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YiRoom.com
Welcome to YiRoom.com: The Place for Physics and Science Facts
Physics and Science are Fun!
Brain Twister 1
Imagine a boat floating in a pool. Now, you set a large, heavy rock into the boat's cockpit. Take your first measurement of the level of the water at edge of the pool. Next, remove the rock and drop it in the pool. Take your second measurement of the level of the water again. Presume the boat did not sink from all the weight of the rock.
During which measurement will the water's level be higher?
Science Facts
Spiders are NOT insects…they belong to the group called Arachnida. The Insecta group share common characteristics: They have bodies with three main parts, the head, thorax, and abdomen. The head has eyes, antennae and a mouth. The thorax has three pairs of legs. The whole body is protected by the exoskeleton. The Arachnida group share common characteristics: They are a smaller group of invertebrate animals with only two main body parts, the cephalothorax (head and thorax) and the abdomen. The cephalothorax has eyes, a mouth (no antennae) and four pairs of legs. This group of animals includes spiders, mites, ticks, and scorpions.
Trees – Health, Heartwood, and Sapwood
Health
The rings of a tree portray its history. When looking at a log’s rings, some rings are noticeably wider than others. If the tree grew more in one year, its ring will be wider. These wider rings represent optimal growing conditions (sun, rain, lack of pests). Small rings may represent poor growing conditions.
Heartwood
But, why is the wood in the center of the log usually darker than the outside rings? The inner wood is not transporting water any longer. These columns of cells (xylem) were dead when they conducted water, and are now severed. The empty xylem column makes a tree vulnerable to fungus growth and is dangerous to its health. In defense, the surrounding cells push material into the xylem in order to plug it up. The remaining cells produce microbe-fighting substances, oils, and lignin before dieing. This process results in the center of the tree, or the heartwood, being dead and a darker color than its outside rings.
Sapwood
The other part of the tree is the sapwood. This is the outer wood that is lighter in color. The functioning xylem tubes are conducting sap throughout the tree. Real maple syrup is made from xylem sap.
What is Bark?
Woody plants have bark, or layers of dead cork cells which are designed to protect the tree. Bark is all the layers outside of the vascular cambium. The vascular cambium is responsible for cell division and thickening of plants. Bark consists of the following four layers: cork, cork cambium, phelloderm, and secondary phloem.
This page was last updated 11/9/2008.
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