hi there welcome to mr. Lee Han teaches you stuff this is grade 9 chemistry lesson 1 matter and the particle Theory so first thing we want to look at is what is matter and matters anything that contains both mass and volume so we might as well define those as well mass is how much matter is in an object we measure mass in grams kilograms milligrams stuff like that it's very important that we don't get mass confused with weight so you may weigh a hundred pounds and when you go into space let's say you don't weight hundred pounds you're floating around weightless but you're not floating around massless you still are made up of the same amount of matter similarly if you step on a scale on the moon it'll say that you weigh less right because you're not pushing down as hard on that scale because gravity's not as hard or not as strong but you will not have less mass you'll have the same amount of mass volume is how much space something takes up we measure volume in liters and milliliters etc so the three states of matter are solid like this rock liquid like a glass of water and gas like the gas inside this balloon or possibly the gas in the air that that balloon is floating through there are several changes in state so melting is when something goes from a solid to a liquid so there's an example some ice cubes melting freezing is when a liquid turns into a solid like this water that I left in the freezer and it's important to note that the melting point is the same as the freezing point so for water for example that's zero degrees Celsius so the same temperature at which something melts is the same one at which it will start to freeze evaporation is when something goes from a liquid to a gas so when you've got water boiling on the stove some of that water will evaporate condensation it's when something goes from a gas to a liquid if you ever get a cold pop for example out of the fridge you might notice that this condensation around it now for two that you may not have heard of sublimation and deposition sublimation is when something goes from a solid to a gas so an example of that would be dry ice which is basically solid carbon dioxide it changes directly into a gas i'm deposition gas to a solid this is more common than you might think that's what frost is so if you ever see frost on a pine branch like this or frost on a window that is solid water that has just come out of the air it went directly from gaseous water to solid water now how does this all relate to the part of the particle theory was created to describe the structure and behavior of matter and there's five main points to the particle theory so we'll take a look at those first point is that all matter is made up of tiny particles and all of those particles have spaces in between them so there's a little bit of room between each one of those particles point number three all particles of one pure substance are the same different substances are made of different particles so if we've got two substances here they're both pure substances they're all made of the same type of particle but since they're different types of substances they have different types of particles making up one in this case is green and one is blue number four the particles are always moving the more energy the particles have the faster they move so even for a solid object so the computer you're watching on this on your hand your desk all the particles that make up that desk or hand or computer are moving a little bit to the extent or the extent to which they move around determines whether a solid liquid or a gas but they're all moving a little bit and there are attractive forces between the particles these forces are stronger when the particles are closer together so the three particles here are fairly close together they're very attracted to each other whereas this one off by itself at the bottom is not as attracted to the other ones so how does the particle Theory relate to the states of matter as energy is added to particles they move around more this causes the bonds between the particles to weaken so here we have some very low energy particles this is a solid now if this solid is an absolute zero then it's not going to be moving around at all but as we add a little bit of energy to it a little bit of heat those particles will start to jiggle around more so it's still a solid no one none of the particles have moving past each other but though they'll kind of shake in place now when you add even more energy the particles get so much energy that they move past each other so if they can slide past each other and move around that substance is now a liquid then as you add even more energy the particles are no longer bonded to each other so they're flying around randomly the substance is now at gas these are very high-energy particles you can tell by the looks on their faces now evaporation is when something turns from a liquid to a gas and that happens at 100 degrees Celsius but you may think well why is it that puddles disappear puddles evaporate but it's not 100 degrees out and the reason why is because when those particles are just randomly moving around in the puddle and some of them will be close to the air and some of them have randomly just enough energy to pop up into the air and start floating around and be a gas so although the temperature of the puddle is determined by the average temperature of all the particles some particles have more energy than others and if those particles are found at the top of the puddle right next to the air they may have enough energy to sort of does it sort of bounce off the puddle and disappear into the air so that's why puddles evaporate if you were wondering all right so that's it for this video tune in to the next video which will be mixtures and pure substances