Practice+Scenario

Seed Germination and Radiation

A student investigated the effect of radiation on the germination of bean seeds. He __thought that exposure to radiation would limit the seeds ability to germinate (grow)__ much like ultra-violet light causing skin cancer. __Three hundred seeds__ were __soaked in water__ for __one hour__. They were then divided into __three groups of 100 beans each__. __One group__ was placed in a __microwave__ __ * __ __oven on high for three seconds__. __Another group was microwaved on high for six seconds__. The __last group was not microwaved__. The seeds were then __planted__ in __three separate flats__ and given the __same amount of water__. The flats were placed in a location with a __constant temperature__ of approximately __27 degrees Celsius__. __Each day__ for __two weeks__ the __number__ of __seeds__ that __germinated__ e__ach group was recorded__. The results of his experiment are noted below: *Note: microwaving the seeds exposes them to radiation
 * = Length of exposure ||= 3 seconds of radiation ||= 6 seconds of radiation ||= No radiation ||
 * = # Germinating seeds || 54 seeds ||= 26 seeds ||= 88 seeds ||

Complete each of the following:
 * 1) Identify the student's hypothesis: ** If seeds are exposed to radiation then seed germination will be decreased. **
 * 2) Identify the independent variable: ** amount of radiation **
 * 3) Identify the dependent variable: ** seed growth or germination **
 * 4) Identify the other variables the student needs to consider/control during this experiment: ** soil (type, amount), fertilizer (concentration, type), amount of sunlight, temperature, presence of pests, type of bean, age of seeds, temperature of water (soaked, and applied), time of planting, range of experiment, how much water **
 * 5) Identify the control group in this experiment: ** beans without radiation **
 * 6) Identify the experimental group: ** two groups of seeds exposed to radiation **
 * 7) What conclusions might the student draw from this data? ** More seeds germinate when not exposed to radiation; increased radiation yields a decrease in germination - hypothesis was supported **
 * 8) What recommendations might you suggest for further study or for improvement? ** try more radiation, different species of beans or even different seeds **