Throw a stone across a sheet of fresh lake ice and you may hear something that sounds more like a space battle than a winter walk: a run of bright "pew" and "zing" notes that slide downwards in pitch. The effect is real and has a tidy explanation. The ice acts like a huge, thin plate, and the high-pitched vibrations travel through it faster than the low ones, so they reach your ears first.
The sound became famous in autumn 2014, when YouTuber Cory Williams, known online as "Mr. Safety" and for his channel DudeLikeHELLA, filmed himself skipping rocks on a frozen lake near Anchorage, Alaska. His delighted reaction and the strange chirps went viral, and an acoustics professor stepped in to explain the physics.
The video that made the sound famous
Williams had moved to Anchorage a few months earlier, in 2014, and was documenting his first months in Alaska in a video blog. On one outing he and his girlfriend found a lake with a thin, clear skin of ice, and he started tossing stones across it. Each throw produced a burst of electronic-sounding pings. "This is the coolest sound I've ever heard!" he shouted on camera, and many viewers agreed.
The rock-skipping section comes a few minutes into the vlog. Listen for the pattern: a sharp tick at the moment of impact, followed by a falling whistle that seems to race away across the lake.
The physics: ice as a giant drumhead
When a stone strikes solid ground, most of its energy is soaked up in a dull thud. A floating ice sheet behaves differently. Because there is liquid water underneath rather than rock, the ice can flex up and down, much like the skin of a drum or a struck cymbal. Canada's Cottage Life magazine used exactly that comparison when it explained the pings people hear on frozen lakes.
Mark Hamilton, a professor of acoustics at the University of Texas at Austin, went further in an interview with Live Science in October 2014. He described the impact as sending a bending wave (also called a flexural wave) through the plate of ice. That wave moves faster than sound travels in air, and as it spreads it continuously leaks sound into the air above.
Why the pitch slides downwards
The key is a property called dispersion. In a thin plate, waves of different frequencies do not travel at the same speed: short, high-frequency waves move faster than long, low-frequency ones. A single sharp knock contains a mix of frequencies, and as the disturbance travels across the ice those components gradually separate. The high notes arrive first and the low notes trail behind, so you hear a descending sweep.
Hamilton compared the result to a musical gesture: "It's as though you ran your finger from right to left across piano keys." He also pointed out that distance matters. Right next to the impact the frequencies have not had room to spread out, so all you hear is a crack. The chirp appears only when the wave has travelled some way before the sound reaches you.
The same sound in Star Wars
If the noise reminds you of laser guns, there is a reason. According to Hamilton, the blaster effects in the original Star Wars films were created with the same physics. Sound designer Ben Burtt hit a guy wire on a radio antenna tower with a hammer, and the tensioned steel cable dispersed the strike into that famous "pew". Long springs, such as a stretched Slinky, do the same, which is why toy and classroom demonstrations of "laser sounds" often use them.
A moment from Williams' Alaska vlog. The thin, clear ice in the background is what makes the singing sound possible.
Why some ice sings and some doesn't
Not every frozen lake will give you a sci-fi soundtrack. Cottage Life notes that clear ice, which forms during cold, still nights without snow, produces high, ringing tones. Snow ice, the cloudy white layer that forms when snow on the surface becomes soaked and refreezes, gives lower, duller sounds because its fine grains absorb some of the vibration.
Thickness plays a part too. Thinner sheets flex more easily and tend to produce the most dramatic chirps, which is one reason the effect is common in early winter, soon after a lake first freezes. Large lakes also make other noises on their own, from groans to deep booms, as the ice expands and contracts with changing temperatures. Those cracks do not necessarily mean the ice is getting weaker, but they are a reminder that it is constantly moving.
Safety first: listen from the shore
The best singing ice is often the thinnest, and that makes it the most dangerous to stand on. You can enjoy the sound perfectly well from the bank. If you do plan to go out on a frozen lake, local guidance is worth knowing. The Minnesota Department of Natural Resources, for example, advises:
- Stay off new clear ice that is thinner than about 4 inches (10 cm).
- Around 4 inches of solid, clear ice is the minimum for walking or ice fishing.
- White or snow ice is only about half as strong as clear ice, so the thickness should be doubled.
- Thickness can vary dramatically across one lake, because currents, springs and snow cover all affect it. No ice is ever completely safe.
Check with local authorities, carry ice picks and go with a companion. A video of a rock skipping across a lake is not proof that the surface would hold a person.
Try it, safely
If you live somewhere with cold winters, the experiment is easy. Choose a pond or lake that has just frozen over, stay on the shore, and throw a small, flat stone so that it skims rather than plunges. Then stand still and listen. The further the stone travels before you hear it, the clearer the downward sweep becomes.
The lesson Williams stumbled on is a nice one: ordinary materials can behave in surprising ways once they are thin and stretched, and a few seconds of curiosity on a cold day can lead straight to the physics of waves, musical instruments and film sound design.
Explore the related article: Sounds of Space: Signals Turned Into Audio.
Sources: Live Science, 16 October 2014: interview with Mark Hamilton; Cottage Life: noises made by a frozen lake; Minnesota DNR: ice thickness guidelines. Video: Cory Williams (DudeLikeHELLA).
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