Example Experiment Question- Does darkness affect germination rate of sunflower seeds? Form your hypothesis and make a prediction. If sunflower seeds are planted in total darkness, then they will germinate.

Designing a Controlled Experiment Must compare between 2 groups Experimental Group- variable is applied Control Group- “Normal” Group

Variables Variables= what you’re testing 2 types Independent Variable= What is changed Dependent Variable= What is measured Must only test 1 independent variable at a time

Control Group Variable is not applied All other things are kept the same as in the variable group

Sample Size Experimental & Control group must be large Larger groups = better experiment

What are the variables? Independent Variable= Amount of light Dependent Variable = germination rate of seeds Must have group of seeds in group in total dark

Control Group This group must be kept in normal day/night conditions Temperature, humidity, acidity of soil, amount of water, planting depth are all controls Only amount of light can be tested- otherwise something else might affect the outcome These must be kept the same in both experimental and control groups

Collecting Data Qualitative- descriptions- color, shape, etc. Quantitative- measurements- time, length, mass, etc.

Other Information Must be able to repeat your experiment If outcome matches your hypothesis, then your hypothesis is supported-not proven If results do not support your hypothesis, what should you do? Re-form your hypothesis and re-experiment