# Balance

## Related Unit Activities

This hands-on science activity teaches students who are blind and visually impaired about the balance of objects.

## Materials:

• 3 ft. x 1 ft.  wood board
• 2 in. x 4 in, x 12 in. wood board
• Empty quart or gallon metal paint cans with handles
• Wooden Spool
• Wooden flat ruler
• Gallon of sand or several rocks
• Several large objects (books, rocks, cans of food, etc.)
• Several small toys or objects (rocks, blocks, hockey pucks, cars etc.)
• Wooden spoons
• Wooden eggs

## Procedure:

### Review:

• Force is a push or a pull.
• Gravity is the force that pulls objects to the Earth.
• Even though all objects fall at the same speed, they are pulled by gravity with different amounts of force.
• The amount of force pulling on an object by gravity is called weight.
• Balance occurs when gravity pulls on all sides of an object equally.
• Gravity can make things move or fall if the forces are not balanced.

### Explain:

When you stand on the floor, gravity is pulling you down, and the floor is pushing you up.  If you are balanced, you will not move or fall.  If you are unbalanced, you can tip, or move and maybe fall.

### Demonstrate:

1. Stand with both feet together and arms out, if you do not fall or tip over, you are balanced.
2. Stand on one foot and see if you can balance, you might need to move your body a little in order to balance.

### Activity:

Explain Balance of objects:

1. Keep or put something in a position so that it does not fall.
2. When the objects move or fall, they are no longer “balanced.”
• Lift two empty cans;
• Students notice it is easy to balance because they weigh the same.
• Lift one empty can and one can filled with sand or rocks;
• Students notice, it is more difficult to balance because one can is heavier.
• On the floor, create a large lever (approximately 3 feet) with a board and wood 2x4, and have the students balance books and a few other large objects of similar weight on each end.
• Create a lever with wooden spools and rulers to balance smaller objects such as rocks, blocks, cars etc.
• Try to balance a wooden egg on a wooden spoon, standing still and walking across the room.

### Extension:

Explore moving one of the objects on the board to make objects of different weights balance.

## NGSS Standards:

3-PS2-1 Motion and Stability: Forces and Interactions

Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.