cantilever tower project 10.0 grams or less minimum arm height: 10.0 cm minimum arm length 10.0 cm
TRANSCRIPT
Cantilever Tower Project
• 10.0 grams or less
• Minimum arm height: 10.0 cm
• Minimum arm length 10.0 cm
Cantilevered Towers are cranes
There must be a base
The base rests on the table
There are two armsOne arm is the CANTILEVERED ARM
This arm holds the 200 gram mass
There are two armsThe other arm holds the 500 gram
counterweight
There seems to be two basic styles of cantilevered towers
The Tall Crane and the Vee Crane
Glue, sewing thread and any type of wooden toothpick may be used
Remember, thread is your friend!
Toothpicks come in many shapes
10.0 grams uses about 150 flat toothpicks. These are weak and vary
a lot in quality
Larger and thicker toothpicks weigh more, but are harder to break.
It is okay to mix the types of toothpicks
Glue is IMPORTANT
• Do NOT use hot glue– Hot glue is too flexible and heavy– Joints will flex – The tower and arms will bend– The tower will weigh more than 10.0 grams– You will be VERY UNHAPPY
White or Wood Glue• Easy to use
• Soaks into the wood
• Holds very well
• Easy to clean up
• Does not need ventilation during use
• Does not dry quickly
Superglues • Dries quickly - much faster on flesh
than on wood
• Does NOT soak into wood
• Accelerator - catalyst to INSTANTLY harden the superglue
• Sticks to wax paper and plans
Epoxies• Avoid using epoxies
• Heavy after drying
• Must mix in the proper ratio
• Does not dry fast
• Does not soak into wood
ARM HEIGHT - is measured with a ruler on a right triangle.
ARM HEIGHT - is measured to the lowest part of the arm above the center of the 200 gram mass
ARM LENGTH - is measured from the front of the base to the point under the
center of the 200 gram mass
Thread Story
Do you know why you pull a rope across a street?
Well - have you ever tried to push a rope across a street?
Thread works well under tension forces
Tension forces pull
things apart
Tension Forces
Thread does NOT work well under compressional forces
Compressional forces PUSH things apart
Thread is your FRIEND!
• Sewing thread is light and strong
•Thread works well under tension
•Thread does not work well under compression forces
•Thread is light and does NOT add a lot of mass!
Rectangles and squares easily deform under pressure. This does
NOT make a strong and well-constructed tower.
Tower
Force
The tower will lean to the right or the left. Once leaning starts,
breaking soon occurs
Tower
Force
Triangles make for strong towers
The more triangles, the stronger the tower
Triangles strengthen towers by keeping the tower rigid.
The diagonal prevents the deformation of the shape
The more triangles, the stronger the
shape. This is true for both vertical and
horizontal parts of the tower.
Time to Build
No matter how much time you plan on, you will need more than you think.
Plan on several hours to draw plans, revise then build a tower.
Building Supplies
• Cardboard
• Wax Paper
• Sewing Pins
• Tape
• Fingernail Clippers or
• Diagonal Cutters
Cardboard
Use corrugated cardboard to build upon.
The pins easily stick into the cardboard..
The entire set up may be easily picked up, moved and stored.
Add photo of cardboard with pins sticking out of it
Plans
Draw plans the actual size the tower will be
Use a ruler to draw straight lines
Avoid making spans larger than the toothpicks to be used in building
Insert photo of drawing plans with a ruler
Include photo showing toothpick and spans smaller than a toothpick
Place the plans on the cardboard.
Tape the plans down so the plans cannot move.
Cover the plans with wax paper to protect the plans from glue.
Tape the plans onto the cardboard
Place wax paper over the plans
Place toothpicks over the plans
Use pins to hold the toothpicks in place until the glue dries.
When the side is finished, take out all the pins and remove the side from the wax paper.
Put glue on a toothpick and add it to the plans.
Place toothpicks on the plans
Use nail clippers or diagonal wire cutters to cut toothpicks
to the correct length
Put glue on toothpicks to be added to the tower
Use pins to hold the toothpicks in place
Use a box to protect and carry the tower
If the tower breaks before it is tested, it
MUST be repaired or rebuilt for a grade to be
earned.
The diagrams, answers to the questions and the sign off sheet
should be turned in before leaving school the day the tower is due
Make the diagrams BEFORE testing the tower
(Just in case the tower breaks)
The Tower Project is worth 150 points, but more points than this
may be earnedTowers may be tested early
to help ensure a
good grade.
Don’t wait to start working!
Cantilever Tower Project
• 10.0 grams or less
• Minimum arm height: 10.0 cm
• Minimum arm length 10.0 cm