As log driving is a very simple and energy saving way of transporting lumber from upstream downstream, it is commonly used in cities and provinces close to waterways such as Vancouver and British Columbia. As the lumber industry is very important in supporting the Canadian economy, it is heavily all over Canada. Our goal of the experiment was to find the better type of water for transporting the lumber which will weaken the wood less. We decided to use strength to decide how strong a piece of wood will be. By testing how much dirt a piece of wood can carry before snapping after 4 different time periods, we were able to gather enough data to form a general trend of decrease.
Our experiment went very smoothly and we were able to keep our controlled variables consistent throughout the whole process. A main concern we had before starting our experiment was keeping the temperature consistent because of constant change of temperature both inside the house and outside. As is was also snowing during the time of our experiment, we had to constantly move the containers both upstairs and down stairs to keep the temperature the same. It was slightly difficult because the temperature would drastically change all of a sudden because the temperature outside the house rose or dropped but we were able to manage fairly well by keeping an eye on the containers every few hours or so. However a problem with this was that we were not able to check on the containers while we slept, or while we were at school. In trying to overcome this difficulty, we placed them in rather secluded locations, and had a parent once in a while monitor any activity.
The results were consistent because the the results of the first trial and the second one were very similar and both followed the general decreasing trend. One interesting note we made was the consistency of the water inside the containers. The water inside fresh water container became slightly slimy on day 21. The liquid wrapped around the sticks creating a sort of mask. When we pulled the sticks out of the container, the liquid felt slimy and more viscous than water. We were both very surprised with this finding because we did not expect that the water was able to increase in viscosity. This change in viscosity may be the cause of bacteria inside of the water mixed with the components of the popsicle stick. On the other hand we did not observe any change of consistency in the ocean water. It’s consistency remained the same throughout the whole entire experiment. This could be due to the fact that the seawater has more living organisms within it, and their reaction with the wood caused the water to become denser. We did not notice any form of rotting within the wood which was a surprise considering the amount of time it was left in the water and in relatively warm temperatures, suggesting that the water actually prevents mold from building.
Sources of uncertainty:
As the popsicle sticks that were used for this experiment were made from Birch wood, the results may vary if a different type of wood is used for the experiment. Birch is a hard, heavy, close grained wood. Woods such as Oak, which are in the same density category as Birch will most likely experience decaying effects if used for the experiment. However if softer woods are used such as Cedar or Douglas fir may experience different decay rate or loss in strength. Another component that can affect the deterioration of fresh lumber is that they have a thick layer of bark. Bark on the tree can serve as a protection barrier against the bacteria in the water and block out the the moisture which can keep the insides of the tree safe from loss of strength.
A flaw we found during our experiment was that the popsicle sticks that were submerged in fresh water were very bendy and hard to break. This proved to be a problem because they were able to withstand a significant more amount of weight than the sticks submerged in ocean water. By touch the ocean water popsicle sticks were drastically more rigid and seemed more solid. The sticks submerged in freshwater started to bend earlier than the sticks submerged in ocean water when the same weight was added. As weight was increased, the fresh water sticks bent, but did not break. The seawater sticks, however, with the additional weight, ended up snapping at a faster rate than the sticks from fresh water. This result proved the hypothesis false, with the sea water sticks being more fragile than the fresh water sticks.
Future Works: If we were to continue this study in a future experiment we would make a few changes. As we used popsicle sticks made solely out of Birch, next time we will use popsicle sticks made from different types of wood, including both soft and hard lumber. More ways to test durability would also be put into effect, for simply testing if a stick would snap proved to be inefficient and slightly inaccurate. Next time we will also measure the effect leaving the wood outside to dry for a day after taking them out from the containers of water. This will further make "weathering" of the wood more realistic and provide better and more reliable results.