Monday September 21, 2009 Day 4- EVEN Homework: NONE

Do Now:  Why do you think some objects float and others sink? ◦ EXPLAIN YOUR ANSWER!  Homework: NONE

Float or Sink?

Will a can of soda float or sink? Does it matter what kind of soda we use?

What makes one can float and another sink? Does it depend on the object ’ s size? Same Volume Volume (cm3,mL) (Amount of space occupied)

What makes one can float and another sink? How about the mass? Different Mass Amount of matter that an object contains (g)

Density (g/cm 3 or g/L) Amount of substance contained within a given space Density = mass/volume

Which cube is more dense? AB A - has more mass per unit of volume

Another way to think about it …

As the volume remained the same …. …. the mass increased. Did the density of the bus increase or decrease? Increased

Let ’ s try some other objects … Golf ball Styrofoam ball Can of Diet Coke Can of Coke Wooden ballPaperclip

Tuesday, September 22 nd Homework: NONE

Do Now:  Complete #6- Float or Sink  Record the data from “Float or Sink”  Calculate the densities of each object and record ◦ Try to determine whether the object will float or sink  Complete #8  Homework: NONE ObjectMassVolume 1Diet Soda g 355 mL 2Regular Soda g 355 mL 3Golf Ball 45.8 g 40 mL 4 Wooden Ball 84.6 g 110 mL 5 Styro- foam 3.5 g11 mL 6Paper Clip 1.5 g0.7 mL

What is density? What does it involve? Objects float on top of the liquid. Water is on the bottom, because it was poured in first. Density is the thickness of something The more air pockets in something the more it will float. Wax, ice, has lots of air pockets in it and floats. Liquids are liquids and will all mix together Weight determines if an object will sink or float. Heavy objects always sink and light objects always float. A larger heavier object will not float as well as a smaller lighter object of the same material. The amount of water will cause objects to float or sink better. There must be more water for larger objects to float. Weight of the water must be more than the weight of the object. Objects with holes will always sink.

Will it float in water? Determine if the following shapes will float in water by calculating the density for each item. Density = Mass / Volume Mass: 15 g Volume: 20 mL Mass: 1000 g Volume: 50 mL Mass: 225 g Volume: 100 mL Mass: 10 g Volume: 200 mL If the density is less than 1.0 g/mL then it will float.

Will it float in water? Determine if the following shapes will float in water by calculating the density for each item. Density = Mass / Volume Mass: 15 g Volume: 20 mL Density: 0.75 g/mL Mass: 1000 g Volume: 50 mL Density: 20.0 g/mL Mass: 225 g Volume: 100 mL Density: 2.25 g/mL Mass: 10 g Volume: 200 mL Density: 0.05 g/mL If the density is less than 1.0 g/mL then it will float.

 How are you going to measure the mass?  What are the units for mass? grams (g)

Liquids = milliliters (mL)

Volume = a x a x a = a 3 Volume = (4/3)πr 3 (Length x width x height)

METRIC!!!! 5.40 cm

3.20 cm 4.50 cm Volume = cm cm x 3.20 cm x 4.50 cm

Volume = cm g / cm 3 Density = 1.7 g/cm 3

1 g/mL = 1 g/cm 3 (liquids)(solids)

Calculating Density of a Liquid Do Now: Fill out the Hearing Screening Form Name, Grade/HR Volume of a Liquid Finish Calculating Density Lab Homework: Density Calculations

Identify the following lab equipment: Identify the following lab equipment:

Test tubes

Meniscus 9.0 mL

50 mL 45 mL 40 mL 45.0 mL

95 mL 85 mL Is it more or less dense than water? 0.4 g/mL Less dense than water

 Do Now:  Come up with as many words possible associated with Density (WORDSTORMING)  Take HW out to be checked  HW- NONE

TABLE OF CONTENTS 11. Float or Sink? 12. Calculating Density Lab I  I HAVE, IF NOT, YOU NEED TO HAND IT IN 13. Density Calculations WS 14. Wordstorming: DENSITY 15. Calculating Density Lab II 16. Archimedes and the Golden Crown 17. Calculating Density Lab III Do Now: Organize Binder _________________________ When finished, read Archimedes and the Golden Crown Solve the dilemma Calculating Density II and III Homework: NONEHomework: NONE Unless you have Lab Calculations to finishUnless you have Lab Calculations to finish

Archimedes and the Golden Crown

The king wants to pick out a new crown but only wants one made of 100% pure gold, not gold plated or mixed with other metals. Can you help him find his new gold crown? The volume of each crown is 60 cm 3 D = M / V A = g B = 534 g C = 1,158 gD = 1,284 g

Densities of Metals Lead – g/cm 3 Gold g/cm 3 Silver g/cm 3 Platinum g/cm 3 Copper - 8.9g/cm 3 D = M / V A = g B = 534 g C = 1,158 g D = 1,284 g The volume of each crown is 60 cm 3

 Do Now: ◦ Directions for Density Sketch ◦ Finish Calculating Density Lab III  Show me Lab II and III ◦ Work on Density Sketch with group from Density Labs ◦ When finished, MORE DENSITY PRACTICE! Homework: Read pg and complete Review and Reinforce 1-2

 Step-by-Step procedure for calculating density ◦ Regular solid ◦ Liquid ◦ Irregular solid  Formula for calculating density (UNITS)  Picture that demonstrates density  Definition of density