23. There are more molecules in a cup of water than cups of water in the oceans – Earth’s oceans contain approximately 1.3 billion cubic kilometres (312 million cubic miles) of water, which equates to 5.2 x 1021250-millilitre cups. A cup of water, meanwhile, contains a jaw-dropping 8.4X1024 H20 molecules – that’s over 1,000 times more molecules than cups!