Presentation on theme: "Do Now for 10/3/13 Take out A9 Lab Report HW: Complete Procedure Part C Benchmark Assessment about density on Tomorrow."— Presentation transcript:
Do Now for 10/3/13 Take out A9 Lab Report HW: Complete Procedure Part C Benchmark Assessment about density on Tomorrow
A9 Measuring mass, calculating density Today’s Target: I will be able to accurately calculate the density of the six objects at my station.density Review lab procedures Review lab safety Gather data Part C – Complete for homework
A9 Measuring mass, calculating density Density – The amount of mass (stuff) in a given unit of volume. The amount of stuff packed into a given unit of space. We’re going to measure the densities of our various objects. Open books to activity A9 beginning on page A-36.
A9 Measuring mass, calculating density Lab safety – Wash hands when finished gathering data. Equation for finding density: – Density = mass/volume -OR- D = m/v – Units for density: grams per cubic centimeter g/cm 3 Where can you find information about the volume of the objects? – Student sheet 8.1b Make sure you complete both tables. Use of the balance. Use of the balance
A9 Measuring Mass, Calculating Density ObjectMass (g)Volume (cm 3 or mL) Density Calculation Density (g/cm 3 or g/mL) Light gray bar Dark gray bar Light gray cube Dark gray cube Light gray cylinder Dark gray cylinder
A9 Identifying Objects’ Material Using Density ObjectDensity Calculated Closest Density from Table 3 Object’s Material Light gray bar Dark gray bar Light gray cube Dark gray cube Light gray cylinder Dark gray cylinder
A9 Measuring mass, calculating density ObjectMass (g)Volume (cm 3 or mL) Density Calculation Density (g/cm 3 or g/mL) Light gray bar /7.2=3.0 Dark gray bar /7.2=8.6 Light gray cube /15.6=2.9 g/cm 3 Dark gray cube /15.6=8.2 g/cm 3 Light gray cylinder /5.7=2.9 Dark gray cylinder /5.7=8.9 From Student sheet 8.1b
A9 Measuring mass, calculating density ObjectDensity Calculated g/cm 3 or g/mL Closest density from Table 3 Object’s material Light gray bar3.0 Dark gray bar8.6 Light gray cube2.9 Dark gray cube8.2 Light gray cylinder2.9 Dark gray cylinder8.9
A9 Measuring mass, calculating density ObjectDensity Calculated g/cm 3 or g/mL Closest density from Table 3 Object’s material Light gray bar3.02.7Aluminum Dark gray bar8.67.9Iron Light gray cube2.92.7Aluminum Dark gray cube8.27.9Iron Light gray cylinder2.92.7Aluminum Dark gray cylinder8.97.9Iron
A9 Measuring mass, calculating density Do Now for 10/8/13 – Take out A9 write up. – HW: Study for density quiz Thursday – Bring a calculator Further developed answer to 3E due Thursday
A9 Measuring mass, calculating density Today’s Target: I will Learn how to calculate density and see how it can be used to identify different substances. Check HW – Check HW Yesterday’s Exit Ticket questions Discuss Data Go over analysis questions Key Points Vocabulary
A9 Measuring mass, calculating density Important to Note: There is a degree of uncertainty in using density to identify unknown solids. Most metals have impurities or are alloys (mixtures of metals) and therefore can have a whole range of densities.
A9 Measuring mass, calculating density Analysis 1. What material is each metallic solid made of? Use data from this activity to support your explanation.
2. Now that you have identified what each solid is made of, look at the hazards for each in Table 2 in Activity 7 (page A-31). What safety precautions must be taken when working with these materials? – Iron – – Aluminum -
A9 Measuring mass, calculating density 3. A block of wood is 4 cm wide, 5 cm long, and 10 cm high. It’s mass is 100 grams. – A. Calculate its volume – B. Calculate its density – C. Will the wood float or sink in water? Explain.
– D. Imagine cutting the block into two exactly equal halves. Calculate the volume, mass and density of each piece. 4 cm 5 cm 10 cm 100 g 5 cm 4 cm 5 cm Mass?
A9 Measuring mass, calculating density Develop an answer to letter E to hand in on Thursday. MAKE SURE YOU INCLUDE A DIAGRAM.
Exit Ticket Take out a 3x5 card and write: Your name, date, and period in the upper right hand corner. Answer the following question: – Why were the density numbers we calculated so far off from the actual densities of our objects?
WATCH THE FOLLOWING You-tube clips to learn more about density!! Cool density experiment you can try at home!! – What if you are trying to find the density of an “irregular” object ? – f5FBvtJ7T0&feature=related&safety_mode=true&persist_safety_mode=1 f5FBvtJ7T0&feature=related&safety_mode=true&persist_safety_mode=1 One more cool experiment! – Student designed experiment!! – ode=1 ode=1
Key Concepts: 1. Substances have characteristic properties, such as density, that are independent of the amount of the sample. Ex. 2. Measurements and mathematics are important in all aspects of scientific inquiry. – Ex.
A9 Measuring mass, calculating density Vocabulary – Density- A7 – qualitative A8 – quantitativeA8 – volume A8 – 1. Mass: The amount of matter in an object. – 2. Weight: The vertical force exerted by a mass as a result of gravity.
Do Now for 10/11/12 Review for Quiz HW: #3E from Activity A9 is due tomorrow. Make sure it’s on a separate sheet of paper. Read and write up A10
A10 Density of Unknown Solids Create a procedure to find the density of unknown solids from our original mixture. You should have: – Materials list – Safety precautions – DETAILED procedure steps – Data table Consider: – Which equipment and procedures will give you the most accurate measurements – Record your measurements for length to the nearest 0.1 cm. If you are measuring volume in mL, round to the nearest mL. – Be specific!!!