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Good morning guys, I'm going to tell you what you have to do today for Natural Sciences.

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So, as usual, everybody please click on Mi Clase, then we go to Content,

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and then we click on Natural Sciences. We continue on Unit 5 about Forces,

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and what we are going to see today it is a force called Abthrust. Abthrust.

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all right, which is a new force that you didn't know yet, okay, so what is upthrust?

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upthrust is a contact force applied by water and air, okay, and it pushes up the objects,

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okay, in these two means, all right, upthrust is opposite than gravity, okay,

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gravity pulls us down and up thrust pushes us up, all right? So if we have seen that the gravity

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was a non-contact force and it was a pull force, up thrust is completely opposite, all right? It's

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a contact force and it's a push force all right

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so um while athras pushes up

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this this man which is parachuting the gravity which

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pushes him down all right because of this force a bird can fly

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a boat can float, you can swim, and a feather falls slowly.

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Well, it's not only because of up thrust, there is also friction acting on it,

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but you will see that in a very famous experiment. I'm going to include a video for next day,

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okay, in next session, and I hope you like it, okay, but it is kind of explaining

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how some objects they fell down, okay? So the mass and volume of an object influence the amount of

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upthrust, okay? So a very small mass has more upthrust, okay? A big volume with the same mass

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means more upthrust, okay? So a feather with a very low mass, a very big volume, will float

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in water and will fall very slowly, but remember about the experiment, okay? It's not only upthrust,

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okay? Whilst one object with a large mass but small volume has less upthrust, this

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is the example of the feather that is bigger in volume and with lower mass and

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it will have a bigger force of upthrust while the coin will have less which is

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smaller in volume but bigger in mass okay so this is why the feather floats

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and falls very slowly okay and this is why the coin falls very fast and sinks

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in water pay attention to this word sinks in water all right

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Archimedes an ancient ancient Greek discovered upthrust during one of his

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bath over 2,000 years ago okay because he filled up the bath the bathtub okay the

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bathtub and he was observing what would float then he went in the bath and many

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of the water that was in went out okay so he discovered that while he was in

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In the water, there was a force that put the water up and that the water that an object

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displaces has an upward force, ok?

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I'm going to explain all this in Spanish.

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Well, I was saying that the upthrust is a force of vertical push, okay?

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It is a force of push upwards.

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I think there is no word in Spanish to explain it in one word, okay?

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But it is a force of vertical push.

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Well, we had seen that gravity was a force of no contact and grip.

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Well, this is the opposite.

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this is a force of contact and in addition to the push that objects have in the air and in the

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water, as we can see with this parachute, gravity pulls it down

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while the upthrust, this vertical push force, avoids the force of gravity a little,

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of agreement, that is, we can see that the gravity and the upthrust are opposite forces,

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one goes down and the other up, because of this force, the birds can fly,

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the boats float, we can swim and a feather falls slowly, although well, it is not only the upthrust

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lo que hace que esta pluma caiga despacio hay otra fuerza como por ejemplo la fuerza de fricción o de

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rozamiento os voy a poner un vídeo para la próxima sesión sobre un experimento muy famoso sobre la

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caída de objetos a ver qué os parece espero que os guste bueno estaba diciendo también en inglés

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que tanto la masa como el volumen de un objeto que influyen en su fuerza de empuje ok o sea que

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un objeto con una masa pequeña y con un volumen grande tendrá mucha fuerza de empuje vale esto es

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lo que hace que una pluma pues caiga despacio pero flote también en el agua vale o sea que

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estamos hablando de masa pequeña pero también volumen grande por ejemplo para que un paracaídas

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a parachute floats the fabric of a parachute because it is quite it is quite heavy agree

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but being very to have a very large volume and unfold very widely because then it makes this

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up thrust work better agree that is, it is both the mass and the volume of an object

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And on the contrary, an object that has a larger mass and a smaller volume will have much less force of this push, and that is why here we can see that the feather has more volume, it is larger and has less mass, that is, it weighs less, and that is why its upthrust is greater.

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y una moneda tiene más masa y es más pequeña tiene menos volumen por tanto tiene menos afras y por eso

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y por eso cae más rápido y además sing sin votar sings es hundirse hacia el fondo de acuerdo bueno

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arquímedes tenemos aquí que era un científico griego de la edad antigua y que descubrió esta

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force of push of agreement well he discovered

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quite a few laws but this is the famous one in which he said the famous

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eureka word of agreement that it was that well nothing he discovered filling his

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bathtub that when he got into the water there was a

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amount of water that was coming out of the bathtub then he realized that

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the water that is displaced by an object that gets into the water experiences a force upwards

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of agreement, that is, while this little man this Archimedes when he got into it threw towards he exercised a force

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downwards the water that surrounded him exercised a force upwards and that is why he got out of the

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bañera. Ok, next page, buoyancy. Buoyancy is the ability of an object to float in a liquid. Look at

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Archimedes' notes. We are not writing these sentences in your notebook, but just pay attention

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on it, ok? Buoyancy es como la flotabilidad, ¿de acuerdo? De un objeto en un líquido, es la

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flotabilidad, okay? Why a rubber duck floats and a metal duck sinks? Obviously, because of the weight,

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okay? So, if the mass of this duck, rubber duck, is 0.1 kilograms, his weight would be times 10,

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that's it, you remember that, so it would be 1 newton, 1 newton down, okay, and if this is 3

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kilograms, to calculate the weight, we would times 10, so it would be 30 newtons, okay, so we have

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1 newton down and 30 newtons down all right so obviously being the weight bigger it would be

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unbalanced okay so with smaller weight balanced forces because weight is the same as up thrust

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so then this rubber duck would float, ok?

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And if the weight is bigger than upthrust, it will sink and there would be unbalanced forces, ok?

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Decía que esta es la flotabilidad de los objetos, ¿de acuerdo?

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¿Cómo calcularlo?

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¿Por qué un pato de goma flota y un pato de metal no?

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bueno pues estábamos diciendo que si esto pesaba 0,1 kilogramos para calcular

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el peso teníamos que multiplicar por 10 eso es que lo estabais pensando algunos

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que lo vimos la semana pasada entonces 0,1 por 10 es un newton tenemos aquí

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este este ejercería una fuerza de un newton y este sin embargo tres

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kilograms we would multiply it by 10 to find out the weight and it would be 30

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newtons 30 newtons this one newton and this 30 newtons because look at the

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first case the weight is equal to the force of

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push are balanced forces and therefore being equal this force and this

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force the duck floats but in the second case the weight is greater than the

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fuerza de empuje. Son fuerzas desequilibradas y, por tanto, el pato se hunde.

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Ok, so what do we have to do now? We are going to do the digital activities in the

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plazón for today they are activities seven read and match and eight all right seven and eight

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classify the words all right what sinks and what floats que es lo que se hunde y que es lo que

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flota. All right? This is for the next week. Y acordaos que os pondré el vídeo del experimento

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para que lo veáis el próximo día y además tendréis que hacer una live worksheet. All right?

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Bueno, esto ha sido todo. Hasta luego. Bye, bye.