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U1C1A4. Evaluating Experimental Design. Exp 1: Heating Earth Materials. 1Q: If the type of Earth’s material is changed, what happens to the temperature of the material as it is heated by sunlight?. 2. MV: type of Earth materials
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U1C1A4 Evaluating Experimental Design
Exp 1: Heating Earth Materials • 1Q: If the type of Earth’s material is changed, what happens to the temperature of the material as it is heated by sunlight?
2. MV: type of Earth materials • RV: temperature of Earth materials as heated by sunlight
4. RV is measured in temperature, Degrees C, with a thermometer
5. Same: buckets, amount of sunlight, thermometers and their placement, time in the sun
6. Differences other than MV and RV: • Yes, the amount of Earth material • Full bucket soil, 1/2 bucket water
7. No, this is not a fair test - more than one variable - see answer to #6. • (amount of Earth material varies)
Exp 2: Freezing Water • 1Q: If hot and cold water are placed in a freezer, which freezes more quickly?
2. MV: water temperature • RV: time it takes for water to freeze
4. RV measured by time intervals, and observing if water frozen
5. Same/control: • tray size • amount of water added in each tray • liquid used is water • 15 minute interval checks • both put in the same freezer
6. Different other than MV and RV: Yes. • The trays are made out of different material (metal, plastic), and they are place on different shelves in the freezer • (top, bottom)
7. This experiment is NOT a fair test because of #6, more than one variable (tray material and location).
Exp 3: Corn • 1Q: If the type of corn seed is changed, what happens to its growth rate and health in crowded conditions?
2. MV: type of corn seed • RV: growth rate and health
4. RV measured by observation of the plant health, and measurement/count of growth
5. Same/control: • same number of seeds in each pot, same pot sizes • same depth planted • same amount of water • all checked at same time (3 weeks)
6. Different other than MV and RV: Yes, the type of soil in each pot is different
7. No this is not a fair experiment, because there is more than 1 variable (soil type)
Conclusion: You should be able to answer/identify the 7 criteria used in this activity to determine if an experiment is designed fairly: • 1Q • 2: MV, RV • 3: values MV • 4. RV measurement • 5. Same controls • 6. Different variables • 7. Answer (Fair, yes or no)
Share/Communicate: • See the “How to Analyze an Experimental Design and determine if the Experiment is a Fair test”