Lesson Plans: Science > Physical Science > Force and Friction > Friction Fires
Friction Fires
By Thomas J. Elpel
Grade Levels: This lesson plan was designed for students in grades 8 through 12. The lesson may also be used with lower grades, however, younger students may struggle to successfully start a fire.
Objectives:
1) Provide students with an experiential understanding of force and friction.
2) Allow students to experiment with lubricants and abrasives to affect friction.
3) Challenge students and foster a sense of teamwork and accomplishment as they cooperate to start a fire by "rubbing sticks together."
4) Foster integrated, whole-person learning to connect the body and mind. Students develop skills and coordination to physically assimilate and compliment academic knowledge.
Background Information: Prior to book learning, our ancestors discovered the physical world experientially through every day life. They intuitively understood scientific concepts such as force and friction through ordinary activities such as starting fire by friction. While academic understanding of force and friction is helpful to conceptually understand how the world works, it is equally important to integrate that knowledge at the physical level, so that students can intuitively apply the concepts to the real world.
Starting a fire by friction is an excellent way to integrate academic lessons, because successful fire making requires a finely tuned balance between force and friction that can only be acquired by experientially adjusting the variables.
There are dozens of different methods of starting fires by friction, but the most common and appropriate method for this lesson plan is the bow & drill or bowdrill kit. The bowdrill consists of four primary components including 1) a fireboard with a hole in it, 2) a wooden drill to spin in the hole to grind wood punk from both surfaces, 3) a bow with a string wrapped around the drill, spinning it as the bow is pulled back and forth, and 4) a hand socket to apply downward force on the drill. Pushing and pulling the bow back and forth spins the drill, grinding powdery wood punk from the drill and fireboard, which collects in a notch in the fireboard and ignites to form a hot coal or ember at 700� to 800� F. This ember is transferred to a tinder bundle, basically a bird nest-like wad of dry grass or other fibrous material, and blown into flame.
Caution: This lesson plan involves fire, as well as some use of pocketknives. Be sure to clear this exercise with school officials in advance. Knife safety should be covered prior to use of knives. Band-aids should be close at hand in case of unforeseen accidents.
Materials Needed:
Also Required or Recommended:
- A safe place for starting fires, such as a park with barbecue grills. A school lawn may be appropriate if a metal pan is placed on rocks or bricks to contain the fire without scorching the grass.
- Buckets of water, or a hose, or other fire suppression equipment.
- Marshmallows and sticks for roasting them
Presentation: Watch the Fire Volume 1 DVD and practice using the Stone Age Friction Fire Kit to attain proficiency. When confident with your skills, bring the class outdoors for an experiential lesson. Ideally, the weather should be dry to facilitate fire starting, but not too dry. Do not do this activity when there is risk of starting a wildfire.
Step One: Demonstration and Discussion: Tell the class you are going to start a fire "by rubbing sticks together," then pull out the Stone Age Friction Fire Kit and demonstrate fire making. Start out slow, asking the students to consider how force and friction come into play in the friction fire set. Then generate a hot coal, transfer the coal to a tinder bundle, and blow it into flame. Place the burning bundle into the fire pit, or step on it to smother it.
Demonstrate the technique again, discussing friction between the drill and fireboard and the forces involved, such as pushing and pulling on the bow. Discuss applying force on the hand socket to increase friction with the fireboard, as well as the use of lubricants, such as oil or wax, on top of the drill to reduce friction in the hand socket. Also consider what might happen if sand were added to the hole in the fireboard to increase friction. (It may increase drilling, but will probably hinder heating.)
Step Two: Experiential Learning: Split the class into groups of three to five students per Stone Age Friction Fire Kit. Four students per kit is ideal. Encourage cooperation and competition to see which group can get a fire first. Avoid excessive instruction to allow the students the opportunity to figure it out for themselves. Typically, two students will work the bow, one will hold down the fireboard, and the fourth student will hold the socket in place. Helpful hints may be offered if necessary to keep the class on schedule or to help one group catch up to the others. In most cases this exercise turns into a fun competition, with each group eagerly trying to be first to get a fire.
The first group to start a fire should use their tinder bundle to light kindling and start the campfire. When all teams have successfully generated a coal and lit a tinder bundle, then the entire class can celebrate by roasting marshmallows.
Step Three: Rematch: Additional experience is recommended to the extent that time and student interest permits it. Students may enjoy competitive rematches between the original groups or new groups. Students may also try starting a fire independently, although younger students may find it a challenging task for the allotted time.
Activity Two: Make Your Own: If the instructor has sufficient skills and experience, then it is possible to make friction fire kits from scratch with the class, skipping Activity One. Many soft woods (except conifers) work well for fire starting. The dry roots of cottonwood, willow, and many other trees (often found in driftwood piles along river banks) work especially well. A sturdy willow works well for a bow, with a nylon string or durable shoelace. Cottonwood bark makes an exceptional handhold.
The instructor can demonstrate making a friction fire kit in front of the class. One ideal method is to do a "knife safety demonstration," showing proper knife use for each step of the process. Students may be encouraged to guess what the instructor is making. Upon completion of the bowdrill set, the instructor can demonstrate fire making and the principles of force and friction.
The class should be split into groups of four or five students, and be provided with unprepared materials for each group to make a fire kit. Again, little instruction is necessary. Allow the students to learn through observation and experimentation. This activity requires about half an hour for the demonstration, and two or three hours for the class to manufacture their own kits and start fires. Hints can be provided to speed the process along as necessary, or to help one group catch up to another. Additional time should be allotted for roasting marshmallows and other outside entertainment.
Assessment: Conceptual understanding of force and friction can be assessed by standardized science book tests. Physical understanding of force and friction can be assessed, if necessary, through competency in starting a fire by friction. The most important evaluation, however, is whether or not the class is enjoying learning, which can be assessed by the smiles, frustrations, determination, and eventual cheers of the students in their quest for fire. The most important fire to light is not the one that roasts the marshmallows, but the fire within to discover the world.
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