SNC1D1 Lab: Determine the Density and Identify the Substance Activity 1: Find the Density 1. Get only one of the numbered blocks. Weigh the block to the nearest tenth of a gram (1 decimal point, example: 38.4g) on an electronic scale. Record the mass of the block in Data Table 2 (located on the next page). Record the mass under the heading labeled mass. Make sure you write your answer in the correct row so in row 3 write the mass for Block 3 etc. 2. Measure the length, width and height of the block the nearest tenth in centimetres or millimetres (example: 22.4mm). Be as exact as you can. If your ruler is in millimetres than convert your measurements to cm before recording your measurements in the table. (1cm=10mm). Record the length, width, and height in Data Table 2. Write your answers in the correct space. 3. Calculate the volume of your block using the following formula: V= L x W x H Record the volume of the block in the correct space in Data Table 2. Show your calculations in the space under Data Table 2. 4. Determine the density of the block using the following formula: D = m / V Record the density of the block in the correct space in Data Table 2. Show your calculations in the space under the Data Table 2. 5. Return your block to the box so another group can use it. Repeat steps 1 to 4 for each block. Remember the blocks are not all the same length, width, and height, or mass so you must measure each one! These measurements affect your density calculation, which is how you will identify the block as a specific substance, so it is very important that you do step for each block.
NOTE: There is NO Block 2 Data Table 2 Block Mass (g) Length Width Height Volume Density (g/cm 3 ) Block 1 Block 3 Block 4 Block 5 Block 6 Block 7 Block 8 Block 9 Block 10 Use the space below to show your calculations for volume and density. You may add an extra page if necessary.
Activity 2: Identify the Substance 6. Now that you have calculated the density of each block you can determine what each block is made of. Look at the Density Chart below and compare the densities you found to the densities in the chart below to identify the substance of each block. 7. Write your answers in Substance (Table 3), located below. Density Chart Substance Density (g/cm 3 ) Acrylic 1.1-1.2 Aluminum 2.70 Brass 8.4-8.8 Copper 8.96 Oak 0.60-0.90 Pine 0.35-0.50 Polypropylene 0.91-0.94 PVC 1.39-1.42 Steel 7.9 Substance (Table 3) Density Block Block 1 Substance Block 3 Block 4 Block 5 Block 6 Block 7 Block 8 Block 9 Block 10
Activity 3: Density of Water 8. Determine the density of water: a. Find the mass of an empty graduated cylinder. Record the mass in grams in Table 4. b. Pour 100 ml of water into the graduated cylinder. Try to be as accurate as possible by checking that the meniscus is right at the 100 ml mark. c. Weigh the graduated cylinder with the water in it. Record the mass in grams. d. Find the mass of only the water by subtracting the mass of the empty graduated cylinder. Record the mass of 100 ml of water in the chart below. e. Use the mass and volume of the water to calculate density. Record the density in g/cm3 in the chart. (Hint: 100 ml = 100 cm 3 ) f. Repeat these steps with 50 ml of water. g. Repeat with 25 ml of water. Water Density Chart Mass of Cylinder (g) Mass of Cylinder with Water (g) Mass of Water (g) Volume of Water (ml) Density of Water (g/cm 3 ) 100 50 25 Use the Space Below for any calculations. Then move onto the next page.
9. Plot the mass and volume of water from your chart above on the graph below. Be sure number each axis. Then answer the questions below. 10. As volume increases does the mass of water increase, decrease or remain the same? 11. As volume decreases, does the mass of water increase, decrease or remain the same? 12. Calculate the slope of your line? Show your calculation.
13. Compare the slope of the line to the density of water. Are these two numbers similar or not? 14. What do you think the slope of the line on your graph represents? Activity 4: Sink or Float? 15. Now that you know the densities of the blocks predict which blocks will float in water and which will sink in water. Write your predictions in the table below. 16. Then take only one block at a time and test it at the container of water at the back of the room. Observe whether your block sinks or floats and write what you observe in the table below. Return your block to where you got it from, so that another group can use it. Density Block Prediction (Sink or Float?) Block 1 Observation (Sink or Float?) Block 3 Block 4 Block 5 Block 6 Block 7 Block 8 Block 9 Block 10