The Effect of Wood Species on Heat Output and Burning Time

student picture

Researched by Ethan W.
2004-05





PURPOSE

The first purpose of this experiment was to determine the effect of different species of wood on heat output when burned.

The second purpose of this experiment was to determine the effect of different species of wood on burning time.

I became interested in this idea when I was camping. I noticed that when we put different types of wood in the fire the heat and time before we had to put more wood on varied.

The information gained from this experiment could be useful to anyone who heats their house with wood or anyone who spends time in the outdoors depending on a fire.





HYPOTHESIS

My first hypothesis was that oak would produce the most heat.

My second hypothesis was that maple would produce the least amount of heat.

My third hypothesis was that oak would burn the longest.

My fourth hypothesis was that maple would burn the shortest.

I based my first and second hypotheses on Mother’s Wood-Burning Almanac that said “The denser the wood the more heat output”, and Hardwood Density that said oak was the most dense.

I based my third and forth hypotheses on World Book Encyclopedia that said “The denser the wood the longer it will burn”, and Hardwood Density that said oak is the most dense.
 




EXPERIMENT DESIGN

The constants in this study were:
     • The mass of the wood burned
     • The thermometer used
     • The amount of water used
     • The number of tests done
     • The water container used
     • The place the experiment was conducted
     • The stop watch used

The manipulated variable was the species of wood burned.

The responding variables were how much heat the species of wood put out and how long the wood burned.

To measure the responding variable I used a digital timer and a temperature probe in a container filled with cold water.





MATERIALS

QUANTITY
ITEM DESCRIPTION
445.5 grams   oak
445.5 grams birch
445.5 grams maple
1 lighter
1 stopwatch
96 liters tap water
1 fireplace with barbecue rack
1 laptop
1 Logger Pro system with temperature probe
1 power strip
1 extension cord
1 pitcher to measure water
1
triple beam balance
1
saw




PROCEDURES

1. Cut wood to a consistent size for testing
         a. Cut the 445.5 grams of wood into pieces. Start at 1cm x 1cm and then slowly get larger.
         b. Sort the wood after it is cut so there will be a consistent mass of wood for each test.
2. Prepare the test apparatus
         a. Set the water container on the barbecue rack inside the fireplace.
         b. Connect the Logger Pro to the computer and turn them both on.
         c. Connect the temperature probe to the Logger Pro and set it in the water container.
3. Conduct trials;
         a. Measure 16 liters of cold tap water into the container.
         b. Determine the beginning temperature of the water.
         c. Build a tepee using 222.75 grams of the wood to be tested
         d. Start the fire by lighting the newspaper in the middle.
         e. Start the stopwatch and press the collect button on the Logger Pro 3.0 software.
         f. Monitor the fire to make sure it is burning well.  It may be necessary to rearrange and consolidate the wood to keep it burning at its best.
         g. Stop timer when fire is completely dead
         h. Save the temperature data on computer for this trial
4. Repeat step 3 until 2 trials have been completed
5. Repeat steps 3-4 for each wood type
6. Average results for each wood species





  RESULTS

The original first purpose of this experiment was to determine the effect of different species of wood on heat output when burned.

The original second purpose of this experiment was to determine the effect of different types of wood on burning time.

The results of the experiment were that maple burned the hottest with a temperature gain of 13.76° Celsius and produced 220.16 Kilo calories.  The next hottest was oak that had a change in temperature of 12.2° Celsius and produced 195.16 Kilo calories.  Birch came in last with a change in temperature of 12.06° Celsius and produced 192.95 Kilo calories. 

The wood that burned for the longest time was oak with a total burning time of 29 minutes.  The next longest was birch that burned 25.8 minutes.  The wood that burned for the shortest time was maple with a time of 24.3 minutes.


See my table and graphs





 CONCLUSION

My first hypothesis was that oak would produce the most heat.

The results indicate that this hypothesis should be rejected.

My second hypothesis was that maple would produce the least amount of heat.

The results indicate that this hypothesis should be rejected

My third hypothesis was that oak would burn the longest.

The results indicate that this hypothesis should be accepted.

My fourth hypothesis was that maple would burn the shortest.

The results indicate that this hypothesis should be accepted.


Because of the results of this experiment, I wonder if the mass of the wood burned doubled or tripled, would the heat gain if the water also doubled or tripled.
If I were to conduct this project again I would have a bigger fire, conduct more trials, and have more species of wood and use. 


 
 
 




 RESEARCH REPORT

Introduction
Every year many people in America rely on fire for heat, to cook food, and for enjoyment. They need to know which species of wood is going to be the most efficient for what they need to do. Lumberyards rely on tree production for their business and many people's jobs.

Fire
Fire is an important resource.  Without it human living would be tough.  It is used to heat homes and keep people warm in the wilderness or anywhere in the outdoors.  It is also used for pleasure and to cook food.  In order for fire to exist there must be several things going on.  Fire needs fuel and oxygen to burn but in order for there to be burning there must be oxidation, reduction, and combustion.

Combustion
Combustion is a chemical reaction that gives off heat and light.  It involves the rapid combination of oxygen and fuel to produce burning.  The fuel can be a solid, liquid, or gas.  In order for something to burn it must first be vaporized.  The vaporization process involves molecules on the surface being attracted to one another.  Heat can energize these molecules to break apart and escape to the air.  Once in the air they combust because of oxidation and reduction.

Oxidation

Oxidation is a chemical reaction in which a substance loses electrons.  This usually involves a substance combining with oxygen but oxidation can occur without that.  Oxidation originally referred to a substance combining with oxygen.  That was before scientists found that it didn’t have to.  The electrons that are released must be captured by another substance.  Oxidation is always accompanied by reduction and the combined transfer is known as the redox process.

Reduction
Reduction is a chemical reaction in which a substance gains electrons.  The substance either combines with hydrogen or loses oxygen.  There are many processes that involve reduction.  Reduction is the opposite of oxidation and both processes always occur together. 

Wood
Wood is the substance most commonly used for burning.  Wood is the product of trees.  Once trees are cut down they either go to a mill to be made into lumber or are made into firewood to be sold to consumers.  It is also possible for anyone to obtain a permit to cut down trees for their own use.  There are two different types of wood, hard wood and soft wood.  Hard wood is the product of a broad-leaved tree like oak or maple.  Soft wood is an open grained wood from pine trees and other evergreens.  Paper is most commonly made from soft wood and hard wood is usually used to make carvings, furniture, and other decorations or furnishings made from wood.  Hard woods will produce more heat and burn longer than soft woods, but are harder to ignite.  Soft woods burn fast and or to ignite, so they are usually used for kindling.

Thermodynamics
Thermodynamics is a branch of physics that studies various forms of energy and its conversion from one form to another. 

The first law of thermodynamics states that energy in a system can’t be created or destroyed.  The energy in that system always remains constant.  It is either converted from one form to another or it is transferred to a different system.

The second law of thermodynamics refers to the natural direction of energy.  It says that energy always flows from a hot object to a less hot object. The difference in temperature determines the rate of speed in which the energy flows.  When the molecules and atoms in an object are moving very rapidly it will be hot.  The faster they flow the hotter it is. Benoit-Pierre Clapeyron found the second law in 1834.

The third law of thermodynamics states that an object cannot reach absolute zero.  It can come close, but can’t actually reach it.  Absolute zero is the temperature at which the atoms stop moving.  When an object gets close to absolute zero it starts to change.  Absolute zero is –273 degrees Celsius.  Hermann Nernst found the third law in 1906.

Summary
Every year many people in the United States rely on fire to keep them warm, cook their food, and give them many hours of fun and pleasure.  Tree production and the lumber businesses provide many people’s jobs.  We need to know which species of tree is going to be the most energy efficient and give the most burning time.
BIBLIOGRAPHY

"Combustion,"  The Columbia Encyclopedia,  2002.

“Hardwoods.”  December 10, 2004.
http://waynesword.palomar.edu/plscpt99.htm

Hapeman, Cathleen J.   "Oxidation,"  World Book Encyclopedia,  2004.

Hapeman, Cathleen J.   "Reduction,"  World Book Encyclopedia,  2004.

Quintiere, James G. "Fire." World Book Online Reference Center. 2005. World Book, Inc. 10 Jan. 2005. <http://www.worldbookonline.com/wb/Article?id=ar197340>.

Quintiere, James G.   "Combustion,"  World Book Encyclopedia,  2004.

“Mother’s Wood Burning Almanac”.  December 10, 2004.
http://www.motherearthsnews.com/menarch/archive/107/107-042-01.htm

“Properties of Wood”.  January 28, 2005.
http://www.selah.k12.wa.us/SOAR/sciproj2004/MaxR.html#Research


ACKNOWLEDGEMENTS

The I would like to thank the following people for helping make my project possible:
     •My parents for helping me with my experiment and every aspect of my project.
     •Mr. Newkirk for helping me every step of the way.
     •Mrs. Helms for being there when I needed extra help.


Top of page

Menu of 2004-2005 Science Projects

Back to the Selah Homepage