# Force and Motion: Gravity and Wind Resistance

#### Summary

Students will investigate the effects of force on objects in motion particularly as it relates to Gravity and Wind Resistance. Students will learn and use vocabulary related to the concepts of force and motion to include: force, motion, resistance, wind, acceleration. Students will perform a classroom egg-drop activity and utilize the science methods of making predictions, observing, testing, and responding to the outcome while applying concepts learned. Egg drop activity can be used any grade level with varying degrees of understanding ranging from vocab comprehension to mathematical conceptual understanding of the effects of both Gravity and Wind Resistance.

## Learning Goals

1. Define or demonstrate the Force due to Gravity.

2. Understand that air resistance, or air friction, can slow down the acceleration of a falling object.

3. Students will perform an egg-drop activity and record observations using learned concepts and vocabulary.

4. Understand the concept of terminal speed as 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.

## Context for Use

**Subject**: Physics:Classical Mechanics

**Resource Type**: Activities:Classroom Activity

**Grade Level**: Intermediate (3-5), Middle (6-8)

## Description and Teaching Materials

- Lightweight plastic kitchen garbage-can liners

- Scissors

- Ruler

- 12 20-inch lengths of light string

- 3 plastic sandwich bags

- 3 raw eggs

Procedures

1. Have students use the following directions to build three "parachutes" for an ordinary chicken egg:

2. 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".

3. 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.

4. Place a raw egg in each of the sandwich bags.

5. 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.

6. Have students drop each unfurled egg parachute from a height of ten feet, and then determine whether or not their predictions were confirmed.

7. 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?

8. 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 created more air resistance than the smaller ones, so the bigger parachutes reached terminal speed earlier.

## Teaching Notes and Tips

## Assessment

- Three points: predictions based on sound reasoning, experiment carefully performed, results accurately and completely recorded, explanations clear and logical

- Two points: predictions based on sound reasoning, experiment performed with sufficient care, results incompletely recorded, explanations acceptable

- One point: predictions based on guesswork, experiment performed with sufficient care, results incompletely or inaccurately recorded, explanations are limited

## Standards

5.2.2.1.3 Grade 5 Physical Science:Motion:An objects motion is affected by forces and can be described by the object's speed and direction it is moving:Demonstrate that a greater force on an object can produce a greater change in motion.

6.2.2.2.2 Grade 6 Physical Science: Motion: Forces have magnitude and direction and govern the motion of objects. Identify the forces acting For Example, the size of the parachute and the effects it has on the falling egg.