This two-headed fan does more than cool you off - it delivers a dazzling lesson in persistence of vision! Each fan blade contains five colorful LEDs that flicker at different speeds, giving the illusion of streams of light instead of individual dots. (This is the same principle that turns a sequence of still images into a motion picture.) Turn it on and enjoy a double light show in red, green, yellow, and blue. Better still, give the blades an extra spin to increase the speed of the rotating arm so that the two individual fan patterns merge into a larger, ever-changing geometric design: triangles, loops, spirals, and more! We guarantee you haven't seen a persistence of vision device like this before! Requires 3 AA batteries (included).
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May 19, 2018 | By Susie of Ignacio, CO United States
Owner Response:Susie, That certainly shouldn't have happened. Someone from our Customer Service Department will be reaching out to you to replace your Fan.
Mar 26, 2018 | By ALLEN of PRINCETON JUNCTION, NJ United States
Jan 21, 2018 | By DeEtta Lorick Andersen of Center Point, IA United States
Jan 2, 2018 | By J. Hemel of Portland, OR United States
Nov 30, 2017 | By Michelle of Stillwater, MN United States
Owner Response:We apologize for the faulty fan blade. Customer service will be in touch to make your order right for you!
There is more to this than it looks...
Aug 26, 2016 | By Mark Carter of phoenix, AZ United States
This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.
Suggested Science Idea(s)
| Elementary || || Middle School || || High School |
| 1-PS4-2 |
Students can use the Persistence of Vision Double Fan to make observations to construct an evidence-based account that objects can be seen only when illuminated. 2-PS1-1
Students can use the Persistence of Vision Double Fan to plan and conduct an investigation to describe and classify different kinds of materials by their observable properties. K-2-ETS1-2
Students can use the Persistence of Vision Double Fan to develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem. 4-PS4-2
Students can use the Persistence of Vision Double Fan to develop a model to describe that light reflecting from objects and entering the eye allows objects to be seen. 4-LS1-2
Students can use the Persistence of Vision Double Fan to use a model to describe that animals receive different types of information through their senses, process the information in their brain, and respond to the information in different ways.
| || MS-PS4-2 |
Students can use the Persistence of Vision Double Fan to develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials. MS-LS1-8
Students can use the Persistence of Vision Double Fan to gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate storage as memories. MS-ETS1-4
Students can use the Persistence of Vision Double Fan to develop a model to generate data for iterative testing.
| || HS-PS4-3 |
Students can use the Persistence of Vision Double Fan to evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described either by a wave model or a particle model, and that for some situations, one model is more useful than the other.
The loopy and colorful patterns of this fan are dependent on the 'persistence of vision' phenomenon: when the eye and the brain work together to create an illusion of a whole image. Hold the illuminated fan stationary so students can see the structure.
By tapping the fan with the edge of your hand, the LED lights will change patterns. The wave patterns formed by this action are a foundation for a vast array of investigations.
* 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.