1. Measuring density Thursday 9/17/09

2. What density is and how to measure it What we will learn…

3. PowerPoint and video Notes Worksheet Lab (only if you complete the worksheet) How we will learn it…

4. From Tuesday Ruler: http://www.k12math.com/math-concepts/measurement/ruler-cm.jpg Mass: the amount of matter in an object Metric System: Mass 1 milligram is like a few grains of salt 1 gram is like a paper clip 1 kilogram is like a textbook 1 gram (g) = 1000 milligram (mg) 1 kilogram (kg)= 1000 gram (g)

5. From Yesterday Metric System: Length Base unit is the meter “m” 1 centimeter is as big as the tip of your pinky 1 millimeter is as big as a dime on its edge 1 meter (m)=100 centimeters (cm) 1 meter (m)=1000 millimeters (mm) 1 centimeter (cm)=10 millimeters (mm) 1 kilometer (km)100 meters (m)

6. From Wednesday Ruler: http://www.k12math.com/math-concepts/measurement/ruler-cm.jpg Volume: the amount of space something takes up The base unit of volume is the liter “L” or “l”. Standard: 1 liter is equal to one cubic decimeter Metric System: Volume 1 liter (l)= _____ milliliter (ml)

7. From Thursday Ruler: http://www.k12math.com/math-concepts/measurement/ruler-cm.jpg Mass: the amount of matter in an object Base unit is the kilogram “kg” 1 milligram is like a few grains of _______ 1 gram is like a _________ 1 kilogram is like a ________________ 1 gram (g) = _____ milligram (mg) 1 kilogram (kg)= _____ gram (g)

8. Density is defined as mass per unit volume. It is a measure of how tightly packed and how heavy the molecules are in an object. Density is the amount of matter within a certain volume.

9. Which do you think would have the greater density? Why? 1 kg of feathers1 kg of rock

10. Proof that water and ice have different densities

11. To find the density 1- Find the mass of the object 2- Find the volume of the object 3- Divide Density = Mass Volume

12. 1)Find the mass of the object 2)Find the volume of the object 3)Divide : Density = Mass - Volume To find density : Ex. If the mass of an object is 35 grams and it takes up 7 cm 3 of space, calculate the density. Set up your density problems like this: Given: Mass = 35 gramsUnknown: Density (g/ cm 3 ) Volume = 7 cm 3 Formula: D = M / VSolution: D = 35g/7 cm 3 D = 5 g/cm 3

13. Practice Problems 1. A small block of wood floats on water. It has a volume of 25 cubic centimeters and a mass of 20 grams. What is the density of the wood? M=20 g V =25 cm D= 0.8g/cm 3

14. Practice Problems 2. A ample of liquid has a mass of 24 grams and a volume of 16 milliliters. What is the density of the liquid? M=24 g V =16 cm D= 1.5 g/ml 3

15. Practice Problems 3. A metal sample has a mass of 43.5 grams and a volume of 15 cubic centimeters. What is its density? M=43.5 g V =15 cm D= 2.9 g/cm 3

16. Another Way of Looking at It You will often hear density referred to as “mass per unit volume.” Mass is how much matter the object has. Per simply means divided by Unit volume is a measure of how much space it takes up When you hear mass per unit volume, you should think… Take the mass and divide by its volume!

17. Notes on Density Density is the measure of how much mass is contained in a given volume. Density = Mass /Volume (mass divided by volume) Solids -- g/cm 3 Liquids -- g/ml (1 ml is 1 cm 3 ) Density of water is 1.00 g/ml 3