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Cube Activity pg. 69  Question: Do cubes of exactly the same size and shape have the same mass?

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Presentation on theme: "Cube Activity pg. 69  Question: Do cubes of exactly the same size and shape have the same mass?"— Presentation transcript:

1 Cube Activity pg. 69  Question: Do cubes of exactly the same size and shape have the same mass?

2 Analysis Questions  1) Give an explanation as WHY one feels heavier. (what causes an object to have a different mass from another)  2) Description of cube – color, size, shape Picture of arrangement of the molecules Mass (g) Volume (cm 3 ) 1)Gold cube ) Silver cube

3 Correct Arrangement  Heavy substance-smaller and more compacted molecules  Lighter substance-larger and less Compacted molecules

4 Density Lab pg 70  Problem: How are the volume and mass of a substance related? Hypothesis: If the molecules of one object are smaller and more compact than another, then its density will be greater because there are more molecules in each volume of the denser object.

5 Materials  Two sets of metals of different shapes  Graduated Cylinder  Metric Ruler  Water  Mass balance

6 Procedures 1.Weigh each shape on a mass balance BEFORE measuring the volume 2.Record each shape’s mass in the data table 3.Measure the cubes’ volume using the metric ruler (V=l*w*h) 4.Measure the volume of the other two shapes with the graduated cylinder. 5.Record the volumes in the data table. 6.Graph the data. Create a Volume vs. Mass graph. 7.Make a best fit line for each metal. 8.Find the slope of BOTH lines.

7 Metal ColorShapeMass (g)Volume (mL) Cube Bar Cylinder Cube Bar Cylinder

8 Conclusion-Big Idea from metals Lab pg71.  Objects with the same volume but different masses have Different-DENSITIES  DENSITY: The relationship between the mass of the substance and how much space it takes up.  OR how compact the molecules are in a certain amount of space  Analogy-House Party  WHY DO OBJECTS HAVE DIFFERENT DENSITIES?  The mass of atoms, their size, and how they are arranged determine the density of a substance.

9  What two measurements do you need to find to solve for density= MASS and VOLUME  Formula for Density= Mass/Volume  Units= g/cm 3 or g/mL  How do you find density from your graph? SLOPE  3 equations=  Densities of known substances: Gold 19.3g/cm 3, Steel 7.6g/cm 3 Cooking Oil 0.92g/mL

10 Density Questions-whiteboard and Pg. 36  1) Why do objects have different densities?  2) How might the factors listed in question #1 cause a substance to have a higher density? HINT: Use your answer to #1 to help  3) How might the factors listed in question #1 cause a substance to have a lower density? HINT: Use your answer to #1 to help  4) Draw the arrangement of the molecules for Copper that has a density of 8.9g/cm 3  5) Draw the arrangement of the molecules for Aluminum that has a density of 2.7g/cm 3

11 Pretest pg.31  The following rods have the SAME MASS but different VOLUMES  Predict the densities of each sample by writing- Least dense, Medium dense, Most dense  Explain why you think each rod is either the most, medium, or least dense

12 Unknown Activity pg. 38  Question: Do substances with the same mass but different volumes have the same density?

13  1)  2) Use your calculated density to answer: Do objects with the same mass and different volumes HAVE different DENSIITIES?  3) Draw a picture of the arrangement of the particles for each cube.  4) what can you conclude about the density with objects with the same mass but different volumes?  Pick one-  a) their densities will be the same,  b) the one with the larger volume will have the lower density,  c) the one with the larger volume will have the higher density,  d) the one with the larger density will be twice as dense. Description of the cube-color and shape Mass (g) Volume (cm 3 ) Calculated Density g/cm 3 1) 2)

14 Pg.29 Identifying Unknown Metals Lab  Properties of a substance- how an object looks, feels, act, what it is used for.  Examples- color, texture, smell, mass, volume, density, size, shape, melting point, boiling point

15  Brainstorm: We have a bucket of metals. What property(s) can we use to help identify them?  Problem: What is the identification of each metal?  Hypothesis: If we find the mass and the volume of each metal, then we can identify them because each metal has a specific relationship which is ___________________.  We will find the relationship between mass and volume by using our graph to find the ______________.

16  Data  Data Table #1  Data Table #2  Data Table #3 Color/Description of Metal Volume (cm 3 )Mass (g) Color/Description of Metal Volume (cm 3 )Mass Color/Description of Metal Volume (cm 3 )Mass

17 Graph  Create one graph with three lines!  Graph each data table separately and then create a best fit line.  Use different colors.

18 Data Evaluation  DATA EVALUATION  You will have three data evaluations for each LINE! Do all four steps for each line.  Please also write your slope on the line on the graph.

19 Results MetalReal Name IDENTIFICATIONS Use the information on the board to identify your metal

20 Periodic table  Look at the periodic table.  Which atoms do you think have the greatest density?  Actually the smaller more compacted atoms are more dense.  Density explains why certain atoms make up certain substances. For example  Plastic is made from carbon and hydrogen. These atoms are very light.

21  Based on what you know about the size, mass, and arrangement of atoms, explain why a sample of sulfur is more dense than a sample of calcium.

22 Answer  Even though a sulfur atom has less mass than a calcium atom, many more sulfur atoms can pack together in a certain amount of space.  This gives sulfur more mass per volume than calcium, making it more dense.

23 Analysis questions continue  1) The size, mass, and arrangement of atoms affect the density of a substance.  If a substance has a high density, what can you guess about the size, mass, and arrangement of the atoms that make up the substance?  2) If a substance has a low density, what can you guess about the size, mass, and arrangement of the atoms that make up the substance?


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