The slinky is simply a spring. When a spring is stretched, tension tries to pull it back together towards a collapsed state. The spring’s tension is occurring mostly symmetrically, so it pulls all ends towards the center. When dropped vertically, the bottom end is trying to fall down, but tension acts in the opposite direction, so the bottom of the spring remains stationary.
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California Sinking Faster Than Thought, Aquifers Could Permanently Shrink
“Because of increased pumping, groundwater levels are reaching record lows — up to 100 feet (30 meters) lower than previous records,” Mark Cowin, director of California’s Department of Water Resources,said in a statement. “As extensive groundwater pumping continues, the land is sinking more rapidly, and this puts nearby infrastructure at greater risk of costly damage.” [It’s Raining Spiders! The Weirdest Effects of California’s Drought]
What’s more, this furious groundwater pumping could have long-term consequences. If the land shrinks too much, and for too long, it can permanently lose its ability to store groundwater, the researchers said.
The state’s sinking isn’t new: California has long suffered from subsidence, and some parts are now a few dozen feet lower than they were in 1925, according to the U.S. Geological Survey.