Though you can't make a parachute that would be safe for skydiving, you can make a miniature parachute as an experiment or to demonstrate how a parachute works and other aerodynamic principles.
Tie a knot in each corner of the bandanna. Make each knot as small as possible and as far in the corner as possible.
Cut the string into four 16-inch lengths. Tie each piece of string to a corner of the bandanna.
Test all of the knots to make sure you firmly tied them. The parachute will only work if the knots in both the bandanna and the strings are secure.
Find the center of the bandanna. Hold it in one hand as you pull all four strings with the other hand. Tie the four strings together.
Attach a washer to the four strings. You need weight at the end of the strings for your parachute to work properly.
Test the parachute by dropping it from a height of 6 feet. If it doesn't fill fully with air or it just crashes, your strings are probably uneven. Untie the washer and tie it again, ensuring that all the strings are of equal length from the washer to the bandanna.
Add an additional object onto the washer once the parachute works to see how more weight affects the parachute's performance.