See the below pictures of Chia Seeds in water.
The bottom left picture is dry chia. The top left picture is chia that has been exposed to water. The two right pictures are chia suspended in water!
Chia seeds grow 9-10 times their size when exposed to a liquid, and as seen in the top left photo, chia seeds form a gel layer too.
This feature is great for hydration! Chia will slowly release the water during digestion.
This feature is also great for feeling fuller!