Heat and Energy
Everyone probably knows something about heat . We often use the word to describe something that feels hot when we touch it or to describe a hot day. To fully understand what heat is, we first have to understand something about energy.
Energy has to do with the movement of the particles that make up matter. If we were to look up close at the particles of something very cold, we would see them moving very slow. If their movement is very slow, they have less energy than the particles that make up something that is hot.
Heat is actually a form of energy that is being transferred from a substance at a higher temperature to another substance or substances at a lower temperature. Have you ever touched a hot pot that was on a stove? What happens when you touch it? It burns your hand because the heat energy is transferring from the hot pot to your hand. Your hand had a different temperature than the hot pod and your hand was much cooler than the hot pot.
Heat energy always travels from a hotter substance to the colder substance. In this case it travels from the pot to your hand. Think about what happens to a mug when you pour hot water into it. It felt cool at first but then felt hotter as you pour the hot water. The hot water transferred its heat energy to the mug which was cooler.
Heat is not the same as temperature. Have you ever used a thermometer to measure some things temperature? Temperature is a measure of the energy that matter contains or how hot or cold it is. So when you use a thermometer you are measuring how fast or slow the particles in matter are moving. The faster the movement of the particles in an object, the higher the temperature of the object will be.
Heat once again is the transfer of an object energy to another object with a lower temperature. Heat energy is something that is very useful to all living things. In fact no life would be possible on our planet without the light and heat energy from the sun. The sun makes it possible for all plants to grow. Plants in turn are needed by living things to consume when we’re in our homes or schools we use heaters. These heaters heat the air right above them and eventually transfer this heat energy to the rest of the air in the room. This works in a way quite similar to how an oven transfers its heat to a bowl of liquid kept in it the hot bowl transfers its heat energy to the liquid being heated . Toasters and coffee makers are two other sources of heat energy found in our homes. Can you think of any other source of heat energy?
A fire of any kind is a source of heat energy. If you go camping a fire will provide a nice source of heat energy on a cold night. A gas stove has flame that is the source of heat for warming things up.
(note : don’t try this at home)
Our own bodies produce heat. You can tell this by holding a piece of ice after a few minutes the heat energy from your body is transferred to the ice causing it to melt. A bathtub that is filled with hot water can transfer its heat energy to a person who needs to be warmed up.
Heat energy can be used for many things. The most obvious is for keeping us warm in our homes and cooking food on our stove. As mentioned before a hot bath can be used to warm up our bodies. Heat energy is also used by plants to make food for themselves.
In some places there are hot sources of water found deep within the earth. These can be used as a source of electricity. When hot water is used to make electricity, this is called geothermal energy.
A temperature is an objective comparative measurement of hot or cold. It is measured by a thermometer. Several scales and units exist for measuring temperature, the most common being Celsius (denoted °C; formerly called centigrade), Fahrenheit (denoted °F), and, especially in science, Kelvin (denoted K).