Part of Unit: Designing and Building Projects
Lesson Plan Overview / Details
Students quite often do not comprehend what it costs to build a project. This lesson will show them how to calculate board footage and the cost of materials.
It also has an outdoor activity where students will explore their own campus to calculate the board footage of material in trees on their campus. It applys math functions that they learn in their math class and shows them real world application for the math they learn.
- Material cost estimation
- 10 Minutes
- Board Footage overview
- 15 Minutes
- Guided practice of material cost
- 20 Minutes
- Self practice of project cost
- 15 Minutes
California Career and Technical Education Standards
California Academic Content Standards (Reinforced)
Objectives and Goals
Students will be able to calculate cost of a project by understanding how to calculate board footage.
Activities in this Lesson
- What is it worth? - Hooks / Set
When students enter the room have multiple pieces of material sitting on the classroom tables. Each table will have a certain wood type ( ex. maple, oak, pine). Have all the materials be 3/4" - 1" so it will make the calculations a little easier.
Up on the board have the cost/board foot for the material. Provide a brief basic description of that a board foot is 12"x12" piece.
Ask the students at their table to guess how much each pile of material at their table is worth? Using the information on the board (cost/BF) estimate the cost.
Have each student put their name on a piece of paper and turn it in with the estimated cost of the material at their table
NOTE: Each student turns in his/her own estimate, this part is not a group effort.
- Measuring the material - Guided Practice
Board footage can be confusing for some students. They are not always receptive to doing math in woodshop so you have to trick them. By making it a competition students change their attitude toward work.
When you start to talk about the board footage and show the powerpoint, have samples that match the samples in the PPT. On slide 4 it shows 4 boards that all equal 1 BF or 144 Cubic inches. Have the samples the same size and draw on the pieces grid to show that it is equal to 144 cu inch or 1 board foot.
Students will work in pairs from their table. They are going to figure out how much the material at their table is worth by calculating the board footage of all the material at their table.
Kids love competition - The top 3 pairs of students with the closest cost will get a prize ( I use simple bite size candy bars. Kids and food are great motivators.)
- What's a Board Foot? - Lecture
Give all students a copy of the blank bill of materials spreadsheet. They will measure the size of all the pieces at their table to be able to get an accurate measurement of the overall cost and board footage.
All material is sold by the foot. Some material is sold by the square foot, some by the linear foot and most by the board foot.
Note: This lesson is about board footage, briefly talk about what square feet and linear feet are but save that info for another lesson.
We are going to learn how to calculate board footage so you will be able to estimate the cost of building a project.
When trying to figure board footage we will use a calculator
the formula for board footage is - P x L x W x T/144=BF
We will always round up on all dimensions
.5 =1" or 3/4=1" or 2 5/8 = 3" or 11 1/8 = 12"
When teaching the students about board footage skip the column about the number of pieces. You can work that section in when you do the guided practice with the sample projects.
Working in pairs each student will fill in the dimensions of all the material at their table on the blank form. Each student will keep his own form. Have them only fill in the thickness, length and width of EACH individual piece at their table.
NOTE: Be sure to number all the materials so students can be sure they got all of the pieces on their paper. You can then check for measuring accuracy also by having the pieces numbered.
In the column for material type, be sure they write what material they are measuring and then put the UNIT COST total for that material in the appropriate column on the sheet.
In the powerpoint, have student follow along on the formula so they can calculate it out. The teacher must know how much is at each table to get an accurate assessment so you can check for understanding as you work your way along.
When all the students have completed the measuring, check with the class to see what the total was for each group of material.
At this point check to see what 3 pairs had the closest total for the material at their table.
- BillOfMaterials.xls [ Download ] Spread sheet for calculating board footage
- Blank Bill of Materials.xls [ Download ] Blank form for completing a bill of materials
- bed step stool.jpg [ View Image ] [ Download Original ] Sample Project
- blue bird nesting box.jpg [ View Image ] [ Download Original ] Sample project
- board footage 3 [ Download ]
- Practice on a project - Independent Practice
Give each student a copy of the step stool plan. They are going to work with you and the power point on filling in the material.
After they have that one done, have them add the blue bird nesting box to the bottom half of the sheet. They can calculate what the total board footage is for both projects together.
- Assessment Types:
- Teacher-Made Test,
For the assessment of the lesson on board footage I will make 8 copies of various project plans. It makes a little more work for the instructor to grade, but it also cuts down on the cheating. Give a different plan to each person at the table.
The more practice the better for students to learn how to calculate board footage.