smile and learn hello friends today i'm studying pure substances and mixtures i have an exam next week and i need to work hard have you ever heard about pure substances and mixtures let's begin we divide substances into pure substances and mixtures it's important to know how to tell one from another let's look at pure substances first your substances pure substances are composed of one single type of matter or element that have specific properties for example water and diamonds are pure substances in a physical change the composition of these substances wouldn't be altered look at this glass of water if i place it in the freezer the water will turn into ice because of the very low temperature but if i took the glass of water out of the freezer the ice would melt turning into water again this is a physical chain but the substance is still the same interesting right now let's take a closer look at mixtures mixtures a mixture is a combination of two or more pure substances there are two types of mixtures homogeneous and heterogeneous let's look closer at each one of these two groups in homogeneous mixtures it's impossible to pick out each component they are not visible to the eye solutions like water with salt or chocolate milk are homogeneous mixtures can you think of another example of a food that is a homogeneous mixture and that we use a lot in cooking mayonnaise is a great example it's made with eggs oil and salt in this case substances can be found in any state of matter solid liquid or gas an example of this would be water with oil or salad i'm trying to write all this down i don't want to miss anything would you like to practice what we learned come on let's classify these substances and mixtures together what do we have here wow chocolate milkshake what kind of substance or mixture is it this chocolate milkshake is a homogeneous mixture because its components can't be seen with the naked eye it's water and you remember what type of substance is water water is a pure substance because in a physical change its composition would stay the same one more this is a tomato lettuce and corn salad it looks so yummy how would we classify this as a substance or a mixture this salad is a heterogeneous mixture because we can clearly see all components with the naked eye way to go you did great thank you for helping me study for my exam i'm sure i'm gonna score well see you soon [Music] we've learned so much in just one video did you know there are many more videos imagine how much you could learn subscribe to the smile and learn educational channel to learn and have fun at the same time