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♨️ What is heat

Heat is atoms in motion.

Why? Because when we raise the temperature of a body, we increase the energy of its atoms. Atoms transmit this energy to each other. We know that atoms are always in motion. Even at temperatures close to absolute zero there is some movement between the atoms.



Have you ever wondered why, in the summer when we step barefoot on the sand it burns our feet? Yes correct! Because the sand became very hot from the sun, which has increased the energy of its atoms. When we step on the hot sand, the atoms of the sand transfer their energy to the atoms of our feet.


The heat is always, absolutely always, moving in the direction from warmer to colder. Cold bodies never transmit heat.

Heat moves:

  • from the Sun to the Earth,
  • from the hot sand to our colder feet,
  • from the hot cup of tea to the hand holding the cup,
  • from the hob to the milk pot, on it …

Have you ever wondered why we dress thicker in winter? Why do we seal the joints under the doors in winter? Yes, to prevent the heat from leaving our body or leaving our home.

What if we put a cup full of hot tea near an ice cube? The heat from the tea will be transferred to the air, from the air to the ice cube. In time, everything in the room will be at the same temperature – the tea, the cup, the ice cube that has already melted, the remaining water on the table, etc.

Whenever there are two bodies with different temperatures, heat always transfer between them. From the warmer to the cooler one.

Take a piece of chocolate in your hand and hold it like that for a while. What is happening? After a few minutes, the piece of chocolate begins to melt and turns into a sticky paste. Why? Because our hand is warmer than a piece of chocolate and the heat from it turns into chocolate.

Do you know that there is no such thing as a cold? And cold bodies do never transmit heat. Why? Because when bodies cool down, they don’t actually take in cold, they lose heat.

What are heat sources and heat receivers?

There is a source and a receiver in every heat transfer process. The warmer body is called the heat source, and the colder body (the one that receives heat from the warmer one) is called the heat receiver. Examples:
Source – the sun
Receiver – the sand on the beach, which is heated by the sun

Source – hotplate on
Receiver – the pan in which we fry the eggs on the stove

Source – our hand holding a piece of chocolate
Receiver – the piece of chocolate we hold

Do you know that heat can also travel, like us? Yes, it can, but it uses other ways of moving, called thermal radiation, convection, thermal conductivity.

👀 Magic heat properties >>>