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back Task A: __Define the Problem __ The first task is to determine what four blocks are made of based on their density. So the problem is to determine what material four different blocks are made of. (Tell what you are trying to determine.)

__Procedure __ The density of the four blocks must be measured to determine what they are made of. Density is mass divided by volume, so both the mass and volumes of the blocks must be measured. A scale must be used to measure how many grams each block weighs in grams. The formula for finding the volume of a block is length x width x height. The sides of each block must be measured with a ruler in centimeters and then their volumes are calculated. Once the mass and volume has been determined for each block their densities are calculated as indicated above. The description, mass, volume, and density for each block is recorded in a data table. Listing the step used in the process to calculate density is a good way to explain the procedure used. (Measure the mass and volume of four blocks. Divide these masses by their volumes to get the blocks’ densities.)

__Analyzing the Data __ Data will be analyzed by comparing the densities calculated for each block to densities of a few similar known materials. Each block should be made of the substance with the density closest to the density that the student calculated for the block. (Compare the density of the block to density of other similar substances.)

__Conclusion __ Conclusions are made by stating which block is made of which substance. For example, the grey stony block has a density of 2.3 and concrete has a density of 2.4, so the gray stony block made of concrete. (State a conclusion for each block, citing your data and the density of a known substance.)

Task B: __<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Define the Problem __ <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Four tubes must be sorted into two pairs by density.

__<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Procedure __ <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">The density of each tube must be measured. Density is mass divided by volume, so the mass and volume of each tube must be measured. The masses of each tube will be measured in grams using a balance. The volume of each tube will be measured in centimeters using a ruler. The volume of a cylinder is base times height. The area of the circular base is calculated with the formula 3.14( <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 14pt;">r2 <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">). Once the mass and volume of each tube is measured, each tube’s density can be calculated as indicated above. These masses, volumes and densities should be recorded in a data table. Listing the steps used to determine the density of each tube is a good way to explain how each tube’s density was determined.

__<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Analyze the data __ <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">The density of the four tubes will be compared to sort them by density. The two pairs of tubes with similar densities will be noted. A graph with two straight lines starting at zero can be used to analyze the data. First the four densities should be plotted on the graph. Then one line should be drawn from the zero towards two of the densities. The other line should be drawn from the zero towards the other two densities. The pair of dots closets to each line have the closest calculated densities.

__<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Make a conclusion __ <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Tell how the tubes pair-up citing the closeness of their densities.

<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Task C: <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Use your write-up for task A and B as a model to write-up task C. Make sure you have done as good as job as possible on Task A & B before starting task C.

<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Other related info: <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">Does an ice cube melt faster in fresh or salt water. <span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 11pt;">How might density differences between freshwater and saltwater influence ocean currents.

https://www.calacademy.org/educators/lesson-plans/differing-densities-fresh-and-salt-water

https://van.physics.illinois.edu/qa/listing.php?id=1662 http://mirjamglessmer.com/2013/09/04/ice-cubes-melting-in-fresh-water-and-salt-water-post-24/