After this lesson, students should be able to:

• Understand and define a force.
• Identify several different types of forces used by both artists and engineers.
• Describe how physical forces are used in the creation of art.
• Identify careers that use concepts of forces and art to design and create things for society.
• Use elements of art, principles of design and styles of art to communicate their understanding of forces.
• Apply elements of art and principles of design to create works of art.
• Experiment with materials, tools, techniques and processes that enhance communication of ideas through art.

Figure 2. Elephant and Mouse by Daniel Ostermiller, Museum of Outdoor Art, Greenwood Plaza, CO. click for copyright

A force is a push or a pull on an object. Gravity is one of the most common forces we encounter every day. It is always pushing us towards the center of the Earth. In outer space, we are very far away from the center of the Earth and therefore the gravitational forces are much smaller. This is why astronauts appear to be floating.

Some sculptures look as if they would topple over at any minute. Are they actually defying gravity? Well, no. The sculpture is balanced on its center of mass (see Figure 2). The center of mass of an object is the point at which all of an object's mass may be considered to be concentrated. This means that the object can balance on a point as long as that point is directly below the object's center of mass. The artists of these sculptures carefully design their work so that the center of mass of the object is supported. We carefully align our own center of mass when walking on tightrope or a balance beam by pulling our hands out to our sides.

Figure 3. Slice of Wind by Ned Kahn, Boulder, CO. This wind-driven, kinetic sculpture measures 10 x 10 feet and features 10,000 Mylar disks that move freely on rivets, allowing the wind to generate an infinite number of patterns on the sculpture's face. Visitors can use the handle to create their own modal vibration patterns. click for copyright

The wind also creates forces. On blustery days you can see the wind move the leaves on a tree. Wind forces also push sailboats through water. Similar forces cause movement in outdoor sculptures (see Figure 3), such as wind chimes or mobiles. Wind currents are created by hot air rising and cool air settling. Hot air rises because it is less dense than cool air. This same principal works both outside and inside buildings, although the outside currents tend to be a lot stronger. These convection currents are what cause wind chimes to sing and mobiles to rotate.

Not all forces occur naturally. For example, people can create forces using energy from the food they eat. This happens when we push someone on a swing, move a chair across a room or play tug of war. When we read pop-up books we apply very small forces to tabs and flaps to make them move. When we rotate a flap, it is called a centrifugal force. A centrifugal force is also created when an ice-skater turns or we spin in a chair.

Have the students identify other art forms that are concerned with forces and research the impact of these forces on the discipline, such as ballet (spins and lifts) or theater (rotating stages, levitating actors/actresses and lowering curtains).