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Hello kids, today we're going to talk about what are the effects of thermal energy, ok?

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We are on page 24 and 25. First of all, we need to see that there are four blocks, melting,

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evaporation, expansion and chemical changes, ok? So let's see them one by one and let's read first

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this the top part okay thermal energy first of all we need to know that is the transmission of

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heat okay from one object to another like the other day we were talking about about conduction

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or also it can be convection remember that in which heat energy is transferred from heat to

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liquid okay so let's see this first thermal energy causes changes in the state of some materials so

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So we were talking about effects today. Estamos hablando de los efectos de la energía térmica en objetos o líquidos. ¿Vale? Entonces, ¿qué es? What is thermal energy? ¿Qué causa? It causes changes. Okay? This is important. Changes. All right? Let me change.

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Okay? For example, what changes can thermal energy produce? If you have a look at the first activity, okay, let me see if this works, one moment, okay, look, it says what change of state does each picture show?

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For example, in the first one, the ice cream, you see that it's melting, okay? It's changing from solid to liquid. And in the second one, you see that this is a liquid, could be water, and when it is being transferred thermal energy, it is changed into vapor.

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It is evaporation, ok?

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Es decir, en el helado vemos que se está produciendo un cambio por el calor que está recibiendo

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y ¿qué sucede? Cambia de un sólido a líquido.

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Y este agua o este líquido al recibir calor se está evaporando, está cambiando de líquido a vapor, ¿vale?

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So, let's see the four parts, ok?

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The first one, melting. What is melting? It is what we were talking about, the ice cream, alright? So, look, these are the molecules of an object. For example, what about the ice cube? The molecules are all together. Why? Because it is a solid, ok?

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Then, when it's melting, cuando se derrite, what is happening to the molecules?

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They separate, ok?

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So, melting is a change in state because of thermal energy, ok?

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When a solid receives thermal energy, it changes into a liquid, alright?

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This is called melting, right?

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Then, let's go to evaporation.

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What happens when we transfer thermal energy to a liquid?

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Well, as we were saying before, in this example, we see that this liquid,

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if you pay attention to the molecules, the particles, they are a little bit separated.

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okay when thermal energy is transferred to this liquid then it evaporates okay the particles

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separate more right so let's read when thermal energy is applied to aplica to a liquid it changes

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into a gas this is called evaporation okay this is a process called

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evaporation so after melting and evaporation let's see the two of this

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okay then another effect that can happen when thermal energy is applied is

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transferred when thermal energy is applied we see that there are two other effects in the matter

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we have said that we have melting that is to melt evaporation is worth an effect for example we have

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said the one of the ice cream is worth when you apply heat I repeat a body that is solid it melts

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or can melt and in the case of a liquid it becomes gas each one corresponds to these two

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we see expansion that is expansion is the same as in Spanish it is not to expand when something expands

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Puedes imaginar también, por ejemplo, un cubito de hielo, ¿no?

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So, what happens?

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Thermal energy causes the molecules in a solid liquid or gas to vibrate.

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Okay, what happens?

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When the thermal energy is transferred to an object, okay,

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the molecules vibrate, they start separating. Las moléculas que estaban juntas en un objeto o en

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una materia, tal como hemos visto el helado o el cubito de hielo, cuando es un objeto sólido,

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todas sus moléculas están pegadas. Sin embargo, cuando se aplica calor, se expanden, ¿vale? Sus

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molecules are separated, okay? They vibrate, this is produced, or this produces that they vibrate, okay?

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And as a result, as a result, the material expands. What happens? The ice cream, which used to be a little ball

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that was on the top, well, when it melts, it has expanded, right? It has gone to other

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sides, just like the ice cube, if you put it on a table, for example, when it melts, it

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but media well okay so this expansion for example we also can see that gases

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expand okay also liquid and solids all right then chemical changes was a

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chemical change okay a chemical change is something that is at the beginning

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one material and ends up being another different for example imagine that

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you're going to make a cake okay a pipe that you're going to eat what happens

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what happens with the cake what material or what food do you need for example

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look at this when you make the cake you need eggs flour harina sugar and you

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when you mix it you get a liquid a thick liquid thick es como espeso vale so

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imagine that you're making your cake when you have all the the food mixed

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Cuando ya tenéis toda la comida que necesitáis para hacer vuestra tarta mezclada.

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What are you going to do?

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You're going to put it in the oven.

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Lo ponemos en el horno.

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¿Y el horno qué produce?

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Calor, ¿no?

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It produces heat.

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What happens with this?

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It starts growing and growing and it becomes a cake.

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Se convierte en una tarta, ¿no?

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O en un pastel.

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what used to be an egg or several eggs, flour and sugar, because with it, mixing it, you have

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turned that into a cake. What does this mean? That by applying heat a matter can change.

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You will no longer be able to separate the flour and you will not be able to have the rest of the ingredients

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por separado vale eso es un cambio químico de acuerdo so what does it say it says thermal

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energy can change can cause chemical changes when we cook for example in the oven right en el horno

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and causes permanent changes in the food es decir estos cambios que se producen son permanentes ya

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no podemos volver atrás vale okay so this could be the lesson of today then

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after all this explanation you're going to do the exercise to write so good

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luck and if you have any doubt you tell me bye bye