Materials Needed

plastic tray or plate, plastic wrap
paper towel, water
package of radish seeds
microwave oven
ruler, pencil, graph paper

General Laboratory Question

What is the effect of increasing exposure times of microwave radiation on radish seed germination? What is the effect of increasing exposure times of microwave radiation on radish seed sprout length?

Part 1.

Form a hypothesis

1. Consider the questions above.
2. Write a hypothesis (prediction)for each question, in the below space.
3. Make sure they are clear and testable!
Use the If(statement about observations)…then (prediction of results of experiment)… format.
For instance, If I drop a pencil, then it will fall.

Part 2.

Procedure to test hypothesis
1. Prepare six plastic germination chambers by folding the paper towel into the bottom of a plate, pan or tray and moisten the paper towel in each chamber.
2.Separate the radish seeds in the package into 6 groups of at least ten (10) intact seeds in each group. Place each group of seeds into the microwave oven for a different amount of time. Use times of 0 sec, 10 sec, 20 sec 40 sec, 80 sec and 120 sec.
3. Place each group in a separate chamber and write the length of time the seeds were exposed to microwave radiation on the plastic chamber. Also write down the date of the beginning of the experiment.
4. Cover the seeds and the moistened paper towel to keep in the moisture during the next 6 days. You may need to add a few drops of water if the towel gets dry during the experiment.
5. Store the plastic plates where they will not be disturbed, but in the light.

Answer the following questions for this experimental setting.
1. What is the independent variable?
2. What is the dependent variable?
3. Which of the groups of seeds would be the control group for this experiment?

Part 3.

Results of test.
1. Observe the radish seeds in your plastic dish daily for a “sprout” or leaflets coming out of the seed. Note: there may also be fine, white hairlike rootlets-ignore those.
2. On the sixth day you are to COUNT the number of seeds that you can see the “sprout” coming out of the seed–even if the sprout is very small. Don’t count them if the outside coat of the seed has broken open but there is no “sprout.”
3. RECORD the number of seeds germinated for each group on the sixth day. CALCULATE the average percent of seeds that germinated by the sixth day for each exposure time.
PRODUCE a table with the percentage data and REPORT that information below.

Part 4.

Results continued.
4. MEASURE the length of the sprouts, in millimeters (mm), for each sprouted seed for each group on the sixth day. CALCULATE average sprout length for each time exposure. Make sure you identify the mm marks on the ruler- there are 25 mm in an inch and a mm is about the
width of a period (.)
5. PRODUCE a table of the data and REPORT that data below.

Part 5.

Reporting and plotting  the data.
1.Click here to REPORT both of your germination and sprout information so all laboratory participants can observe your data.
We will soon be discussing all of the data, from all participants, on the bulletin board.
2. On a separate piece of blank, white graph paper, construct two XY graphs (see Figure 8.20C in textbook for example) of your data: one that compares the average percent of seeds that germinated to exposure time and another that compares sprout lenght to exposure time.
Convention dictates that you label the horizontal or X axis as the independent variable and the vertical or Y axis as the dependent variable. Make sure you use label both axes with relevant numbers and label each graph .
3. Print and sign your name on the graphs and then FAX both the graphs to the instructor.
Please write boldly so the FAX will be legible.
Neatness counts!

Part 6.

Discussing the data.
4. In the space below, indicate if the data supports or does not support your prediction (hypothesis).
5. Using your data, discuss your conclusions concerning the effect of microwave exposure on:
1)germination rates and 2)sprout lengths.