Mass Definition: The amount of matter in an object. Units: grams or g

Volume The space occupied by an object or substance ml or cm3

Determining the Volume Regular Solid (units cm3) V = l x w x h Irregular Solid (units mL) Water displacement Submerge object in water Measure water level before and after object is added Subtract the difference Volume of Object = Water level After –Water level Before

Measuring Volume Reading the Meniscus at eye level

Measuring Volume Determine the Volume Readings… Using Proper Significant Figures

Volume Lab Challenge

Lab Challenge! How can we measure the volume of an object? What can we use to measure???

Materials at your lab table See me for other items What is the volume of an object? Purpose: Determine the volume of 2 regular objects and 2 irregular objects. Procedure: Design how you would determine the volume Goals: Determine the volume Check in with me to describe your procedure Materials 2 regular objects 2 irregular objects Materials at your lab table See me for other items

Shortcomings of Volume

Cork contains air space and it floats in water making it difficult to find its correct volume.

Answer the following Questions What are the units for volume? When doing a measurement what should the last number you write down represent? How do you take the volume of an irregular solid?

Introduction

Explain why the set up looks like this. How could we get the boxes to balance? Why is it balanced? (is it just equal numbers?)

Steel Ball vs. Marble What is it about the steel ball that makes the system unbalanced? What would it take to balance the system?

Analysis What are some similarities and differences between the steel ball and the marble? Why is one “heavier” that the other if they are the same size? In what ways could the atoms differ between the two objects?

Heavier substance has heavier atoms Heavier substance has atoms that are more tightly packed

Mass vs. Volume Lab So what is the relationship between mass and volume?? Purpose: To graphically and mathematically determine the relationship between mass and volume

Mass vs. Volume Lab Each group is going to be given a piece of metal Your objective is to determine… Mass of your object Volume of your object We will record the class data We will create a graph Mass (g) Volume (mL)

REMINDER Why would we want to… Find the mass of the object before the volume? So that the water from the water displacement doesn’t change the mass

M vs. V Class Data Object Mass (g) Volume (mL) 1 13 2 14 3 15 4 16 6 17 7 18 8 19 9 10 11 27 12 117

Homework Finish your graph WS #1

Homework Finish your graph WS #1

Summarize So…. Based on the results of our mass vs. volume lab… Does the size, shape or amount of a substance change it’s density?

Density Notes

Which is more DENSE? Golf ball or a ping pong ball They are the same SIZE, SHAPE, COLOR, VOLUME

So, what is the relationship between mass and volume? DENSITY! How much “stuff” is packed into a given space. It’s the “mass per volume”

What is Density? Density is a Characteristic property of matter. It will always be the same for a kind of matter regardless of shape or size. Describes how tightly packed together atoms are in different materials.

Consider the diagram above. Which circle, A and B, is more dense? If you said A, YOU’RE CORRECT! Since A has more particles (mass) in the same volume as B, A would be more dense.

Equation g/cm3 OR g/mL Density = mass volume Units: g/cm3 Density is the ratio of mass to volume. That means you DIVIDE the mass of your object by the volume. Density = mass volume Units: g/cm3 V D M g/cm3 OR g/mL

(Sample Problem) A 13.0 gram piece of aluminum has a volume of 4.8 cm3. What is the density of the aluminum? G U E S

Bell Ringer A graduated cylinder is filled with 27.21 mL of water. A 13.0 gram piece of solid is placed into the graduated cylinder causing the water to rise to 32.01 mL. What is the density of the solid? Using IPS pg 58, identify the solid. G U E S

Layering Liquids Lab Density of Liquids

Purpose: To make a graduated cylinder of 5 colored liquids that is layered according to their densities. Prediction: Where will the liquids with the greater density stay (close to the bottom or close to the top)?

Procedure Determine the densities of 5 liquids. Identify each liquid (use IPS pg 58 or CPS pg 107) Make a data table recording your data. Make a prediction how the liquids will layer when poured into a cylinder using the lab diagram. Carefully layer the liquids into a graduated cylinder, using 5-10 mL for each layer. (pour slowly) Select 2 objects from the table to drop into your layered liquids. Predict which layer they will float in.

Properties of Density Heavy vs. Light Many times when we talk about things being heavy or light what we are really talking about density. The reason things are “heavy” is because it has a high density and has a greater mass than expected for its volume. Sink vs. Float Matter that floats has a lighter density than the substance it is in Matter that sinks has a greater density than the substance it is in

Do liquids have different densities? Which liquid is oil, Which liquid is water? What are the other liquids?

Predictions: Why? Coke vs. Diet Coke, which one has a greater density? If you think of hot and cold water, which has a greater density, hot water or cold water? If you think of Carbon Dioxide gas, which has a greater density, Carbon Dioxide or the “regular” air?

Density of a Gas

How do densities of substances compare? Look at table in your packet What is the range of densities for solids? 0.6 – 22.5 g/cc What is the range of densities for liquids? 0.07 – 1.6 g/cc What is the range of densities for gases? 10-5 – 10-3 g/cc 0.0018 to 0.00084 g/cc

Do gases have density?

Problems to do right now in your notes. A parking lot is filled with automobiles. Does the number of wheels in the lot depend upon the number of autos? Does the number of wheels per auto depend upon the number or autos? Is the number of wheels per automobile a characteristic property of autos that distinguishes them from other vehicles?

A student has several different amounts of substances A,B, and C A student has several different amounts of substances A,B, and C. She measures the masses and volumes of these samples and plots the graph shown. Which substance has the greatest density? How do you know?