Light Mill


Light Mill

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This physical and technical miracle shows you in a clear way how sunlight is converted to energy. Place near a window or under incandescent light and watch as the vanes rotate.
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Origin Germany
Dimensions 9.75 x 3.75 Inches
Material Glass

This captivating physics toy transforms light into action. Invented in 1873 by the chemist Sir William Crookes as the by-product of some chemical research, the radiometer is made from a glass bulb with a set of four two-tone vanes inside. All the air has been removed from bulb which creates a partial vacuum and allows vane to rotate freely on a central spindle.

When exposed to sunlight, artificial light, or even heat, the vanes begin to spin—the dark sides retreating from the radiation source and the light sides advancing.

Experiment with different energy sources to watch the interior of the Light Mill spin faster or flower. For those who don't know the science of how a radiometer works, the movement can seem inexplicable. A simple explanation may seem to dispel the mystery but the more deeply you think about the thermodynamics at play, the more profound the wonder becomes.

Shipping & Returns

Our products ship through a privately owned climate-controlled warehouse in San Diego, California.

We offer a variety of shipping methods from budget-friendly to price-doesn’t-matter. You can compare estimated costs and transit times once you begin the checkout process and enter your shipping address. Carrier options may vary based on your destination.

We strive to pack and ship all items within 24 hours of each order (Monday through Friday). However, we are a small team so during peak holiday season we kindly ask that you allow 3-5 days for your items to be sent on their way. Every box shipped from Art of Play is expertly packed by actual human beings (you can see their names written on your package slip). Everyone in our warehouse is paid a fair wage and treated with respect.

Return Policy

We will gladly offer a refund or store credit in exchange for any items returned within 30 days of the original order, as long as the items are still sealed in new condition. We cannot accept returns of opened or used items. Return shipping is the responsibility of the customer.


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