Lab Report Summary and Conclusion

The purpose of this lab was to separate the beads (yellow, blue, gray, and clear) by their densities.  We did this by adding more or less salt water to the beaker, then pouring the beads into the water and seeing which one floated on top. 

Our first trial was freshwater. We poured all the beads into the beaker, and found that the gray colored beads floated while the others sank to the bottom.  We fished the gray beads out of the water and found their mass was 2.6g out of 10.5g.  This gave us a percent composition of 24.7%

Our next trial was mostly salt water, but due to some difficulties, there was some freshwater in the salt solution.  We found that both  the blue and the yellow beads would float, so we decded to dilute the mixture to be approximately half freshwater and half salt water.  When we did this, the blue still floated on the surface, while the yellow sank down to the middle, and the clear beads stayed on the bottom.  Once again, we collected the blue beads out of the water and found that the blue beads had a mass of 4.0g out of 10.5g.  This gave us a percent composition of 38%

Our last trial was purely salt water.  During this trial, the yellow beads floated back to the surface of the solution, while the clear beads stayed on the bottom.  We collected the yellow beads and the clear beads.  We then measured them separately.  The yellow beads had a mass of 10.9 out of 10.5.  This is obviously wrong, but it gave us a percent composition of 103%.  The clear beads had a mass of 9.91g out of 10.5.  We got a percent composition of 94.3%.

In conclusion, by looking at this data obviously something went wrong.  The sum of the percents is over 100%, and sum of the masses of the beads do not equal 10.5g.  I think that one thing that went wrong was that we were not exactly precise about the amount of water used.  I think if we kept track of how much of the salt solution and how much of the freshwater we used, we would have had results that were more accurate.  I think that finding the mass of the beads while they were still wet definitely affected the mass of the beads, especially the beads we weighed after putting them in salt water.  Salt water is more dense, so it probably affected the mass moreso than the freshwater.  Either way, both the freshwater and the salt solution affected the mass of the beads.  We should have dried the beads before finding the mass.  I think a way we can improve this experiment is to add another color of beads.  Another way we could do this is to maybe test the beads in another type of solution, not including testing the beads in salt solution and freshwater.