Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Falling Objects, Size, Timing
Name: Laret
Status: educator
Grade: N/A
Location: CA
Country: N/A
Date: 5/20/2005

If two objects of different weights are dropped form the same height, which one will reach the ground first? Why? What is the scientific explanation and how would I teach it to children?

There is a classic physics experiment in which a feather is placed inside a sealed tube. The air is then pumped out of the tube. Next, the tube is turned upside down and the feather falls like a rock.

The acceleration of a falling object in a gravitational field is a constant. It does not depend on the weight, size, or shape of the object. What does depend on these factors (at least on the size and shape) is the drag (or resistance to motion) in the air. In the absence of air, all objects fall at the same rate. In the presence of air the object that is most stream-lined (for equal weights) or the heaviest object (for same shape and size) will hit first.

Greg Bradburn

Click here to return to the Physics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory