Which comes first the chicken or the Egg??
Objective:
Students will understand that gravity is the force of attraction that causes objects to fall toward the center of the earth, air resistance, or air friction, can slow down the acceleration of a falling object, and terminal speed is the speed at which the downward pull of gravity is balanced by the equal and upward opposing force of air resistance for a falling object.
Indiana Science Standards Addressed:
5.3.13 Demonstrate that Earth's gravity pulls any object toward it without touching it.
4.1.6 Explain that even a good design may fail even though steps are taken ahead of time to reduce the likelihood of failure.
Materials:
This is what will be needed for each group of four students.
• Lightweight plastic kitchen garbage-can liners
• Scissors
• Ruler
• 12 20-inch lengths of light string
• 3 plastic sandwich bags
• 3 raw eggs, probably more like a whole dozen
Estimated Time:
This activity should be split up into two days, depending on where the teacher decides to split it, it will take different amounts of time on each day. Total over the two days it should take a complete time of two and a half to three possibly four hours.
Procedure:
1. Divide your class into several small groups,
and distribute materials to each group.
2. Have students use the following directions to build three “parachutes” for an
ordinary chicken egg:
From a lightweight plastic kitchen garbage-can liner, cut out three squares.
Make one square 10”x 10”, a second square 20” x 20”, and a third square 30” by
30”.
Make a parachute out of each square by tying a piece of string to each corner of
the square, then attaching the other ends of the strings to a plastic sandwich
bag.
Place a raw egg in each of the sandwich bags.
3. Ask students to predict which egg has the best chance of surviving a drop
from about ten feet from the floor. Students should explain the reasoning behind
their predictions.
4. Have students drop each unfurled egg parachute from a height of ten feet, and
then determine whether or not their predictions were confirmed.
5. After each group has performed its experiment, ask students to describe the
changing forces that acted on the parachutes as they fell and the resulting
changes in the parachutes’ motion. How did the falls of the larger parachutes
differ from the falls of the smaller ones?
6. Review with students that gravity pulled the parachutes downward; air
resistance worked as an opposing force to gravity; the parachutes accelerated
until the air resistance equaled the gravity, at which point the parachutes
reached terminal speed; the bigger parachutes with a larger area fronting the
wind created more air resistance than the smaller ones, so the bigger parachutes
reached terminal speed earlier.
Rationale:
This lesson will teach students more aspects of speed and give them hands-on learning experience.