The Guidelines for Balsa Wood Towers
What science class would be complete without an engineering project? None because engineering is such an important part of a student's science education. A fun project the teacher and students alike will enjoy is designing and building balsa wood towers.
Balsa wood towers are an engaging and challenging engineering project for high school students. Balsa wood towers are free-standing towers constructed from various sizes of balsa wood and whichever types of glue you prefer to work with. It is recommended to use a somewhat smaller size balsa wood, but not the smallest size available. As for glue, it is best to use wood glue as a base on all of the joints and super glue over top of the wood glue for extra strength and support.
To begin, lay out the basic guidelines of the balsa wood tower construction. Instead of giving the students freedom to build any size tower, add an extra challenge to the design and construction process by setting limitations on the height, width, depth and weight of the finished tower. This forces the students to really focus on their design and be aware of the size and weight as they build as they would have to be in a professional engineering situation. This teaches them discipline to follow the rules and complete a project under strict guidelines. However, the guidelines are still loose enough in design that if you have 20 students in the class, you'll have 20 completely different balsa wood towers.
Designing a Balsa Wood Tower
Give the students a sufficient amount of time to design their towers. Once they are given the basic guidelines of the tower, they need to have time to figure out measurements and logistics of the tower he or she wants to build.
The design process requires a drawing or sketch of at least one side if all four sides are to be built identical. However, it could possibly require up to four drawings if the student prefers all four sides to be different. Often times, the strongest and most durable towers require the design of two different sides so the opposite two panels are the same.
It is in the design process where the students need to make sure the measurements will be within the limits and guidelines given.
Constructing a Balsa Wood Tower
Tower construction can take a few days depending on how specific the guidelines are and what the students are expected to do. Allow your students some freedom while also giving them a specific deadline to meet. This type of discipline will not only help in their engineering skills but in general.
Always start with building each individual side separately. Measure and cut the pieces for the sides of the tower with precision. If a mistake is made here, it can throw off the entire design. Once the sides are built accurately and have had time for the glue to dry, start putting them together piece by piece until all four pieces are aligned and glued together. Give the tower sufficient time for drying.
Once the tower is dry, you can check measurements and weight. At this point, the measurements should be accurate. If not, you either need to figure out where to cut down or redo each individual piece. When you check the weight of the tower, it's best to keep it as close to the weight limit as possible. If the tower weight is over the limit, find areas where you can either shave off extra glue or cut out a support piece that may not be essential. If you are way under weight, add a few supports and ensure that you have enough glue on all of the joints to strengthen your tower to its maximum capability.
The Competition & Grading
Once the students are finished, add excitement to the balsa wood tower engineering project with a competition for the tower that holds the most weight. By having a goal in mind as they build, the students feel like they have something to work towards.
Start by measuring and weighing each tower to make sure they qualify. If a tower doesn't meet the specifications, it can be disqualified from the competition. This is also a great time to grade the students on their projects by looking at their creativity but also making sure they followed instructions and worked within the given guidelines.
To test the towers, use a square block slightly bigger than the opening in the top of the towers with a metal hook connected to it. This metal hook then connects to another metal hook on the handle of a five-gallon bucket. The tower balances on the edges of two tables so the bucket hangs freely from the tower between the tables.
Slowly add sand evenly to the bucket until the tower snaps or breaks in some way. Disconnect the bucket from the tower and use a basic scale to weigh the bucket of sand. The tower that holds the most weight wins and the student may receive extra credit.