Practice Identifying Parts of the Scientific Method

Experimental Scenario #2

A student investigated the effect of radiation on the germination of corn 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 tap water for one hour. They were then divided into three groups. 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. Three days for one week the number of seeds that germinated in each group was recorded; the length of the roots were also measured.

EXPERIMENTAL DESIGN

  1. FOCUS QUESTION: Does radiation affect seed germination?
  2. HYPOTHESIS: If (IV)…then (DV)… statement –

If seeds are microwaved, then there will be (choose: an increase/a decrease/no change) in the number of seeds that germinate and the average root length.

  1. Independent variable – what is changed? amount of microwave radiation exposure
  2. Dependent variable – what is measured and when? # of germinated seeds and root length, on the 1st, 6th, and 8th days
  3. Control – set-up with the most normal conditions 0 seconds of radiation
  4. Constants – everything that is kept the same in each experimental set-up: List all materials except what is changed
  1. MATERIALS: tap water, microwave oven, small beaker, eye-dropper, permanent marker, paper towels, 30 corn seeds, 3 ziploc baggies, soaking time, dates for recording data, temperature, room location
  2. PROCEDURE:
  1. Be detailed regarding numbers of each item, times for each process, etc.
  2. Make a numbered step-by-step list

(1)Gather materials

(2)Soak seeds for one hour in tap water; drain

(3)Label baggies with name, class, number of microwave seconds

(4)Put 10 seeds between layers of paper towel and saturate; put in baggies

(5)Seal 0 seconds of microwave radiation baggie

(6)Microwave the 3 second baggie and 6 second baggie appropriately

(7)Put all in same location

(8)Record data on 1st, 6th, and 8th days

(9)Make graph

(10)Form conclusion

  1. DATA COLLECTION:
  1. Make data table before beginning experiment!
  1. ANALYSIS:
  1. Use data table to make a graph
  1. CONCLUSION:
  1. Review hypothesis, data, and graph
  2. State whether the hypothesis is “supported” or “rejected” and WHY?
  1. PRESENTATION OF INFORMATION

The effects of microwave radiation on corn seed germination

# of seeds that germinated

0 seconds of radiation / 3 seconds of radiation / 6 seconds of radiation
day 1
day 6
day 8
TOTAL

Length of root (mm)

0 seconds of radiation / 3 seconds of radiation / 6 seconds of radiation
day 1
day 6
day 8
TOTAL

Analysis of Experimental Scenarios

– Graphic Organizer –

Problem/Observation:

Question:

Hypothesis:

Experiment:

Procedures

Independent Variable

Dependent Variable

Controls

Control Group

Experimental Group(s)

Results/Data (Graph):

Conclusions: