# Air Friction

Topics: Force, Drag equation, Drag Pages: 2 (355 words) Published: February 14, 2013
EFFECT OF SURFACE AREA ON AIR FRICTION
Design

Background Information:
Air resistance, also called drag, is the forces that are in opposition to the relative motion of an object through the air. Drag forces act opposite to the oncoming flow velocity. Size and shape are the two factors that affect air resistance. Air resistance depends on the surface area, so, as the surface area increases, the air resistance increases. When an object is falling, air resistance acts to push it back up. This is only true for objects falling straight down. If the object was falling left or right, then air resistance would be opposite. Air resistance is the opposite of gravity for an object falling down.

Research Question: How does the change in the surface area of a paper cake mold that is attached to a paperclip, affect the time it takes for the cake mold to reach the ground?

Hypothesis: As the surface area of the paper cake mold increases, the time it takes for the parachute to reach the ground will also increase, which would show an increase in the air friction.

Variables:
Dependent Variable: Falling time of the object.
Independent Variable: Surface area of the paper cake mold.
Controlled Variables:
* Mass of the paper cake mold
* Mass of the paperclip
* The height from the ground that the cake mold is released * Material of the cake mold

Materials:
* 5 cake molds with different sizes
* 25 pieces of 5 cm string
* 5 identical paperclips
* A hole puncher
* A 2 meter ruler
* A chronometer

Method:
1. Punch 5 holes with equal distances from each other to 5 cake molds with different sizes. 2. Tie one of the 5cm strings to each hole and tie the open endings of the strings to each other. 3. Attach the paperclips to the tied strings.

4. Relese the parachute from a 2 meter height and start the chronometer at the same time. 5. Stop the chronometer when the parachute hits the ground to measure the falling time....