When wind or different disturbances detach winged maple seeds referred to as samaras from their dad or mum tree, they spin by means of the air – and may even spin when it’s raining. Impacts by high-speed raindrops solely briefly interrupt the seed’s spinning as a result of the seed can shed the drop quickly and restart its spinning in much less time than it takes to blink.
If you happen to dwell someplace with maple bushes, you’ve most likely seen their hanging helicopter seeds – made up of a seed pod connected to a fragile wing. Maple samaras’ distinctive design and spinning motion can train physicists like me about seed dispersal patterns and even engineering new varieties of flying autos.
The samaras’ spinning motion, referred to as autorotation, retains them within the air for longer in order that they journey farther.
The spinning flight of a maple samara.
In a February 2025 examine, my colleagues and I filmed raindrops as they crashed into autorotating samaras. The samaras shed drops by shattering them, flinging the drops off, or rolling out of the best way – like they’re turning away from a punch. If a drop falls in simply the appropriate place, the spinning seed can lower it in half.
The motion of a samara because it spins by means of the air. Our new examine captured this sample utilizing a high-speed digital camera.
Breanna Shaeffer and Andrew Dickerson, College of Tennessee-Knoxville
So as to maintain flying, the samaras should shed the whole drop. Samaras shed drops quickest when the drops hit the heavier, spherical nutlet a part of the seed, somewhat than the wing. Shedding is made simpler by the samaras’ mildly water-repellent floor. We estimated that raindrop collisions cut back a samara’s time in flight and the space it travels whereas spinning, however by lower than 10%.
Why it issues
Maples are an necessary species to the Japanese United States. They supply syrup and timber, making them economically and commercially vital.
To proliferate in a quickly altering local weather, maples and different samara-bearing species must disperse their seeds so far as potential.
My group’s outcomes present context for different research centered on how wind transports rotating and nonrotating seeds alike. Some seeds may even journey a whole bunch of miles.
From an engineering perspective, the insights gained from our examine might inform the design of latest varieties of aerial autos that use autorotation to experience the wind with no motor. Mimicking the shapes of those seeds might assist such autos shortly get better from disruptions to flight.
Samaras are additionally visually intriguing. Discovering extra about how small, stunning elements of nature thrive might assist scientists get individuals within the surroundings.
What nonetheless isn’t recognized
Maple samaras signify only one method that seeds use the wind to disperse farther. A dandelion’s parachute-like float depends on the seed’s gentle weight and excessive drag. A hop tree seed makes use of a single, wafer-shaped seed to flutter, whereas triplaris seeds have three wings that obtain a helicopter-like spin. Researchers nonetheless aren’t certain how raindrops can have an effect on the flight of those seeds.
What’s subsequent
Subsequent, my colleagues and I hope to unravel the flight mechanics of the “rolling samaras” discovered on tulip poplar and ash bushes. These seeds rotate like maple samaras, however the wing additionally rolls across the axis that runs throughout its wingspan because it does so.
Not solely will we plan to match their flight efficiency towards the extra recognizable maple samara, however we will even examine how these seeds reply to perturbations corresponding to wing harm and crosswinds.
How I do my work
I prefer to uncover the complexity in seemingly easy programs. So most of the temporary, small and customary interactions in our world are splendidly stunning. I search to inform these tales by means of a digital camera lens and with mathematical aptitude.