Science Buddies: "Ask an Expert"

My project is the effect of oysters on the water quality of the Chesapeake Bay. In order to test for this i got 4 tanks full of bay water and put about 2 inches of sand in the bottom of each (each tank had equal amounts of sand and water all retrieved from the same place). in the first tank i put 0 oysters, in the second 7 oysters, in the third 14 oysters and in the fourth 21 oysters. I tested for pH, nitrite, ammonia and nitrate for 2 weeks straight testing every other day and then i would start a new trial. I have done 3 trials and i am wondering the best way to graph my results and how to display my raw data. what is raw data? my teacher keeps telling me I need it but i'm not entirely sure I know what she means. So please if you have any suggestions respond to me!
Thanks a bunch!
kelly

What is your teacher telling you to do? It sounds like the best way to graph your data would be a line graph. Plot the pH, etc against a time period (days, etc.) and then look for trends. Microsoft Excel can do this.

thats what she said but i was slightly unsure what I should be graphing. Should I graph all my data from day 1 to day 14 or should I graph an average of all 3 Trials combined? or maybe graph the last day and compare my results at day 14? which one would be best for getting in to the science fair?
thank!

kelly

I would reccomend graphing each trial separately. I also suggest graphing all of your data from day 1 to day 14.

Raw data refers to unprocessed data. The easiest way to show this would be to include a table with all the numbers you recorded. Ideally this table would precede your graphs. As Terik said, graphing each trial separately would probably be best.