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

2. Cantilevered Towers are cranes

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

4. 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

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

6. There seems to be two basic styles of cantilevered towers
The Tall Crane and the Vee Crane

7. Glue, sewing thread and any type of wooden toothpick may be used
Remember, thread is your friend!

8. 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

9. 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

10. 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

11. 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

12. Epoxies Avoid using epoxies Heavy after drying
Must mix in the proper ratio
Does not dry fast
Does not soak into wood

13. ARM HEIGHT - is measured with a ruler on a right triangle.

14. ARM HEIGHT - is measured to the lowest part of the arm above the center of the 200 gram mass

15. ARM LENGTH - is measured from the front of the base to the point under the center of the 200 gram mass

22. 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?

23. Thread works well under tension forces
Tension forces pull things apart

24. Tension Forces

25. Thread does NOT work well under compressional forces
Compressional forces PUSH things apart

26. 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!

27. 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

28. 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

29. Triangles make for strong towers
The more triangles,
the stronger the tower

30. Triangles strengthen towers by keeping the tower rigid.
The diagonal prevents the deformation of the shape

31. 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.

36. 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.

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

38. 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.

39. Add photo of cardboard with pins sticking out of it

40. 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

41. Insert photo of drawing plans with a ruler

42. Include photo showing toothpick and spans smaller than a toothpick

43. 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.

44. Tape the plans onto the cardboard

45. Place wax paper over the plans

46. 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.

47. Place toothpicks on the plans

48. Use nail clippers or diagonal wire cutters to cut toothpicks to the correct length

49. Put glue on toothpicks to be added to the tower

50. Use pins to hold the toothpicks in place

51. Use a box to protect and carry the tower

52. If the tower breaks before it is tested, it MUST be repaired or rebuilt for a grade to be earned.

53. 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)

54. 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!

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