Weather Forecast


Weather Talk: Tides are just gravity at work

All of the talk of the lunar eclipse this week created some discussion of the tides.

There are a lot of common misconceptions about tidal forces. Tides are not some mysterious, special force that only acts on water — tides are just a byproduct of gravity, which is created by extremely massive objects and is regulated by distance.

The moon exerts a gravitational pull on the Earth, pulling the solid body of our planet slightly toward the moon. On the side facing the moon, the liquid ocean is pulled a little more than the rigid Earth, while the ocean on the side facing away from the moon is pulled a little less.

This creates two bulges in the ocean, one on the side nearest the moon and one on the opposite side. This explains why the ocean has two high tides and two low tides each day while smaller bodies of water, like lakes, rivers or a human brain, are unaffected.

John Wheeler

John was born in Baton Rouge, LA, and grew up near Birmingham, Alabama. As a teenager, his family moved to Madison, Wisconsin, and later to a small town in northeast Iowa. John traces his early interest in weather to the difference in climate between Alabama and Wisconsin. He is a graduate of Iowa State University with a degree in meteorology. Like any meteorologist, John is intrigued by extremes of weather, especially arctic air outbreaks and winter storms.  John has been known to say he prefers his summers to be hot but in winter, he prefers the cold.  When away from work, John enjoys long-distance running and reading.  John has been a meteorologist at WDAY since May of 1985.

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