from Come Fly With Me – Exploring Science through aviation and aerospace concepts.
GROUP SIZE: Individual and Large
TIME: 2-45 minute periods
TYPE OF ACTIVITY: Student Investigation
TEACHING STRATEGY: Guided Discovery
CONCEPTS: Deceleration Braking
SKILLS: Modeling Recording Data Interpreting Data
Objective: To demonstrate that the parachute system used is dependent upon the weight of the vehicle.
Materials: Set of gram weights up to one gram (washers may be substituted); three pieces of cloth one foot square; ball of string; scissors; ruler.
Teacher Background Information:
Spacecraft orbiting the earth are returned by means of braking rockets or retro-rockets which are fired in a forward direction and thus slow the craft down counteracting the inertial movement away from the Earth. The Apollo spacecraft did not use retro-rockets, however. Parachutes were used at the proper time to slow the descent. Scientists are also experimenting with paragliders and parachutes to return parts of spacecraft to earth and to land on other planets.
Have the students make octagons out of the three pieces of cloth. This can be done by cutting four triangles off the corners, 3″ x 3″. For easier identification, have the students mark the pieces of cloth in the middle with a red marker, indicating the weight attached as follows: “1/4,” “1/2,” and “1.” Have them tie a 12″ piece of string to each of the eight corners of the octagons. Tape the ends of the eight strings together on the one marked “1/4” and attach a one-quarter gram weight to the parachute and fold it neatly. Repeat with the one-half and the one gram parachutes and weights.
Go outside and drop the one-quarter weight parachute from a measured height. Have students record the time it takes for the parachute to descend. Repeat twice for an average and then do the same with the one-half gram and the one gram weighted parachute. Once your students have the data, go back to the classroom and discuss:
- What did the students observe about the velocity with which the weights returned to earth?
- As the weight of the vehicle increases, how must the parachute system change?
- Can the size of the chute be increased forever? Explain.
- Did the parachutes return to the same place each time? What force acts on a parachute that makes its destination difficult to predict?
Adapted from educational materials available from NASA Kennedy Space Center Teacher Resource Room