Joe Kittinger is still alive. It’s amazing really. This guy — born July 27, 1928 — holds the record for the highest jump ever made by a human.

It all started in 1955 when the U.S. Air Force began studying the problem pilots have when they need to jump out of a high-flying, high-speed aircraft. They have to drop quickly from the plane, and escape the thin upper atmosphere before opening a parachute. Once that’s done, they have to avoid the fatal flat spin during which they turn so fast their bodies can be torn apart. Scientists experimented with multistage parachutes for this purpose.

The human guinea pig was Kittinger, an Air Force pilot. He made 140 parachute drops. In 1960, he made his record plunge — at 31,333 metres above Earth, he jumped from a balloon. A smaller parachute opened first, to prevent him from going into a flat spin. A larger parachute opened four minutes and 36 seconds later and slowed him down further. After falling for over 31 kilometres, he landed safely.

Try this much safer experiment, using bolts in place of people!

• Heavy weight garbage bags

• Ruler

• Scissors

• Bolts

• Twist ties

• Lightweight string

• Stopwatch

Caution! Always ask an adult for help and use safety equipment.

1. Cut open the garbage bag to make a flat sheet of plastic.

2. Cut four different-sized squares: one should be 20 cm in length per side, another 30 cm per side, another 40 cm per side, and the last, 50 cm per side. You can do this by measuring along the edge from a corner, fold the plastic into a triangle, and then cut. Unfold the triangle and you have a square.

3. Tie a knot at each of the four corners of the squares. The knots will anchor the string.

4. Cut 16 pieces of string, each 40 cm long. (Four strings per parachute.)

5. Tie a string to each corner of the parachute. Tie above the knot (closest to the middle of the parachute).

6. Place your hand in the centre of the parachute so the strings dangle equally. Collect all the strings and tie them into a knot.

7. Take a twist tie, slip it through a bolt, and then attach it to the knotted string. Repeat Steps 5 through 7 for the remaining three parachutes.

8. Find a safe spot, at least two metres high (a porch, a balcony, playground equipment) and use the stopwatch to time how long it takes each parachute to land. Do three trials for each parachute and average the number of seconds.

9. Determine the relationship between size and time by using a graph like the sample graph above. The parachute surface area (square cm) goes on the left side of the graph (y-axis). The time scale (seconds) is at the bottom of the graph (x-axis). Make a dot where each of the data intersect and then connect the dots. What happened?

The force of gravity pulls the parachute and bolt to the ground. Without a parachute, the bolt would zip down. A parachute increases air resistance, also known as drag. Air pushes the parachute up, creating an opposite force to gravity, and slows it down.

Now, does the size of parachute make a difference to how quickly the bolt hits Earth? Yes. More surface area creates more drag. Your trials should show the parachute with the largest surface area (the 50-cm-square one) fell the slowest.