Design an experiment—Essay Questions

• Many of the past National AP Biology lab based essay questions have asked students to “Design and experiment to…”
• There are usually some common points in any question of this type. Here are some tips:

Common Points

• Hypothesis- Say the word “hypothesis” and write in the “If…then…” format.
• Example- The hypothesis for this experiment is if higher light allows more photosynthesis, then the plants with the most light should have the most mass.
• Control (or constants)- use the word “control”, but also indicate several variables that are being held constant.
• Example- plants of the same species, from the same seed source, grown in the same soil and under the same conditions.
• Be sure to indicate “which treatment” is serving as the control if you have a separate control group.

Manipulation of the Variable

• Tell how the experiment is manipulated (i.e. what are your treatments). Give a full range of the treatment if possible to avoid the “Three Bears Syndrome” (one too hot, one too cold, one just right)
• Example- The plant will be grown in five treatments of differeing temperatures from 0 degrees to 40 degrees in 10 degree intervals.

Measurements

• Indicate to the reader what is being measured. Use quantitative measurements rather than qualitative.
• Tell when the measurements will be taken.
• Example- The mass of the plants will be taken in grams at the beginning and end of the experiment.

Verification

• Use a large sample size (i.e. the “rule of 10X”) or show that the experiment will be repeated several times.
• Example- There will be 10 plants in each treatment and control group.

Expected Results

• Tell the reader what you expect the results of the experiment to be and explain why.
• Example- The expected results of the experiment is that the plants with more light will have more photosynthesis, therefore, they should have more biomass.

Essay Exam and Quiz Scoring

• Gain points for correct statements.
• No point deduction for wrong answers.
• Must give examples and specific details to gain points. (up to 10 oer question)
• Answers must be in full sentences, not in outline form.
• Drawings permitted, but must be explained

Essay Exam Tips

• Read the question carefully!!!!
• Outline your possible answers, then begin to write.
• Give details and specific examples.
• If question is in parts, write the answer in parts.
• Underline key words or phrases.
• Don't rewrite the question or use the 5 paragraph format.
• NEVER leave an essay question blank. Write definitions to the key words in the question if nothing else.
• Don't assume the writer will "know" what you mean. Give defitions to all terms. (write in parenthesis after the first use of the term in your answer)
• WRITE, WRITE, WRITE!!!!!!!
• Writing the essay exam answers is a learned skill. Expect to get better with each exam.

Essay Exam Tips- if multiple essays on test

• Answer the "easiest" essay question first.
• Spend equal amounts of time on each question.
• Don't refer reader to answer written in another question.