posted by peter .
I did this experiment and I found these validity issues: they never specified if temperature to be measured in celcius or faren., they never mentioned that the buckets were to be the same, stirring until your arms get tired is not a good idea, but I need three more validity issues?????
DO you consider the companys conclusion valid? How could them improve?
To prevent future brownfield sites the DEP's concer lies in the fact that the chemical in the wastewater eventually reaches natural waterways and affects drinking water. It decided to test the temperatureeffects of a chemial to the natural water that could be contaminating.
Their experiment was based on this statement: We are trying to determine if adding chamiall X to stream water causes the stream water to rise in temperature.
HEre is the procedure:
1. Take two buckets and fill each one about halfway with tap water.
2. Record the temperature of each bucket of water.
3. Put a shovel full of chemical into bucket number 1 and stir until arms get tired. Record the temperature.
4. Put 2 shovel fulls in bucket number two and record temperature.
So it again for accurate results.
Graph and make conclusion
In one bucket the temperature increased from 15 to 35 degrees and in the other bucket the temperature increased from 15 to 37 degrees. They concluded the chemical was responsible for temperature rise.
In 1, not only do they not specify the size of the buckets BUT they also say "FILL ABOUT HALFWAY WITH TAP WATER." The exact amount of water should be stated. Second, is tap water the same as "stream water."
In 2. T in C or F you have.
In 3. A shovel full of chemical is not precise enough. The researcher should specify the amount of chemical added. The researcher should specify over what period of time the chemical is added. Also, a specific amount of time should be given. Stirring until arms get tired is not good enough since that would vary depending upon whose arms we were using.
I would add one more to the steps above. Since the initial statement was that they were trying to determine if chemical X caused a rise in the termperature of stream water, my answer would be, "So what?" Whether the chemical raises the temperature of stream water has nothing to do with the wastewater eventually reaching streams. Why? One could argue that even if adding a chemical to waste water raised the temperature of the wastewater, letting that wastewater cool ( in air) before dumping it into a stream would not raise the temperature of the stream. My point in the last argument is that this experiment will NOT tell them anything they want to know.