2. Physical Properties of Matter So many ways to describe matter!

3. What are Physical Properties? Well, we know that all matter has mass (it’s made of stuff) and it has volume (takes up an amount of space). It doesn’t matter if it’s a fleaor a whale …it’s made of matter. The most enormous stars and the tiniest, microscopic air molecules are matter, too.

4. Yes, and…? But matter has properties beyond just “mass” and “volume,” right? I mean, after all, if I asked you to describe this object here: …you wouldn’t just tell me, “It has a mass of 34 grams and a volume of 23 milliliters.” You’d use words like delicious, gooey, yummy, soft, smells good, and so on and so on. Well, as nice as it would be to just use whatever adjectives we wanted to describe matter, there are a few that we use all the time that count as physical properties. This is the important part… it’s a way to describe a substance WITHOUT changing it into a new substance, it’s a physical property!

5. S. Ramsay 2004-5 Physical Properties Physical properties Physical properties are those characteristics of a substance that can be observed with the senses. Examples: Color Shape Textur e Melting point Boiling point Density Texture

6. COLOR Well, it might be pretty simple to say that a frog is green or jeans are blue or Joe is red, but there’s some pretty technical reasons for why things have colors. The point is that you can describe a substance’s color without changing it into a new substance.

7. LUSTER Ooohhh…look at that biscuit.Ooohhh…look at this gold ring. I desire the one on the left for its tastiness. I desire the one on the right for its LUSTER. Luster describes how shiny a substance is.

8. TEXTURE Some things are smooth. Others are rough. That’s texture for you.

9. ODOR A substance that gives off an odor, whether good or bad, isn’t being changed as it does so! Odor – describes the smell of a substance.

10. HARDNESS This one can be a little confusing. You’ve probably heard that the hardest substance on Earth is ___________. That means that a diamond can cut any other substance you can think of, even metals. The only thing that can cut a diamond is a slightly more pure diamond! However, that doesn’t mean that diamonds are stronger than anything else. I’d much rather live in a brick or steel house than a diamond one. Keep your bricks. I’ll take the diamonds!

11. CONDUCTIVITY Some substances allow forms of energy, such as heat, sound, and electricity, to flow through them very easily. Apparently, Joe is one of those substances. These substances are very useful for things like:

12. Conductivity, contd. But other substances are useful to us because they’re NOT good conductors. We call those insulators. Conductivity – describes how well a substance allows heat or electricity to flow through it. Low conductivity substances are called “insulators.”

13. MALLEABILITY What do these substances have in common? If you said that they can be pounded with a mallet or hammer or fist or forehead into new shapes easily, then you’re right! Malleability – describes how easily a substance can be formed into new shapes. Opposite of “brittle.”

14. DUCTILITY What do THESE substances have in common? Well, of course…they’re all ductile! That just means they can be stretched or drawn into wires without falling apart or breaking. Ductility – describes how well a substance can be pulled into thin wires.

15. MAGNETISM I’m not sure how much to say about this. Some substances are magnetic, others aren’t. Magnetism – describes if a substance attracts or repels magnets.

16. SOLUBILITY What happens if you take sugar, salt, or kool-aid powder and stir it into water? But you haven’t made a new substance. The kool-aid and water have just mixed super well because the kool-aid dissolves so easily in water.

17. Solubility – describes how well a substance dissolves in another substance like sugar stirred in water. The sugar and water have NOT made a new substance! The Kool-Aid and Water are Separate? Yep. If you had the world’s best microscope, you could see bits of red kool-aid floating around in clear water. Our eyes just aren’t good enough to see things that small so it looks like a consistent, red liquid. If you tried the same thing with rocks, you’d just have a glass full of wet rocks. Rocks aren’t soluble, but kool-aid is!

18. STATE OF MATTER A lot of you remembered that matter comes in three states: SOLID LIQUID GAS Whether a substance is solid, liquid, or gas is a physical property. You can easily tell me what it is without having to change the substance. State of Matter – describes whether a substance is solid, liquid, or gas.

19. MELTING & FREEZING POINT At what temperature does an ice cube melt into water? At what temperature does liquid water freeze into ice? SAME ANSWER! 32 0 F or 0 0 Celsius. This is a property of water…that 0 0 Celsius is a magical temperature for this particular substance. Above this temperature it stays liquid, but below it, it freezes to solid. NOTICE that it is still just a physical property because the water changes, but not into any new substance! Melting & Freezing Point – describes the temperature at which a solid turns liquid or vice versa.

20. BOILING & CONDENSATION POINT Likewise, what’s the magic temperature for water at which the liquid becomes a gas vapor? Yes, 212 0 F or 100 0 Celsius. Boiling & Condensation Point – describes the temperature at which a liquid turns gas or vice versa.

21. DENSITY Density is a weird one. You know by now that all matter has mass and volume. But density tries to describe how “packed in” the mass is within that volume. In other words, how compact is the stuff? This golf ball and marshmallow are about the same size (volume). But which is going to have more mass? The golf ball has way more mass. Since they’re about the same size, you know that the golf ball has a higher density.

22. Density, contd. What’s heavier…a pound of steel or a pound of feathers? Well, a pound is a pound, so they have the same weight. But what would those two piles of objects look like? Hi, Joe. Yo. A pound of steel, yeah. And a pound of feathers. It’s clear steel is WAY more dense than feathers.

23. More on Density Don’t forget! Gases and liquids have densities too! That’s why when a lot of substances are put in the same container, they often form layers based on their densities!

24. Evidence of a Physical Change Change in: Location Shape Size Phase Physical change – a change that affects one or more physical properties of a substance. It does not change the identity of the matter involved.

25. Physical Change Substance may seem different, but the way the atoms link up is the same.

26. It’s a physical change if It changes shape or size It dissolves.

27. It changes phase (freezes, boils, evaporates, condenses) It’s a physical change if...

28. Review All these properties that we described are physical properties. This just means that they are ways that scientists commonly describe substances without having to change them into a new substance. Remember this? You should be able to go down your list of physical properties and decide which this cookie has or doesn’t have. And then eat it!