08:25Hey You What If?Series 1You Took All the Water Out of the Sea?CBBC Thu 11th Feb 2021, 08:25 on CBBC ChannelAvailable for 6 monthsEmpty the oceans and you’d see hidden wonders, but you’d also cause the end of the world. GenresChildren'sFactualFactualScience & NatureBrandHey You What If?SeriesHey You What If?: Series 1 Source: BBC Online