1. EOC Review!!! Suki and Alex live near Pipe Lake. They are concerned that increasing carbon dioxide levels in the atmosphere are impacting the lake. As part of a monitoring program they are provided the following materials: -pure water-seltzer water -beakers -BTB solution -samples of Pipe Lake water (taken every year for the last ten years)

2. Describe a simple test (or tests) that Suki and Alex could do to determine whether or not the lake is being impacted. – Be sure to include the form or forms carbon can take. – Make sure the experiment accounts for all variables and will guarantee a valid conclusion. – Describe the type of results that would cause Suki and Alex to be concerned about the health of Pipe Lake. MAKE SURE YOU ADDRESS EACH AND EVERY BULLET POINT!!

3. Make sure you address EACH and EVERY bullet point!! “Be sure to include the form or forms carbon can take.” In this scenario the forms of carbon are CO 2 gas (in the atmosphere) and carbonic acid H 2 CO 3 (formed when CO 2 dissolves in the lake)

4. Make sure you address EACH and EVERY bullet point!! “Make sure the experiment accounts for all variables and will guarantee a valid conclusion.” Things to include/identify in this part of your answer: manipulated variable responding variable controlled variables (LOTS of these!!) validity measure repeated trials

5. Make sure you address EACH and EVERY bullet point!! “Make sure the experiment accounts for all variables and will guarantee a valid conclusion.” Put 10 mL of seltzer water in a clean 100 mL beaker. Put 10 mL of distilled water in a clean 100 mL beaker. Put 10 mL of each of the 10 lake water samples in separate clean 100 mL beakers. Label the beakers. Add 5 drops of BTB solution to each beaker and swirl to mix. Can you identify 3 controlled variables? Can you identify a validity measure?

6. Make sure you address EACH and EVERY bullet point!! “Make sure the experiment accounts for all variables and will guarantee a valid conclusion.” BTB + seltzer water will turn yellow. This is your comparison for an acidic solution. (serves as the experimental control) BTB + pure water will turn blue. This is your comparison for a slightly basic solution (serves as another experimental control)

7. Make sure you address EACH and EVERY bullet point!! “Make sure the experiment accounts for all variables and will guarantee a valid conclusion.” Compare the colors of the lake water samples to your experimental controls. If the samples are becoming more like the seltzer water experimental control (more towards yellow) then Pipe Lake is becoming more acidic as the years pass. If the lake water samples are more like the pure water experimental control, then Pipe Lake is not becoming more acidic as the years pass.

8. Make sure you address EACH and EVERY bullet point!! “Make sure the experiment accounts for all variables and will guarantee a valid conclusion.” Clean out ALL your glassware and REPEAT the entire experiment. Cleaning your glassware is a VALIDITY MEASURE. Repeating increases the RELIABILITY of your data.

9. Make sure you address EACH and EVERY bullet point!! “Describe the type of results that would cause Suki and Alex to be concerned about the health of Pipe Lake.” The results below indicate that Pipe Lake IS becoming more acidic. This is a concern because small organisms such as phytoplankton might be impacted by the increased acidity. This could disrupt the food chain in Pipe Lake. seltzer H 2 O year: 10 5 2 pure H20