Science Buddies: "Ask an Expert"

I just wrapped up my experiment on how sodium hypochlorite affects the time it takes lima beans to germenate. As soon as I saw the seeds had germenated, I stopped the experiment. I watered the beans with various mixtures of water and sodium hypochlorite for each different group of seeds. (100% sodium hypochlorite with 0% water, 75% sodium hypochlorite with 25% water, 50% sodium hypochlorite with 50% water, 25% sodium hypochlorite with 75% water, and 0% sodium hypochlorite with 100% water) Only the seeds watered with 0% SH germenated. I really don't know how to organize my data or what type of graph to use, as I only checked up on the seeds once a day . Please help!!

Here is my log, if it's of any use:

December 13, 2010-
Seeds were put into plastic bags, sprayed with appropriate solutions, and left out in sun.
December 14, 2010-
No noticeable change.
December 15, 2010-
No noticeable change.
December 16, 2010-
The seed coat of the seeds in the 100% Sodium Hypochlorite group appears to be shrinking.
December 17, 2010-
All of the seed coats of the seeds in the 100 %, 75%, 50% and 25% groups appear to be shrinking.
December 18, 2010-
0% B has germinated
0% C is partially covered in a yellow powder.
December 19, 2010-
0% E has germinated.
100% A has split open.
December 20, 2010-
0% A and 0% D have germinated.

Thanks!

Your graph will represent your measurements over time. Usually time is placed on the X (horizontal) axis and the measured variable on the Y axis. So you would graph "% germinated" (Y) versus time (X). The unit of time, as you indicate, is one day.

So you would show 0 to 100% Germinated on the Y axis and 1 to 7 (or 1 to 10) days on the X axis (the X axis might be labeled "Number of days since planting").

Your independent variable is the percentage of Sodium Hypochlorite solution. If you use a bar graph format, there will be one "% germinated" bar (column) for each solution you tested. This means that there will be four bars for each day, corresponding to the four solutions. Each bar would be a different color or pattern. You would accompany the graph with a key indicating what the colors/patterns mean.

Given your results, your bar graph will very simple -- there will be four bars at zero (i.e., they will just show as colored lines on the X axis) for every day until we come to the sixth day. Then, we will see three bars still at zero and the fourth bar will be at 100%.

As you probably realize, this graph doesn't make the results clearer -- it's just as easy to understand a verbal summary, "All of the seeds watered with 0% SH germinated on the sixth day; none of the seeds in the other solutions germinated."

If you are writing a report, you would also indicate why you stopped the experiment after a week. How did you know that the other seeds would never germinate?

Please let me know if I you have any questions about my suggestions.

Bill

You may also want to include a graphic image depicting the different seeds at a given day. Perhaps a drawing in colored pencil? Just a suggestion.