Why logs float
Since most of the woods are porous , their density is relatively low. As it is all comes down to density, we can say that the woods we commonly see floating on the water have a lower density than water. What will happen if we throw in the water? It floats. It sinks since the density is higher than water. Some people may wonder: Why some people are better at floating on the water even we have nearly the same density. The human body is nearly as dense as water, people good at swimming have skills in controlling their breath and muscles to get relaxed on the water.
As we have discussed in part 1 , the weight of the wood will determine if it is floatable. The animation at the top of this page, built with five images acquired by the Operational Land Imager OLI on Landsat 8 , shows the log mat zipping around the lake from spring to autumn in Gawel explained that the movement is driven by changes in the wind.
On seasonal timescales, logs are most often found at the north end of the lake during the spring and summer due to prevailing winds. By autumn the last image in the animation winds usually push the logs to the south side. The logs can also move significantly over the span of a day.
When winds die down, often during the nighttime, the logs spread out. Then as winds pick up during the day, the logs are pushed into a tight cluster. The wood itself adds organic carbon to the lake sediments.
The magnitude of the phenomenon is still being investigated. Other lakes within the blast zone—St. Helens Lake, Castle Lake, and Grizzly lake—also contain some floating logs. And elsewhere, landslides and avalanches have had a similar effect, which is why logs are often found in the lakes of steep-sided alpine areas. Geological Survey. An object that is more dense than water will sink. Testing out a few samples of wood illustrates this.
A piece of cedar, which is rather light, will easily float on top of water. It still will float, but some of the wood is submerged into the water. A third type of wood, called ipe, is from a tree that grows in Central and South America. Unlike the other two examples, this dense wood sinks all the way to the bottom when placed in water.
The density is determined by the size and number of openings in the wood.
0コメント