Practice+Scenario+pd+7

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 wate__r. 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 each 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: ** exposure to radiation will limit seeds ability to germinate **
 * 2) Identify the independent variable: ** the amount of radiation seeds are exposed to **
 * 3) Identify the dependent variable: ** seeds ability to germinate **
 * 4) Identify the other variables the student needs to consider/control during this experiment: ** all be the same type of bean seed, same amount of water, temperature of water, seed storage, size of the planting flat/pot, seed conditions, same climate, type of soil, amount of soil, brand of beans, **
 * 5) Identify the control group in this experiment: ** group of seeds not microwaved (exposed to radiation) **
 * 6) Identify the experimental group: ** seeds that are microwaved one group for 3 sec and one group for 6 sec **
 * 7) What conclusions might the student draw from this data? ** seeds without radiation germinate better than the seeds that were exposed to radiation (hypothesis was correct) as 88/100 seeds germinated with zero radiation while 54/100 and 26/100 germinated with 3 seconds and 6 seconds. An increase in radiation caused a decrease in germination. **
 * 8) What recommendations might you suggest for further study or for improvement? ** ensure all of the variables identified in #4 above are held constant not just soaking time, amount of water, and temperature of growing environment; try the experiment on another type of seed instead of bean seed (pumpkin, marigold, radish, etc) to make sure it isn't just something that happens with bean seeds. **