SURVEY OF CHEMISTRY LABORATORY I

CHEM 1151L

BLUE BOTTLETHE HYPOTHESIS CYCLE

CAUTION!!!CAUTION!!!BE SURE TO WEAR SAFETY GLASSES AT

ALLTIMES IN THE LABORATORY

NO EXCEPTIONS TO THIS RULE!

- To access students’ critical thinking skills

- To access students’ ability to communicate in writing

- Students will design and carry out a variety of experiments

to discover the cause(s) of changes observed

BLUE BOTTLE

SOLUTIONS FOR BLUE BOTTLE

- Obtain a clean 125 mL Erlenmeyer flask

MIX SOLUTIONS

Mix in the flask

- 25 mL of solution A

- 25 mL of solution B

- Four drops of solution C

MIX SOLUTIONS

- Place a rubber stopper firmly on the flask

- Shake the contents vigorously

MAKE OBSERVATIONS

- Set the flask down

- Watch for a few minutes

- Record any observations made

MAKE OBSERVATIONS

- Shake the flask again

- Make observations again

MAKE OBSERVATIONS

- List the major goal of this exercise

- Break the major goal into two minor goals that can be investigated

DESIGN EXPERIMENTS

For each of the minor goals

- Write a testable hypothesis

- Design an experiment to test the hypothesis

- Consult instructor for approval

- Carry out the experiment

DESIGN EXPERIMENTS

DESIGN EXPERIMENTS

A number of laboratory materials are available

- Litmus paper

- Ice

- Warm temperature bath

- Nitrogen gas

- Oxygen gas

- Buret

- ETC

For each of the minor goals

- Record observations

- Draw conclusions

- Write a restructured hypothesis

- Repeat the cycle until the goals are accomplished

DESIGN EXPERIMENTS

- Synthesize your conclusions into a coherent explanations of the major goal

DESIGN EXPERIMENTS

Write a formal laboratory report that includes the following elements

- An introduction to the overall goal of the work- A statement of your initial observations

- A statement of the first hypothesis developed- A description of the experiment designed to test the hypothesis

- A clear description of the result of that experiment- The conclusion drawn from the experiment

- Repeat Steps 3 – 6 for each hypothesis developed- An overall summary of all the experiments

- The final conclusion

WRITTEN REPORT