The difference between continuous and continual
TLDR: Continuous means something that’s going on without interruption (like Earth rotating). Continual means something that happens again and again without long pauses in between (a tap dripping).
While these two words might seem to mean the same thing, their definitions actually overlap less frequently than you might imagine.
continuous (adjective)—unbroken entity; without exception or interruption
We need to edit the footage because it was recorded in one continuous take.
The continuous advance of the enemy forces was marked upon the map.
The patient was suffering from continuous pain in the lower back.
continual (adjective)—a series of actions or events that recur frequently; without interruptions
The fortress fell after a night of continual bombardments from the infantry.
The experiment was delayed due to continual blackouts.
Patricia suffered continual bouts of coughing on Sunday.
As you can see, both continuous and continual share the meaning ‘without interruption’. However, I personally feel that continuous sounds better when used in this context. In comparison, continual is more usually synonymous with an event recurring frequently with only short interruptions rather than without any interruptions at all.
Another point which separates these two terms is that continuous can be used in reference to space as well as time. For example:
Hadrian’s Wall created a single continuous barrier from Segedunum to Bowness-on-Solway. (Space)
The couple have been in a firm and continuous relationship for five years. (Time)
Though it might be a bit tricky to determine which term to use, just remember that continual refers to a series of frequently recurring events—such as a day being peppered by showers or storms—and continuous refers to something that appears to go on without any interruption—such as water flow from your tap (or most speeches by your principal at school assemblies).