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 Size of Cloud from Shadow
Name: mike
Status: other
Grade: other
Location: N/A
Country: USA
Date: Summer 2011


Question:
I see a cloud and I see its shadow in a field - knowing high sun angles - is there a way of telling how far away the cloud is or how big? - I am thinking if the shadow is 30' wide and the sun is at 2:00 pm- ?


Replies:
Hi Mike,

Try this, draw a small circle representing the Sun. Somewhere below this circle and maybe to the right, draw an oblong, make this oblong bigger than the circle. Now connect the leftmost edge of the circle with the leftmost edge of the oblong with a straight line. Do the same for the rightmost edges. The oblong now represent the shadow of a cloud on the ground, and the lines represent the rays of the sun passing along the edges of the cloud.

Note that you can draw an oblong anywhere in between these two lines to represent the cloud - and depending on its distance from the shadow, can make the cloud very in size.

In order to determine the size of the cloud, you need one more piece of information - where along these two lines the cloud is.

For this exercise, draw two clouds, one close to the "Sun" and one closer to the "shadow". Draw a line from the leftmost edge of the shadow to the rightmost edges of both clouds. Notice that the angles made by these two lines with the leftmost sunray-line are different.

You now have the minimum information you need. ... I love geometry. :-)

Greg (Roberto Gregorius)
Canisius College


Click here to return to the Weather 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 (help@newton.dep.anl.gov), or at Argonne's Educational Programs

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

Argonne National Laboratory