Cantilever Tower Project 10.0 grams or less Minimum arm height: 10.0 cm Minimum arm length 10.0 cm

Cantilevered Towers are cranes

The base rests on the table There must be a base The base rests on the table

One arm is the CANTILEVERED ARM This arm holds the 200 gram mass There are two arms One arm is the CANTILEVERED ARM This arm holds the 200 gram mass

The other arm holds the 500 gram counterweight There are two arms The 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

Do you know why you pull a rope across a street? 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 Rectangles and squares easily deform under pressure. This does NOT make a strong and well-constructed tower. Force Tower

The tower will lean to the right or the left The tower will lean to the right or the left. Once leaning starts, breaking soon occurs Force Tower

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 The more triangles, the stronger the shape. This is true for both vertical and horizontal parts of the tower.

Time to Build Plan on several hours to draw plans, revise then build a tower. No matter how much time you plan on, you will need more than you think.

Building Supplies Cardboard Wax Paper Sewing Pins Tape Fingernail Clippers or Diagonal Cutters

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

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 Put glue on a toothpick and add it to 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.

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)

Towers may be tested early to help ensure a good grade. The Tower Project is worth 150 points, but more points than this may be earned Towers 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