1. Lesson 3: Mass T. Trimpe 2008 http://sciencespot.net/

2. English vs. Metric Units Which is larger? 1. 1 Pound or 100 Grams 2. 1 Kilogram or 1 Pound 3. 1 Ounce or 1000 Milligrams 1 pound = 453.6 grams 100 kilogram = 220 pounds 1 ounce of gold = 28,349.5 milligrams

3. Metric Units Mass refers to the amount of matter in an object. The base unit of mass in the metric system in the kilogram and is represented by kg. Standard: 1 kilogram is equal to the mass of the International Prototype Kilogram (IPK), a platinum-iridium cylinder kept by the BIPM at Sèvres, France. Metric Units 1 Kilogram (kg) = 1000 Grams (g) 1 Gram (g) = 1000 Milligrams (mg) Which is larger? A. 1 kilogram or 1500 grams B. 1200 milligrams or 1 gram C. 12 milligrams or 12 kilograms D. 4 kilograms or 4500 grams Click the image to watch a short video about mass. Kilogram Prototype Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram

4. Measuring Mass We will be using digital balances to find the mass of various objects. Be sure the balance is sitting on a flat, level surface.

5. Measuring Mass 1 st – Turn the balance on using the on/off/zero button. 2 nd – Wait until the display reads 0.00g. 3 rd – If weighing a sample of liquid or granulated solids, place the empty container on the scale first. 4 th – Make sure the display reads 0.00 g before adding your sample. 5 th – Record the mass of the object to the first decimal (1/10 of a gram).

6. Measuring Mass Watch this short video on using a digital balance.

7. 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. Density

8. Which one is more dense? Demonstration: People in a square How about this: Which square is more dense?

9. Which one is more dense? Now which one is more dense?

10. To find the density 3- Divide Density = Mass g Volume c³ Density = g/cm 3 1- Find the mass of the object 2- Find the volume of the object 1- Find the mass of the object ALWAYS REMEMBER UNITS!

11. 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.

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: Mass = 35 grams Volume = 7 cm 3 Unknown: Density (g/ cm 3 ) Formula: D = M / V Solution: D = M / V D = 35g/7 cm3 D = 5 g/cm3

13. Frank has a paper clip. It has a mass of 9g and a volume of 3cm 3. What is its density? Write the Formula: D = M/V Insert the numbers: D = ____________ / ___________ Calculate the answer:D = ___________________ (Don’t forget UNITS) Frank also has an eraser. It has a mass of 3g, and a volume of 1cm 3. What is its density? Write the Formula: D = M/V Insert the numbers: D = ____________ / ___________ Calculate the answer:D = __________________ (Don’t forget UNITS) Practice

14. Frank has a paper clip. It has a mass of 9g and a volume of 3cm 3. What is its density? Write the Formula: D = M/V Insert the numbers: D = 9g / 3cm 3 Calculate the answer:D = 3 g/cm 3 Frank also has an eraser. It has a mass of 3g, and a volume of 1cm 3. What is its density? Write the Formula: D = M/V Insert the numbers: D = 3g / 1cm 3 Calculate the answer:D = 3 g /cm 3 Practice