xUmp.com Logo

Solar Radiometer (Image One) @ xUmp.com

Solar Radiometer

by Tedco   Item#: 10094   5 star rating 6 customer reviews
List Price:$19.99
Price: $14 /each
You Save: $5.99 (29%)
IN STOCK Ships next business day.
Add to cart to see shipping prices.


Save additional 5% OFF with coupon code: SAVEFIVE

The vanes, or wings, in this solar radiometer are alternately dark and light in color. When the light strikes these wings it transfers heat to each one - but not at the same degree. The lighter wing reflects the rays and the darker wing absorbs. The stronger the light, the more energy there is to heat up the darker side of the wing causing the wings to spin faster. It spins under the solar light or a regular light bulb. Great for science projects, as a gift or as a desk amusement!


  • Uses heat transfer to spin
  • No batteries required; the radiometer is powered entirely by light
  • Either solar or indoor light works
  • Great desk toy
  • Great for solar science lessons

8 +
Box Size:
5.25 x 3.25 x 3.25 inches
13.34cm x 8.26cm x 8.26cm
0 lb 3 oz
0.08 kg

Customer Reviews

5 star rating  directly observable interesting physics
Mark ODell from USA, CA, Los Angeles
Motion directly from light never gets old. This motion, however, is not due to photon momentum radiation pressure, or the direct pressure from gas warmed by the black faces. Such simple explanations turn out to be wrong. This is a light-driven heat engine. Even James Clerk Maxwell initially disagreed with Osborne Reynolds about the mechanism, so we are in good company watching and wondering. See Wikipedia Radiometer references for a lucid discussion, but know there is much more going on than the common explanations most of us learned when first seeing a Crookes Radiometer ("light-mill"). Cooling causes direction reversal. Improving the vacuum stops motion altogether. Radiation pressure is real, but the effect is too small here. The important mechanism has more in common with the flow of heat or superfluid helium than the momentum of photons or the pressure of bulk hot gas. The black sides do get hotter, but the ultimate magic of motion apparently happens at the edges of the vanes, not the faces.

5 star rating  Good Classroom Tool
Cynthia from USA, UT, Draper
This is an awesome way for students to learn that solar radiation is a form of energy.

5 star rating  Radiometer fun
Maria from Cedar Rapids, IA
Love to watch this work and think about the science behind it. Great tool for teaching about energy.

5 star rating  Great Conversation Piece!
Eric Holmes from Moose Jaw, Canada
Everyone that sees it will stop and look at it rotating and then will have a theory on what makes it rotate.

5 star rating  SolarRadiometer
Joan from Tulsa, Oklahoma
This is so fun. I broke my mother's radiometer, so had to replace it. A good price for a great product.

5 star rating  

intriguing, fun


Snap Circuits Green.


Snap Circuits Green

Teach your students about green energy sources in a creative way with this fun kit!

4D Vision Triceratops Model.


4D Vision Triceratops Model

This unique 4D triceratops model is a must-have for the dinosaur fan in your family!

21 inch Galileo Thermometer.


21 inch Galileo Thermometer

This top of the line 21 inch tall Galileo thermometer features 10 floating spheres.

Neon Pin Art.


Neon Pin Art

This fun neon pin art features blacklight sensitive pins!

Real Scorpion USB Mouse.


Real Scorpion USB Mouse

This mouse includes a real scorpion mounted on the inside of it!

CHEM C500 Chemistry Set v2.0.


CHEM C500 Chemistry Set v2.0

Get this great introductory chemistry kit for your favorite young scientist!

xUmp.com Logo


xUmp.com is a leading internet retailer of scientific educational supplies, toys and gifts. Founded in 2003 and located in California. Follow us:

Become our Friend on Facebook Follow us on Instagram  See our Videos on Vine Follow us on Twitter Check out our videos on YouTube


Sign-up for our weekly discounts and promotions email newsletter.