion of showing the transfer of heat by radiation?
The heat travelled by radiation from the hot water to the cans
Why does the bimetallis strip bend?
It expands because the copper expands more than the iron
What temperature does water has its greatest density
4C
Why does ice float on water?
The volume of the ice will be bigger than the volume of water
What is the melting point of ice?
0C
What is the boiling point of water?
100C
What happens to the boiling point of water when the pressure increases?
It increases the boiling point
What is latent heat?
Change in state not in temperature
In a graph when the line is getting or lower if it stays straight for a while
what does it mean
If it stays straight it means change in state
What does the experiment show about the transfer of heat energy in water
Water is not a good conductor
