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Welcome everybody, we are going to talk about natural science, the unit 4, matter.

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What is matter? Matter is everything that surrounds us.

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It's everything made out of atoms.

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And we can find it in different stages.

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we can find it in solid state, liquid state or gaseous state, okay?

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Matter or solid, liquid and gases. So solids, what are the main characteristics

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of solids? Solids hold shape and have fixed volume, it doesn't change the

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volume of the solid liquids the shape they have it's because of the container

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where are they and the volume is fixed it doesn't change the amount of space

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that they use is always the same and gases the shape of the gas is the shape

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of the container and the volume also is the shape of the container so why is that because we have

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everything is made out of atoms so all the matter is formed is formed by atoms and atoms have

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are tiny particles that form matter and they are formed of three different elements. They are

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formed by electron, neutron and protons and because of that, because of the atoms that form the matter,

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we see that the solid all the atoms have a specific order and they doesn't move in liquids

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the atoms can move a little bit in gases the atoms move a lot because there's a lot of space between

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the atoms. So we can classify the matter in two different types of matter. We have

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pure substances and mixtures. Pure substances are made of one type of

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molecule. A molecule is a group of atoms so molecules can be formed by one only

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type of atom that we therefore we call it an elemental pure substance or a

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combination of more than one atom, so we call it compound. Then we have the

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mixtures that are formed by two or more different types of molecules that are

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not chemically combined. And they can be homogeneous or heterogeneous. We're

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going to see what does it mean. Homogeneous mixtures have a consistent

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color and texture. All the compounds, all the substances that form the mixture are

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distributed in a way that we cannot differentiate where does the one atom

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starts and where does the other starts the two compound components of the

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mixture and then we have the heterogeneous mixtures that we can see

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with our eye the different components of the mixture we have one component we

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have another and we can see that they are different for example the milk it's

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an homogeneous mixture why because it is compound by more than one component for

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example in meal we have water proteins we have lipids sugar etc and if we see

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with our eye we cannot differentiate where is the water where are the

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proteins where the lipids where's the sugar everything is the same but on the

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other hand if we see this granite rock run it if we look with the eye we can

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see that they have different components they have quartz they have and other

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minerals that we can see here and here and with our eye we can see the

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different components so it is a heterogeneous mixture so in other words homogeneous mixtures

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have consistent color and texture every part of the mixture has the same properties

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for another example of homogeneous mixture is the air it doesn't depend if we breathe the air here

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or the breath that you're breathing in your room it will have the same elements oxygen nitrogen

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and argon and although also other compounds and heterogeneous mixtures have different texture

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and color. Each substance retains the properties of the beginning. For example,

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concrete is a mixture of cement, water, sand and small stones and pebbles. You

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can see in the picture that here you have the different pebbles in the

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concrete and last but and last but not least we have the solutions what are the

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solution it's a special type of a special type of homogeneous mixture in

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which the one of the parts of the mixture is a liquid and the other

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substances are, could be liquids, could be solids, so those other substances

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are dissolved in the liquid. So we can differentiate between the solvent

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that is the liquid and the solute that usually is the other components that

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usually are solid or gases and then when you stir it up you move it you cannot differentiate

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with the eye the parts the solvent and the solute so we have a homogeneous mixture