BI101 Unit 1 Experiment

WEEK 1 EXPERIMENT ANSWER SHEET Please submit to the Week 1 Experiment dropbox no later than Sunday midnight.

SUMMARY OF ACTIVITIES FOR WEEK 1 EXPERIMENT ASSIGNMENT

· Experiment 1 Exercise 1 – The Scientific Method

· Experiment 1 Exercise 2A – pH of Common Solutions

· Experiment 1 Exercise 2B -- pH and Buffers

Experiment 1 Exercise 1: The Scientific Method

After viewing following video, answer the questions that follow:

Bowers, N. 2013. Scientific Method Exercise http://www.youtube.com/watch?v=8S7N_1xnYEE&feature=youtu.be

1. Write out four biological observations you made as you watched the video. Be specific about what you saw. These observations might deal with the habitat, season, flora, fauna, behaviors and interactions (2 pts).

2. Choose one or two of the observations above and write two questions you have regarding what you observed (2 pts).

3. Based on your observations or questions write two possible hypotheses that might explain your observation and/or answer your question (2 pts).

4. Write one prediction based on each hypothesis listed in Q#3 (2 pts).

5. What additional information might you need in order to design and conduct an experiment to test that one of your hypotheses (2 pts)?

Experiment 1 Exercise 2A: pH of Common Solutions

Be sure that you have completed your text book readings, have read through the online lecture and have read the introductory material for the Week 1 Experiment before starting. First, answer the following questions:

Questions

1. What is the definition of an acid? Your definition should include more than just a pH range. Provide one example of an acid. Cite your sources. (2 pts).

2. What is the definition of a base? Your definition should include more than just a pH range. Provide one example of a base. Cite your sources. (2 pts).

Procedure

A. Using your textbook, online lecture or other source, fill in Table 1 below. Be sure to complete your predictions BEFORE you look up the actual pH values.

B. Be sure to provide complete citations for the sources used to determine the actual pH values.

Table 1. Predicted and actual pH values and your explanations. You are only required to complete the first six; the others are optional. Use your textbook, online lecture or other source to determine the actual pH values (6 pts).

	Substance	Predicted pH	Explanation for Prediction	Actual pH
1	Lemon juice
2	Stomach acid
3	Oven cleaner
4	Antacid
5	Pure water
6	Orange juice
Optional additional solutions
7	Sea water
8	Vinegar
9	Shampoo
10	Soft drinks
11	Tomatoes
12	Battery acid

Questions

1. Which of your substances tested are considered an acid (1 pts)?

2. Which of your substances tested are considered a base (1 pts)?

3. What surprised you most about your results in this activity (1 pts)?

Experiment 1 Exercise 2B: Buffers

Before beginning, answer the following question:

Question

1. What is a buffer and briefly, how do they work? Cite your source (2 pts)?

Procedure

Watch the following simulation and answer the questions after watching.

https://www.youtube.com/watch?v=ZLKEjXbCU30

Questions

2. Why does the green bar in the graph drop? Why does the purple bar in the graph rise? Explain what is occurring chemically (4 pts).

3. In the simulation shown, what happens to the pH in the beaker when HCl is added? How do you know this based on what you see in the graph (2 pts)?

4. What will happen to the pH if HCl is added after all of the acetate is used up? (1 pts)?

5. What is formed when sodium hydroxide is added and how does this affect the pH (4 pts)?

Week 1 Experiment Grading Rubric

Component	Expectation	Points
Experiment 1 Exercise 1	Demonstrates an understanding of the Scientific Method and an ability to apply it (Table 1, Questions 1-3)	10 pts
Experiment 1 Exercise 2A	Demonstrates an understanding of pH and how it applies to your everyday life (Table 2, Questions 1-5).	13 pts
Experiment 1 Exercise 2B	Demonstrates an understanding of pH and the effect of buffers (Questions 1-5)	13 pts
TOTAL		36 pts