Design and construct an art mobile around a general theme using physics to calculate the mobile's translational and rotational equilibrium.

ART BACKGROUND:

Alexander "Sandy" Calder (1898-1976) was an artistic pioneer who created the art form called the mobile. By the early 1970s, Calder's mobiles were famous worldwide. His sculptures ranged in size from the monumental

to jewelry-sized.

"I used to begin with fairly complete drawings, but now I start by cutting out a lot of shapes.... Some I keep because they're pleasing or dynamic. Some are bits I just happen to find. Then I arrange them, like papier collé, on a table, and "paint" them -- that is, arrange them, with wires between the pieces if it's to be a mobile, for the overall pattern. Finally I cut some more of them with my shears, calculating for balance this time."

- Alexander Calder on building a mobile, from Calder's Universe, 1976.

OBJECTIVE

To construct a hanging mobile having a minimum of three freely

swinging horizontal arms using an artistic general theme.

DIRECTIONS

1. Sketch the general plan of your mobile. Keep this sketch and all

of your work in your Projects notebook.

4. Find the mass of each element in the mobile including the rods.

5. Determine the position of each support string. Strings may not

be attached at the center of mass of a support.

6. Complete the mobile “blueprint” indicating the actual lengths,

positions of all strings, pivots and elements with the forces

clearly labeled.

7. Demonstrate by neat calculations that translational and

rotational equilibrium exists.

8. Construct your actual mobile.

HINTS

1. You are likely to achieve the best results by starting

with the lowest level and working upward.

2. Use objects of moderate mass. Do not use fragile

or expensive objects. Handmade objects are

acceptable.

3. Make the mobile simple, but visually strong. Your

mobile must be no larger than 50 cm wide, 50 cm

deep and 100 cm tall

4. Be creative!

5. Plan ahead! Calculate carefully and accurately.

PROJECT ASSESSMENT

I. Mobile 40%

- Neat construction and assembly.

- Well balanced.

- Three or more levels or extra tiers.

II. Calculations 50%

Calculations:

- Comprehensive, neat, accurate and easy-to-follow.

- Show all your work including both conditions for equilibrium

and the solved equations.

- Calculations of Percent Differences should be included