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Heat and Light (I)
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Hello everyone, this is Cori. I hope you are doing well. Today I am going to be talking
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with you about heat and light. Heat is a form of energy that passes from a hotter object
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to a colder one. For example, the sun is a hotter object than the earth. The sun
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passes energy to the earth. An object gets warmer when it absorbs heat and gets cooler
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when it gives off heat. So when we heat something up on the stove, let's say we heat a pan on the
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stove, the pan gets warmer. The pan will take in heat. It will absorb heat from the stove
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and the stove will get somewhat cooler as it gives off heat to the pan.
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So an object gets warmer as it takes in heat
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and the object that is giving off heat gets cooler as it loses heat and sends it off.
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A source of heat is anything that produces heat.
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There are natural sources of heat.
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These are sources that are caused by nature.
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For example, the sun or lava from a volcano.
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We also have artificial sources of heat.
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These are things that are made by humans.
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For example, heaters or radiators are artificial sources of heat.
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Many of us have a heater or radiator in our home to keep us warm.
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At school, we have heaters as well in every classroom.
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Light bulbs are also artificial sources of heat.
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And wood fires are artificial sources of heat.
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Temperature is the measure of how hot or cold something is.
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We measure this, we measure temperature, using a thermometer.
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Thermometers can be analog.
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With analog thermometers, we read the temperature on a scale.
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Thermometers can also be digital. With digital thermometers we read the temperature on a screen.
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Here you can see an analog and a digital thermometer. Over here we've got the analog
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thermometers. To figure out how hot or cold it is we have to look at our scale. We'll follow
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this red line all the way up and we can see that the temperature is 21 degrees
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Celsius. Now over here we have our digital thermometers. To figure out the
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temperature on a digital thermometer we just have to look at the screen. On this
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screen we see that the temperature is 31.2 degrees Celsius. Heat can be
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transferred by conduction, convection, or radiation. Conduction is when two
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objects are in contact, they are touching, and when these objects are in contact
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heat is transferred from one object to the other. The temperature of the colder
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object increases, the temperature of the colder object goes up, gets warmer, and
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the hotter object gets colder. That means the temperature of the hotter object
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goes down. We can see conduction when we touch a hot stove. The temperature of
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your hand will increase. Your hand is colder than the stove. When you touch a
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hot stove, your hand becomes hot and you'll probably get a burn. That is an
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example of conduction. Energy is transferred by direct contact. Next we
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have convection. With convection thermal energy travels through a gas or through
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a liquid. There is a circular movement as the hotter molecules rise up and colder
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molecules move down. You can see this circular movement in our picture. As we heat water up,
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the thermal energy travels through the liquid in a circular movement.
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Next we have radiation. Thermal energy can be transferred through space by electromagnetic
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waves. An example of this is when thermal energy from the sun is transferred to the earth.
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Here we can see the sun is keeping these people warm at the beach. It makes the sand warm and the
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water warm because the thermal energy moves through a lot of space to get to the earth.
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Alright, now I hope you continue to work hard and take care of yourselves.
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Goodbye for now!
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- Autor/es:
- IDOYA PÉREZ MARTÍN
- Subido por:
- Cp castilla alcobendas
- Licencia:
- Reconocimiento - No comercial - Compartir igual
- Visualizaciones:
- 147
- Fecha:
- 15 de abril de 2020 - 9:21
- Visibilidad:
- Público
- Centro:
- CP INF-PRI CASTILLA
- Duración:
- 07′ 23″
- Relación de aspecto:
- 1.23:1
- Resolución:
- 1280x1040 píxeles
- Tamaño:
- 358.99 MBytes