@CNN: Ice skaters recorded this frozen lake in Norway ‘singing.’ The unusual frequencies are often a result of changing temperatures shifting the ice. https://t.co/ZxQ5NuSfXV https://t.co/V495BqJft0

@CNN: Ice skaters recorded this frozen lake in Norway ‘singing.’ The unusual frequencies are often a result of changing temperatures shifting the ice. https://t.co/ZxQ5NuSfXV https://t.co/V495BqJft0