Experimental Design Coaches’ Clinic Fall 2011
Experimental Design requires three students who appreciate the challenge of designing, conducting and reporting a quick experiment. This is not a technical event. It requires scientific literacy and verbal facility. Students who struggle with English will struggle in this event.
1. TEAM SELECTION: Select a team that can COMMUNICATE, knows experiments, works with SPEED, can write well, can SPELL even better, and gets along with each other. The chemistry of the individuals is important.
Teams need to PRACTICE together and decide in advance who does what well. This should involve MASTERY of the terms, discussion of technique and brainstorming practice. In advance the team should realize that one person can be testing, another recording data and the third person can be working on the write-up.
2. BRING EQUIPMENT: ruler, timepiece and non-programmable calculator. This is a mathematical event. Other equipment: safety goggles, lab apron/lab coat.
3. The experiment does not have to be based on a valid scientific principle—it does have to prove or disprove a hypothesis. There is no grading that rewards scientific knowledge outside of the experimental design format.
4. SCORING WELL: Students must have a grasp of the terms. They have to do 3 trials (preferably) of their experiment to generate the data for their graph. A sketch is an imperative. Some portions can be started even before the experiment is completed.
5. SIMPLICITY: This event is not about technical measuring, ridiculous statistics, or calculator abuse…. It is about a good hypothesis, testing, writing accurately but briefly, and completing the task as directed.
Experimental Design Rubric
1. Statement (2 points): what will be investigated, 3-4 sentences
2. Hypothesis (4 points): testable prediction, predicts the relationship between the independent and dependent variable
3. Variables Constants (4 points) those variables that are identical in the set-up
Independent (3 points) factor being manipulated, tested, changed
Dependent (3 points) factor that responds to the independent variable,
also known as data
4. Experimental control(Standard of comparison) (2 points) the component in which the independent variable is not changed. Is what is happening a result of the independent variable or would it happen anyhow?? It is more useful in biological/medical experiments. New this year: “where applicable” has been added to the write-up so it may not be included.
5. Materials (3 points) a list is sufficient
6. Procedure (6 points) A step-by-step description of what was done. A DIAGRAM IS VERY NECESSARY—in case students are not articulate.
7. Qualitative observations and summary of results (4 points) Description of what happened in the course of experiment.
8. Data table (6 points): numerical results from 3 trials
9. Graph (6 points): bar or line graph
10. Statistics (2 points B; 4 points C): average, median, mode, range, line of best-fit, mean, etc.
11. Analysis of results (4 points): evaluate the data presented, interpretation, go back to original hypothesis, whether it was proven or incorrect, solid thinking required here
12. Possible exptal errors (3 points): experimental mistakes, problems with equipment or technique, IDENTIFIED human errors
13. Conclusion (4 points): Summarize what was done and whether the problem was solved as originally planned—or not. This is a succinct version of # 11 with reference to the original hypothesis and experimental design.
14. Recommendations for further experimentation, practical applications (4 points): possible modifications of design or procedure, other experiments that might be interesting and why, possible practical uses of experiment, technique, data
Although it seems like a given, students must adhere to good safety principles, respect for the lab space they are working in and returning materials to supervisors as they are asked. We make clean-up part of the routine and grounds for disqualification if not done properly.
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Topic areas that present good experiments that can be completed in 50 minutes
Solubility, pH, elasticity, temperature, absorption, static electricity, packing ratios (how much air is in a given volume of sand, gravel, marbles), laws of motion, paper airplane design/flying, electromagnets, parachutes
Experiment done with very little set-up: 3 sheets of paper, ruler, golf ball and brown lunch bag. Experiment—roll golf ball down ramp into bag. Begin with 22 1/2o angle made possible by folding the paper, then a ramp that was 45o and finally 67 1/2o –have golf ball go into bag at the bottom of the ramp—distance the bag travels varies with the angle of the ramp.
Example of a state experimental design: given an ocean sponge, household sponge, pumice and towel piece, investigate (compare/contrast) the physical properties of these materials including porosity, capacity, permeability, wetability, or specific gravity.
Example of experimental design(national 2009) given several fabric squares—silk, rayon, polyester, nylon, cotton, glass rod, straws, various small objects to be attracted(Styrofoam, balloons, small paper clips), investigate static electricity…
Warn your students that textbook authors often give their own version of the vocabulary that is used in experimental write-ups. It can be confusing (starting with our own control variable….) and students should concentrate in the weeks before competition exactly what is expected. Many errors result from not understanding exactly what belongs in each section.
If your science team has very specific rules about write-up’s that are different from experimental design, please emphasize these to your team. There are often quirky, inexplicable aspects to a write-up and a grader will note that this is THE RULE at their school.
EVENT SUPERVISORS
If you are running this event, your biggest challenge is developing a problem, task or premise that is interesting, feasible, works in the space provided for the event and hopefully has more than one experimental avenue. The problem should permit students to go in different directions so that you are not reading the same report 15 or 18 times. Look at junior high lab manuals but go outside the usual format. For high school complicate the same lab: use a table, set of information, or more challenging approach.
Before you settle on a topic, test your premise with different experiments. Make sure your equipment works well. Pretest extensively if your idea is at all complicated. At invitationals and regionals, a simple problem is best. Have the write-up reading to go with appropriate points for each subtopic. If you have more than 12-15 teams, double the points to avoid excessive decimals when breaking ties. Put equipment is a brown lunch bag; regular lab equipment will not give anything away.
Day of competition: place teams as far away from one another as possible. Allow supervision from the front and back of the room. Watch carefully the first round and duplicate that experience with your second group. Put a post-it on the lab space and have teams put their number on it. Always have 1-2 extra set-ups ready to go. Give initial instructions and then challenge them to begin talking as soon as you finish. A quiet experimental design competition will yield very boring lab reports. Check names, school and number at the beginning and when they turn them in.
Grading: have the same person grade the same pages. If you have two graders, have one person do the first three pages, the other the second two. As you complete a report, lay it out in numerical order. Break ties according to the rules.
Concerns about faking, fudging, dry labbing, and fabricating
Emphasize to students the importance of ethical experimentation. It is against the code of the Science Olympiad to pretend to do this event. Students think that they are much more clever and can disguise their laziness but it is often quite apparent. Examples are implausible data, astounding amounts of data or an experiment that cannot be done with materials provided. Having some sections prepared in advance is also obvious. Please discourage students from anticipating the event in this way.