Tinsel Strength of Wood By: Connor Clements

Abstract The tinsel strength of wood is how much pressure or weight you can put on the center part of a horizontal piece of wood, ½ an inch thick, ½ an inch wide, and 20 inches long until it breaks. To test this I set up some stands in my basement that were 18 inches apart and high off the ground. I then strung weights on steel wire to see how much weight certain types of wood could hold. Maple was the strongest at 79 pounds. Cherry was second with 71. Third was Oak at 69 pounds. Pine was forth with 67 pounds. Eastern cedar was fifth with 44.5 pounds and plywood was sixth with 29 pounds. The weight is figured by the maximum that a piece of that type of wood achieved.

Review of Literature According to Marcelene Edward’s article, (2006), the strength of plywood depends on many different factors. The first is how thick and long the piece of plywood is. Thicker means it is stronger and longer means it is weaker. The number of layers also has an important role. If there are more layers, the piece is stronger. If the piece is in a wet environment, then the glue needs to be waterproof otherwise the layers will just fall apart. To test the tinsel strength of wood I needed to know if a piece was going to be strong or weak. According to Mike Jackson in his article, (2007), the grain of the wood needs to be parallel to the cut in the wood. This makes the piece of wood break all of it’s fibers when it breaks instead of just splitting between the layers. Another factor is knots. Knots disrupt the grain pattern and leave holes in wood. If there is a whole in the piece of wood and the grain pattern is altered, it is obviously going to be very weak. The stiffness of a piece of wood will affect the tinsel strength. Tim Lovett’s article, (2004), gave me Hankinson’s Formula. Hankinson’s formula is used to calculate the stiffness of wood. It takes the angel of the grain compared to the cut to calculate the stiffness of a piece. Obviously a higher stiffness will be stronger. Graham M. Francis’ article, (2008), tells me which types of woods will be stronger than others. Hard woods like oak and maple will be stronger than soft woods like pine. My data backed this up. Maple was the strongest at a maximum of 79 pounds. Cherry was second at a maximum of 71 pounds. Oak was third with 69 pounds. Pine was fourth with a maximum of 67 pounds. Eastern cedar was fifth with a maximum of Last was plywood with a maximum of 29. Oak, maple, and cherry are hardwoods. Pine and eastern cedar are soft woods. Works Cited Edwards, Marcelene. "Crack Crew Tests Wood's Strength." News Tribune Print. Francis, Graham M. Tensile Strength of Wood. Tensile Strength of Wood Web. 17 Nov Jackson, Mike. "Grading Timber." H2O Print. Lovett, Tim. "Wood Strength." Wood Strength. July Web. 17 Nov

Question, Problem Statement, Hypothesis Project Idea: Which types of woods have a higher tensile strength? Hypothesis: If a certain type of wood, Oak, is denser, then that type of wood will have a higher tensile strength than types of wood that are less dense, Eastern Cedar.

Experimental Design Project Idea: Which types of woods have a higher tensile strength? Hypothesis: If a certain type of wood, Oak, is denser, then that type of wood will have a higher tensile strength than types of wood that are less dense, Eastern Cedar. Materials list: 3 pieces that are 1.3centimeters thick, 1.3 centimeters wide, and 51 centimeters long of Oak, Maple, Eastern Cedar, Pine, Cherry, Popular, Plywood A stand that is tall enough to string weights to a piece of wood and is 48 centimeters wide Steel wire Weights starting at 1 gram and going up in 1 gram increments A chart and a pencil to graph the results. Independent Variables: Oak Maple Eastern Cedar Pine Cherry Popular Plywood Dependent variables: The tinsel strength of the pieces of wood in grams. Constants: A stand to test the pieces on Steel wire Weights going up by 1 gram each The experiment will take place in one day Moisture content of the wood Size of the pieces Air temperature – inside house Temperature of the wood Control: Plywood

Procedure: The first thing that you would want to do is build a stand that is 48 centimeters wide and 92 centimeters tall to test your pieces of wood. Next you will want to cut all your wood the exact same size of 1.3 centimeters thick, 1.3 centimeters wide, and 51 centimeters long. Next you will want to calculate the density of your wood by taking you mass in grams and dividing it by cubic centimeters. Now you will want to take your steel wire and wrap it around the exact center of the piece of wood. After that you will want to mark 2.5 centimeters in on each side of your piece of wood. Take that mark and put it on the stand at that mark. Next you will need to make a graph to record your data on. Now you will take your pieces and test them using 1 gram weights that go up by 1 gram. Once the piece of wood breaks completely in half you will want to subtract one gram from the weight and that will be the tinsel strength of that piece of wood. You want to take that weight and record it on your graph. Do this until you have the tinsel strength for all of your pieces of wood.

Step by step procedure from experimental design The first thing that you would want to do is build a stand that is 48 centimeters wide and 92 centimeters tall to test your pieces of wood. Next you will want to cut all your wood the exact same size of 1.3 centimeters thick, 1.3 centimeters wide, and 51 centimeters long. Next you will want to calculate the density of your wood by taking you mass in grams and dividing it by cubic centimeters. Now you will want to take your steel wire and wrap it around the exact center of the piece of wood. After that you will want to mark 2.5 centimeters in on each side of your piece of wood. Take that mark and put it on the stand at that mark. Next you will need to make a graph to record your data on. Now you will take your pieces and test them using 1 gram weights that go up by 1 gram. Once the piece of wood breaks completely in half you will want to subtract one gram from the weight and that will be the tinsel strength of that piece of wood. You want to take that weight and record it on your graph. Do this until you have the tinsel strength for all of your pieces of wood.

Results table, graph In my experiment, Maple was the winner with an average of 78 and 2/3 pounds until it snapped. This is partly because the pieces of maple did not have any knots, the grain was parallel to the wood, and there were no cracks or any type of other defects in the wood. The main reason maple won is because of the shape in the pours of the wood. The shape was the best for holding loads in that particular direction.

Conclusions and Future Studies My Hypothesis was disproven because I thought that oak would be the strongest when the actual winner was maple. Oak came in third behind cherry. The only change I would have made to my experiment is to make the pieces smaller. They took a lot of weight to break and when the weights fell it ruined the carpet in my basement.

Acknowledgments I want to thank Mr. Hazelbeck, my shop teacher, for allowing me to get and cut the wood. He also helped me with my research. I would also like to thank Mrs. Richards for helping me through the whole project.

Bibliography Edwards, Marcelene. "Crack Crew Tests Wood's Strength." News Tribune Print. Francis, Graham M. Tensile Strength of Wood. Tensile Strength of Wood Web. 17 Nov Jackson, Mike. "Grading Timber." H2O Print. Lovett, Tim. "Wood Strength." Wood Strength. July Web. 17 Nov