Cube Activity pg. 69 Question: Do cubes of exactly the same size and shape have the same mass? 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 (cm3) 1)Gold cube 136 15.62 2) Silver cube 45 15.62 Correct Arrangement Heavy substance-smaller and more compacted molecules Lighter substance-larger and less Compacted molecules 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. Materials Two sets of metals of different shapes Graduated Cylinder Metric Ruler Water Mass balance 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. Metal Color Shape Cube Bar Cylinder Cube Bar Cylinder Mass (g) Volume (mL) 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. What two measurements do you need to find to solve for density= MASS and VOLUME Formula for Density= Mass/Volume Units= g/cm3 or g/mL How do you find density from your graph? SLOPE 3 equations= Densities of known substances: Gold 19.3g/cm3 , Steel 7.6g/cm3 Cooking Oil 0.92g/mL 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/cm3 5) Draw the arrangement of the molecules for Aluminum that has a density of 2.7g/cm3 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 Unknown Activity pg. 38 Question: Do substances with the same mass but different volumes have the same density? Description of Mass 1) the cube-color (g) and shape Volume (cm3 ) Calculated Density g/cm3 1) 2) 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. 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 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 ______________. Data Data Table #1 Color/Description of Metal Volume (cm3) Mass (g) Volume (cm3) Mass Data Table #2 Color/Description of Metal Data Table #3 Color/Description of Metal Volume (cm3) Mass Graph Create one graph with three lines! Graph each data table separately and then create a best fit line. Use different colors. 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. Results IDENTIFICATIONS Use the information on the board to identify your metal Metal Real Name 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. 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. 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. 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?