Designing an Experiment Unit 1 Designing an Experiment

(1) State the Question What do you want to know? (Problem) What is the effect of ________________ on ________________? Independent variable Dependent variable

Problem Which brand of microwave popcorn pops the most kernels per bag? IV/MV: Brands of popcorn DV/RV: Number of kernels that popped

(2) Make a hypothesis A prediction of the experiment’s outcome Written as an “If…then…” statement. If IV/MV is action Then DV/RV is action Example: Hypothesis: IF 4 different brands of popcorn are popped, THEN Movie Time popcorn will pop Prediction Prediction the most kernels per bag

(3) Design the experiment Materials – list of things you need to perform the experiment Procedure – Numbered list of steps you take to perform the experiment

Design the Experiment Materials List 4 brands of microwave popcorn Bowl Data table Procedure Buy 4 different brands of microwave popcorn Pop 1st bag of popcorn Count number of kernels popped Record Data into data table

(4) Make observations Record data Use appropriate metric units as needed Ex: Record Data into data table Brands Trial 1 Trial 2 Trial 3 Average Store Brand 234 236 225 232 Orville Reden 330 335 328 331 Movie Time 285 278 281 Jiffy Pop 258 250 248 252

(5) Study results Shown as graphs – make graph from data table 1. Bar Graph 2. Line Graph 3. Pie Chart

(6) conclusion Describes the purpose and the results of the experiment. 3 steps to the conclusion Ex: 1 Answer the ? asked in the problem 2. Restate hypothesis and state if it is correct or incorrect 3. Use the data from data table to support your conclusion

Conclusion The brand of microwave popcorn that popped the most kernels per bag was Orville Redenbacher. The hypothesis was incorrect. It stated that Movie Time brand would pop the most kernels per bag, but the data table showed that Orville Redenbacher popped 331 kernels and Movie Time popped 281 kernels.

Parts of an Experiment

(8) control Used as a comparison Unchanged/Natural/Original Ex: The store brand of microwave popcorn

Experimental Group The group that is changed or tested Ex: The 3 national brands of microwave popcorn

(7) Independent variable I change the independent variable. Also called the manipulated variable Each experiment should only test ONE I.V. (MV) Ex: The 4 different brands of microwave popcorn

= = Independent variable Changing the brands of Microwave popcorn Changing One variable Changing the brands of popcorn and the time it cooks = Changing too many variables

(9) Dependent variable This is what the IV (MV) effects. This is what you measure/collect data from Ex: The number of kernels that popped

(10) constants Factors that stay the same in an experiment. There are MANY in an experiment. Examples: Same microwave Same amount of popcorn per bag by weight Cook for the same amount of time

(11) trials More trials = More reliable results. Ex: pop 3 bags of each brand to ensure more reliable results