Isaac Nelson
Ms. Bredeweg
Biology Two
29 November, 2012
Experimental Design Diagram
- Question: Does distance from a source of water determine which tree will have it’s leave stay green longer?
- Hypothesis: If a tree is closer to the stream, then it’s leaves will stay green longer because it will have more nutrition from the water.
- Controlled Variables: Amount of time between visits, Type of tree, Size of tree, time of day taken, Base color used to find data
- Independent Variable: Distance from stream
- Materials Needed: Camera, Daylight, Proper footwear, Computer equipped with Adobe Photoshop
- Procedure: First, make sure a week has passed since the last visit. Secondly, wear tennis shoes or boots. Next, walk to the research location in daylight. Find the first tree marked with an orange ribbon (it should be on the very edge of the creek). Observe the color of the leaves, and take two photographs: The first of one branch’s leaves, and the second of the tree in it’s entirety. Continue approximately nine yards back from the water to the next marked tree. Repeat the process for that tree and the two that follow. Find a color that is consistent in the leaves in every one of your photos. This will be your base color. Take these eight photos and add them to your computer. Open them in Photoshop. Go to Photoshop preferences in the top left and Guides, Grids, Slices, etc. Make your color grid black with a gridline every tenth of the way across the picture. Set subdivisions to one. Click on View, then Show Grid. The picture will now have a grid on it. Use this to look for how many sections have the base color you gathered in your first visit. Repeat one week from your visit until time is up or there is no longer any of your base color left in any of the trees.
- Procedural Example: This is a photograph of one of the sets leaves in question, and a photo of the base color used for measuring. Here, you can see that in Photoshop a grid has been placed over it. From this one can deduce an approximate amount of the base color left in a leaf.
- Data Table
- Graph
- Graph Key: Y axis: time, X axis = amount of base color left in the leaves, Shapes on Graph: distance from stream (see side label)
- Conclusion:
Before this experiment began, I had high hopes for it. Those hopes slowly fell throughout the course of it’s time, as the results became less and less conclusive and collecting data became more difficult. On the subject on conclusiveness, it is apparent from the graph as well as the table that the tree ten meters from held onto it’s leaves the longest. Many other undocumented trees in the area held onto their leaves as well, but not all were ten meters from the body of water. I think that the data shown by this particular experiment shows better how the trees lose their leaves over time rather than answering the question of which set of leaves would lose it’s color first. This field study proved my hypothesis wrong on the observed level, in that the tree planted on the bank of the stream (one meter) lost it’s leaves before the other ones. The location that this research took place in was very small, but I had to travel a bit to get there. On my walk to the research site, I passed many other maple trees, many of which lost their leaves before the ones near the stream did. I think this, contrasting my earlier statement, shows that water does play a role in leaf life, but that vast of an area was not what was being studied.
Many things went as planned in this experiment. The leaves were taken for the most part from the same spot, as seen in the photos, and the checking and measuring of their color was regular for the most part (shown in the graph/data table). Rain, other plans, as well as a lack of leaves in the last month led some of the data to be skewed, but the difference in the data that was irregularly measured was not significant enough, in my mind, to make a huge difference in the overall observation of the leaves. Some things that could have been improved were the timing of the photography (earlier in the day as to not run out come November), the regularity of the times the leaves were checked and the marking of the leaves in question. I didn’t keep the markers on the leaves the entire duration of the study, thinking that I would be able to remember which leaves were which. No such luck. There were many things I could have done better, but some that I did do well that I think were crucial to the quality of the experiment.
Overall, I think this went better than bad but not as well as it could have. Despite semi-irregular timing and bad photography, I feel that the data presented gives a good idea as to how the leaves change over time in relation to the stream they were planted near.
