I need your corrections

Please I need your corrections on the following paragraph :
The Water Cycle
First, the sun heats the water of the sea. Then, tiny drops evaporate and rises up into the sky to form clouds. Next, when the clouds become heavy, rain falls. After that, some of water drains undergrounds and moves slowly downhill over hard rocks to the sea. Finally, we use water for drinking, cooking, washing and irrigating.

The Water Cycle

First, the sun heats the water of the sea. Then, tiny drops evaporate and rise up into the sky to form clouds. Next, when the clouds become heavy, rain falls. After that, some of the water drains underground and moves slowly downhill over the rock layer to the sea. During this cycle, we use water for drinking, cooking, washing and irrigation.

From a grammatical point of view:
The Water Cycle
First, the sun heats the water of the sea. Then tiny drops evaporate and rise up into the sky to form clouds. Next, when the clouds become heavy, rain falls. After that some water drains underground and moves slowly downhill over hard rocks to the sea. Finally, we use water for drinking, cooking, washing and irrigation.

From a scientific point of view, you have only used the one scientific term ‘evaporate’. You might want to include the other basic terms relating to the water cycle: condense/condensation, precipitate/precipitation. You might also wish to consider that it is not only the water which drains underground that moves toward the sea. You have made no mention of the part played by overground surface runoff in rivers and streams. You have also not indicated that the process is cyclical and starts again.
A more advanced paragraph would include such aspects as surface runoff, whereby the water evaporates off other surfaces and does not reach the sea.