Sideways Icicles

Icicles on a roof growing sideways because of prevailing wind currents demonstrates that the applied wind force partially overcomes the gravitational force downward.

Image

Farley

Iowa Core Standard

HS-PS2-1

Analyze data to support the claim that Newton's second law of motion describes the mathematical relationship among the net force on a macroscopic object, its mass, and its acceleration

Driving Question

What forces are involved in the direction of the icicles?

Probing Questions

How long were the forces affecting the icicles?
Why did the phenomenon occur here but not elsewhere?

Classroom Suggestions

Students could:

Complete a notice and wonder activity using the photos. Enlarge the phenomenon photo and zoom in on the icicles for a closer look or to measure angles.
To focus on forces, use the Sideways Icicles Video clip showing the wind pattern on the building.

Resources

Wonderopolis | How Are Icicles Formed: This page, written for students, describes how icicles are formed.
Kinematics in Two Dimensions | An Introduction: This lesson explains how motion can be described as made up of vertical and horizontal components. It also features links to other resources, and is suitable for teacher background or a physics class.
The Physics Classroom | Addition of Forces: This article explains the process of adding vectors to find the net force. It also features links to other resources, and is suitable for teacher background or a physics class.
The Physics Classroom Vector Addition Interactive: This lesson contains teaching notes and a link to an interactive to help teach addition of vectors. Students can insert the vectors involved and it will give the resultant magnitude and angle.
Colossal | Spectacular Ice Formations Atop a Windswept Mountain in Slovenia: Photographed by Marko Korosec the extreme conditions of humidity, freezing temperatures, and high wind created ice formations that are nearly horizontal.

Contributors

Submitted by Diane May.