Review of Literature:

My science fair project is on which type of wood can support the most weight, pressure treated wood or normal wood. Pressure treated wood is wood that is treated with chemicals and then left to dry for several months. Pressure treated wood is made to repel insects, withstand weather, and last a lot longer than wood. My experiment is to find out if the chemicals that are used to treat the wood also affects the wood's strength. Wood is a hard material made from the stems and roots of trees. The Earth contains about one trillion tonnes of wood. Wood is a carbon-neutral material that is also renewable (Wood). We have been using wood for a multitude of uses for a very long time. Wood is a very popular choice for building houses and furniture because of its malleability and because its shock proof and is a natural insulator. Wood is also used for its variety of color, feel, strength, and look. Wood is classified into two different types of wood: Soft Wood and Hard Wood. Soft woods include pine, hickory, ash, beech, birch, cedar, redwood, hemlock, fur, and spruce (Types of Wood). Hard woods include: oak, maple, mahogany, cherry, walnut, rosewood, and teak. Soft wood like its name is soft and is usually used for carving and art along with being used as furniture (Know Your Wood).

The kind of “normal” wood i'm using is going to be Spruce Pine. Spruce pine is a type of wood that grows in southeastern United States on the coastal plain. Spruce pine's scientific name is Pinus glabra. Spruce Pine has a distinct smell that is shared among the Pinus genus. Spruce Pine is usually sold for a moderate price and is usually used for a construction material for bridges, poles, and railroad ties. Spruce pine is one of the least common wood found in southeastern United States (Meier, Eric) Pressure treated wood is created by treating wood with chemicals. The then chemically treated wood is insect, weather, microorganism, and time resistant. It can take up to several months to dry. Pressure treated wood can last for 20 years or more.

One of the most common chemicals used in pressure treating wood is copper. With the amount of copper inside of the wood steel fasteners will corrode up to five times faster (Pressure Treated Wood) The wood is called pressure treated instead of chemically treated because the chemicals are forced into the wood by pressuring the preservatives and the wood together inside a closed cylinder. There are three main types of preservatives used in pressure treating wood : Waterborne, Creosote, and Oil–borne (penta). The amount of preservatives left in the wood after the treatment is done is measured in the wood's retention level. There are a number of retention levels available. Generally, the harsher the condition the wood is exposed to, the higher the retention level must be. Trees/ logs from normal or commercial wood is cut and has a number of different types of layers. The two primary layers are called heartwood and sapwood. Heartwood provides most of the structural strength to the living tree while the sapwood moves the sap around from the base or bottom of the tree to the top where the leaves need it. Wood preservatives penetrate sapwood easier than heartwood as a result, wood species such as Southern Pine, which have a high percentage of sapwood, are predominately used in pressure treating (Simpson Strongtie).

Work Cited

"Know Your Wood.", n.d. Web. 07 Oct. 2013.
  • This is a good website because it offers a lot of examples and pictures to go along with the information the website provides.

Meier, Eric. "Spruce Pine." The Wood Database. The Wood Database, 2013. Web. 07 Oct. 2013. <>.
  • This is a good source because it is a trusted website by many people

"Pressure Treated Wood." Home Depot. Home Depot, n.d. Web. 7 Oct. 2013. <>.

  • This is a good source because it is an actual company that sells actual pressure treated wood and is trusted by many people.

Simpson Strongtie. "Pressure Treated Wood FAQ." Simpson Strong Tie, n.d. Web. 17 Oct. 2013.
  • This is a good source because it is an actual company that is trying to inform its buyers into what they are selling.

"Types of Wood." Types of Wood. Hoove Designs, n.d. Web. 07 Oct. 2013. <>.
  • This is a good website because it offers a lot of info and examples.

"Wood." Wikipedia. Wikimedia Foundation, 11 Sept. 2013. Web. 24 Sept. 2013. <>.

  • This is a good source because it was written by experts on wood and plants. The reference list shows that they got good information from trusted sources.