How to find the center of anything without a ruler

The center of an object can be found with a string.

Needed parts

• string
• any straight edge object

Straight Object

1. Take a string
2. stretch the string the full length
3. fold the string in half
4. stretch the folded string
5. it will stretch to the center

Square or Rectangle

1. Use a straight object
2. put the straight object across the two opposite corners
3. draw a faint line
4. Do the same of the opposite corners
5. the intersection of the lines is the center

Any flat object

1. hold any point on the edge of the object
2. let the object dangle with gravity
3. dangle a string with a weight from the point where it is held
4. draw a faint line along the strings path
5. hold another edge in about 1/4 of a rotation
6. Do the same with the string and mark.
7. The point of the lines intersection is the center of the object.

Any flat long object

1. This will find the center of mass for lightweight skinny objects, like a broomstick.
2. Balance the object horizontally on the top of both index fingers, with your hands held apart about, palms facing inwards.
3. Slowly bring your hands together, allow the object to gently slide across your fingers.
4. Your hands will come together under the object's center of mass.

From HowTo Wiki, a Wikia wiki.