Density

Warm Up: (5 min) 1.What is density? What is a job that requires knowledge about density? 2.What is happening in the picture to the right? 3.If I have a can of coke and I put it in a bowl of water, will it sink or float? What about a can of diet coke?

Today’s Notes (UNIT 2!!!) HAPPY OCTOBER Title the page: Density Date in upper right corner No talking while I’m talking Raise your hand and wait to be called on before you speak

Terms DENSITY (D) : an object’s mass per unit volumemassvolume LOW DENSITY (less than 1.00) – object floats in water HIGH DENSITY(greater than 1.00) – object sinks in water MASS (m): the amount of matter in an object VOLUME (V): the three dimensional (3-D) space an object occupies

Definition of Density Density: the amount of matter per unit of volume of an object But what does that really mean?

Compare Thing 1 and Thing 2 Thing 1Thing 2 Which of these has more matter? Which has more volume? So which one is the most dense? THING 2 SAME VOLUME THING 2

Compare Thing 1 and Thing 2 Thing 1Thing 2 Matter Matter VolumeVolume Less dense More dense

Compare Thing 3 and Thing 4 Thing 3 Thing 4 Which of these has more matter? Which has more volume? So which one is the most dense? More dense Less dense THING 3 THING 4 SAME MATTER

Definition of Density Density: the amount of matter per unit of space of an object But what does that really mean? (2 MINS, 2 SENTENCES) How compact or packed together the matter is in the space of an object.

Apply it to real life: More sugarLess sugar What makes Coke different from diet Coke?

So what can we conclude about density? More dense Less dense

Liquid Layers – Check it out! Which liquid has the highest density? Which liquid has the lowest density? Which liquid has the middle density? Can you tell the density of something by looking at it?

Definition of Density Density: the amount of matter per unit of volume of an object Matter: per:Space: Mass Volume

Formula for Density p = m V TERMVARIABLEUNITS DensityD or pg/mL OR g/cm 3 Massmg VolumeVmL OR cm 3

Units 1. What other Units of mass do you know? 2.Units of VOLUME and DENSITY match up: Volume in (mL)Volume in ( cm 3 ) Density in (g/mL)Density in (g/ cm 3 )

Example 1 Osmium is a very dense metal. What is its density if g of the metal occupies a volume of 2.22 cm 3 ? lecturePLUS Timberlake 16

Solution p = mass = g = volume2.22 cm 3 = g/cm 3 = 22.5 g/cm 3 lecturePLUS Timberlake 17

Will the Osmium float or sink in water? In the problem we calculated Osmium had a density of 22.5 g/cm 3 Remember the density of water is 1.00 g/cm g/cm 3 > 1.00 g/cm 3 Osmium is MORE dense therefore it will SINK

Independent Practice Density Practice 1 Class Set!!! Show work on paper Complete only the front side DUE AT THE END OF CLASS TODAY

Section 2-Complex Word Problems

Warm Warm Up: (5 min) Turn in 3 problems The density equation is p = m V 1.What would the equation look like if you were solving for mass (m)? 2.What would the equation look like if you were solving for volume (V)? HINT: move the letters around

Today’s Notes Title the page: Complex Density Problems Date in upper right corner No talking while I’m talking Raise your hand and wait to be called on before you speak

Two Types of Complex Problems 1.Rearranging Equation Problems 2.Volume of submerged objects Class Overlook: A quick example of both types Work time

Practice 1 : Rearranging Do NOT copy the problem Show your work in your notes 1.Water has a known density of 1.00 g/mL. Will Cray wants to know exactly how many mL of water are in his glass so he weighs the glass and finds the water inside has a weight of 30.9 g. What is the volume of the water in his glass?

Answer 1 V = m  V = 30.9 g  V = 30.9 mL p 1.00 g/mL

lecturePLUS Timberlake 26 Practice 2: Submerged Objects What is the density of 48 g of a metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 mL? 33 mL 25 mL

lecturePLUS Timberlake 27 Solution 2 Volume (mL) of water displaced = 33 mL - 25 mL= 8 mL D = mass = 48 g = volume 8 mL = 6 g/mL

Independent Practice 1.Complete density practice 1 2.Complete density practice 2 (backside) 3.Complete three problems on projector slide (ON SEPARATE PAPER - - THEN STAPLE! & put on INBOX Table) DO NOT COPY PROBLEMS SHOW WORK IF YOU FINISH THAT: If you finish those come get your homework from me and you can work on that in class

Practice Problems – Rearranging Show work on a separate sheet Do NOT copy the questions 1. Will Cray takes the same glass and fills it with orange juice so it is at the same volume (30.9 mL). The OJ weighs 61.8 g. What is the density of the OJ? 2. Without a balance we can calculate the weight of a liquid if we know its volume and density. What is the mass of 11.2 mL of a liquid with a density of 6.3 g/mL? 3. Calculate how many milliliters of a liquid are in the beaker given the following information: The beaker weighs 50 g The beaker plus liquid weighs 64 g The density of the liquid is 7 g/mL

Turn In Work on a separate sheet for Density Practice 1 and Density Practice 2 and Practice Problems – Rearranging TURN IN DENSITY 1 & 2 ON INBOX TABLE Grab a HW assignment from stool by word wall (DENSITY 3) NAME, STAPLE TOGETHER, TURN IN

Homework Half-Sheet Density Practice 3, complete by next class 100% STOOLS UP AT BELL Push Chairs In