Density

1. Density

2. Remember Back Volume � Amount of SPACE something takes up. It is 3-Dimensional Mass - Amount of MATTER something is made of.

3. Remember Back Volume � Measured in milliliters (mL) or in cubic centimeters (cm�) Mass - Measured in grams (g).

4. Remember Back So volume indicates how BIG something is and�. Mass indicates how HEAVY something is.

5. Put it Together Density is a combination of volume and mass. Density is the �amount of matter in a given volume�. The amount of �stuff� in a certain �space� Describes how heavy something is for its size

6. Units for Density Just like length, volume and mass, density has to be labeled with the correct units. g/cm� or g/mL is the standard unit for density. Remember that a cm� is basically the same as a mL.

7. What is the density of an object that has a mass of 20 g and a volume of 5 cm3?

8. Ms. Levy invented a new type of peanut butter candy that you eat after disco dancing. She measures the mass to be 25 g and the volume to be 5 cm3. She calculates that the density is 5.0 g/cm3. When she places it in a beaker full of water it sinks.

9. Since it sinks in water, what does that tell you about the density of the item?

10. You are going swimming in the Dead Sea. You walk to the edge of the water and see the following people in the water.

13. How could this happen? How is it related to density?

14. Density is the mass per unit volume of an object. It tells us how closely packed the matter is in an object. The denser the object, the closer together the matter is. It can help us identify the type of matter that we have.

15. A block has a mass of 55 g and occupies a space of 44 mL. What is the density of this object in g/mL? Density = Mass Volume Density = 55 g 44 mL Density = 1.25 g/mL

16. What would happen to this block if we placed it in pure water at 20 degrees Celsius?

17. Since the block has a density greater than 1 g/mL, it would sink in pure water at 20 degrees Celsius.

18. What is the density of this rock if it has a mass of 120g?

19. Density = Mass Volume Density = 120 g 50 mL Density = 2.4 g/mL

20. Look at the picture to the right. It is supposed to be a graduated cylinder with different liquids in it. What is the order of the liquids from the least dense to the most dense?

25. That is why large ships float. They are less dense than water.

26. Which is more dense?

28. Can DENSITY change?

29. An object�s density is not constant. A change in volume will change its density.

30. A decrease in volume causes an increase in density. There are now the same number of molecules in less space. It has become more compressed!

31. An increase in volume causes a decrease in density. The same number of molecules are now spread further apart from each other. It has become �fluffier�!

32. Volume changes are due to compression or expansion of an object. This can be caused by a change in TEMPERATURE or a change in PRESSURE.

33. Diamonds are really dense coal. Coal is compressed below earth�s surface.

34. Atoms are packed into a smaller volume, and are rearranged.

35. Then you get a diamond. Same make up as coal, just more dense.

36. The air inside of a hot air balloon is heated by a torch. Air heats up and expands.

37. All objects except water expand when heated. Same matter expanded into a bigger space.

38. The air in the balloon is now less dense than air outside, and it rises.