Why is the sea salty?

1. 1

   Wobble says

   Rocks have tiny bits of salt hidden inside them. When rain falls on the land, it slowly wears the rocks away and washes some of that salt out. Streams and rivers carry it all the way down to the sea. So bit by bit, salt from all over the land ends up in the sea.

   For ages 4–7
   Hear Wobble

   Checked against Why is the ocean salty? (NOAA Ocean Service)

2. 2

   Why does the salt stay in the sea?

   The sun warms the sea, and some of the water floats up into the air as invisible vapour. The salt can't float up with it, so it stays behind. Rivers keep bringing more salt, and the sun keeps lifting water away. That's how the sea stays salty.

   For ages 6–9
   Hear Wobble

   Checked against A decade of sea surface salinity (NASA Scientific Visualization Studio)

3. 3

   Does all the salt come from rivers?

   Deep down, the seafloor has cracks in it. Seawater seeps into them and gets heated by hot, melted rock far below. The hot water picks up minerals from the rocks, then gushes back out through openings called vents. So some of the sea's salt comes from under the sea itself.

   For ages 8–11
   Hear Wobble

   Checked against Why is the ocean salty? (NOAA Ocean Service)

In Lil' Phil, reaching the bottom of this wonder earns a sticker for Wobble's collection.

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