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SKU #TOP-415
Availability: In Stock
Shine a light on this spinning disc to make spiral patterns and more!

AAA Alkaline Batteries - Pack of 4

Availability: In Stock
AAA Heavy Duty alkaline batteries. Sold in packs of 4.


The PhoTOP consists of a flat disk 12 cm in diameter and a two-part aluminum spindle. The resulting spinning top has phosphorescent paint on one surface and instructions for its use on the opposite surface. It is intended to be combined with a near UV/deep purple 405nm laser pointer (included) - though part of the fun is experimenting with other light sources, even a smartphone light.

When the top is spun, the UV or other light source is pointed at the spinning top's phosphorescent surface, resulting in green luminescent spiral patterns, as well as Lissajous and other figures. It is a mesmerizing piece of kinetic art, a toy or plaything for the amusement of children and the young at heart, and an educational apparatus to illustrate principles of quantum mechanics and phosphorescence, as well as principles of pattern formation. Requires 2 AAA batteries (not included).

The PhoTOP has undergone extensive testing to meet all US safety standards. (It is intended for use by adults or children older than three years of age because of the possibility of swallowing the spindle by younger children.) The PhoTOP and its inventor, Kenneth Brecher, Professor of Astronomy and Physics, Emeritus at Boston university, have been featured in several online publications, including Gizmodo.
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2 reviews
Review star icon Review star icon Review star icon Review star icon Review star icon Dec 12, 2023
Wow! Everybody (age 10 to age 78) who sees this can't stop playing with it and wants one. And there is a huge amount of atomic physics one can talk about. And for $20 bucks it comes with a violet laser. I rate it at 5 stars only because that is as high as I can go! P.S. I taught physics for 30 years.
Charles Hunt
Owner Response: We're so happy you're enjoying your new purchase!

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Mesmerizing Top!
Review star icon Review star icon Review star icon Review star icon Review star icon Feb 7, 2023
My preschool students and I LOVE the PhoTop!! The phosphorescent surface glows a soft green in the dark. When the near-UV purple pen laser is shone on the top, a bright green line appears! The light can "draw" scribbles or shapes when the top is at rest. The top is a tad difficult to get spinning, but when you do, and shine the laser at the disk, WOW! The initial bright design fades fairly quickly, so bright new designs can be made continuously. I would highly recommend!
Kristin Malara

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This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.

Elementary Middle School High School


Students can use this tool to make observations to construct an evidence-based account that objects in darkness can be seen when illuminated.


Students can use this tool to formulate mathematical representations to describe a simple model for waves that includes how the amplitude of a wave is related to the energy in a wave.


Students can evaluate evidence and reasoning behind the idea that electromagnetic radiation can be described by a wave model or a particle model.


Students can use this tool to communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy.

Suggested Science Idea(s)


Students can use the PhoTop as an educational tool to help them make observations and collect evidence illustrating simple principles to help explain how objects illuminate while focusing on wave patterns.


* NGSS is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, this product.

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