Did you ever dreamed of playing a seesaw on your desktop with your forgotten old friends? Did you ever needed a model for demonstrating the principles of moments? We propose here with a novel method to make an ornamental seesaw that makes your desktop at home or in the office vivid and alive. Additionally, it may serve as a teaching model showing the principle of moments. All materials used in this tutorial shall be easily accessible in an urban area especially in a medical environment.

The whole procedure usually takes no more than 15 minutes.

Step 1: Materials Required

The Desktop Seesaw is consisted of the following:

1) Seesaw plank
2) Axle
3) Seesaw base
4) Platform (Optional)

Requirements:

1) Seesaw plank - Wooden disposable medical tongue depressors (150mm x 18mm) or any uniform sized plank equivalent
2) Axle - Wooden chopsticks or any uniform sized rod equivalent
3) Seesaw base - Cardboard disposable mouthpiece or equivalent
4) Platform (Optional)
- Cardboard box cover or equivalent
- Binders / Clamps

5) Tools and Gadgets:
- Ruler or equivalent
- Scissors
- Cutter Blade
- Pencil & Rubber
- Drill or equivalent

Step 2: Making the Seesaw Plank

1) Measure the width / diameter of the axle
2) Draw the marks on the plank indicating the center of the plank and the width / diameter of the axle
3) Make the axle retainer by several sealer tapes:

one short sealer tape with its sticky side facing the sticky side of the middle region of another longer sealer tape
attach the longer sealer tape to the plank (centered)
two same sized sealer tape wrap around the longer sealer tape (as close to the rim of the axle as possible)

Note: The axle may be placed at the center of the plank to assist positioning

Step 3: Making the Seesaw Axle

1) We suggest the length of the axle = width / diameter of the base + a bit each side
(a bit = from 0.5cm to 1.0cm)
2) Trim the axle to the appropriate length

Step 4: Making the Seesaw Base

1) Draw the marks for trimming and processing:

In this project:

The center of the axle slot (hole) is around 2.8cm away from the bottom of the base
The height of the base is around 3.6cm away from the bottom of the base
The height of the plank slot is around 2cm away from the bottom of the base

2) Drill the holes for the axle
3) Cut the slot for the plank
4) Trim the height of the base

Step 5: Assembling the Parts

1) Test and try fitting the parts. If the parts are not fit, then modifications are needed
2) Place the plank into the plank slot of the seesaw base
3) Put the axle through the axle slot (holes) of the seesaw base

Caution: When penetrating the axle through the axle slot of the base and the axle retainer of the plank, keep an eye on the penetration as the axle retainer may be damaged by the axle

Step 6: Making the Platform (Optional)

In this project, a cardboard box cover is used as the platform for the seesaw.

1) Find a location for the seesaw and draw the inner circle of the base in the area of desire
2) Find the center of the circle by the bisection method:

Find the mid-point between two randomly selected points in the circumference of the circle
Draw a straight line that is perpendicular to the line joining these two selected points and through the mid-point found previously
The straight line (if drawn long enough) should penetrate the center of the circle
By repeating step 1 and 2 but selecting another two points in the same circle, you may obtain two straight lines
The intersection point of these two straight lines is the center of the corresponding circle

3) Measure the width and length of the binders / clamps
4) Draw the marks for the binders / clamps
5) Make the slots for the binders / clamps using the marks
6) Install the binders / clamps in the platform
7) Install the seesaw on the platform by the action of the binders / clamps

Step 7: Results

After applying pressure and loads on the desktop seesaw (2 sides), the seesaw system works well (e.g. rotate smoothly) and did not fail (e.g. fall down, crack or collapse), even hit by a certain amount of mechanical forces (unpublished data).

The system has also passed the loading test using weights ranged from 500g to 750g per side (i.e. up to 1.5kg total weight).
Interestingly, the sealer-tape-made axle retainer has a better endurance than we previously thought (i.e. no cracks or obvious signs of damage resulted from rapid and loaded rotation).

Step 8: Summary

This tutorial provides you a new way to create a seesaw which serves as an ornament, a teaching model or a toy for you. The desktop seesaw is inexpensive, disposable, flexible and light weight. Additionally, it is easy to make and process. The plug-and-play design makes the system flexible and easy to modify its parts according to the demand of the user.

Acknowledgements

The Hong Kong Polytechnic University

References

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