The transfer of heat from one substance to another by direct contact is called conduction or diffusion.
The American astronomer Edwin Hubble made the observations in 1925 and was the first to prove that the universe is expanding. He proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. This is now known as Hubble's Law.
Metals that conduct heat allow free electrons to roam around, which vibrate and conduct energy, while heat insulators do the opposite.
Convection is the transfer of heat through liquids or gases. Example: When cold air enters your home, it mixes with warm air. Heat energy is transferred to the cooler air, and the overall temperature of the room is lowered. Result: More energy is required to replace the heat transferred to the cooler air.