<P> The main patterns in the tides are </P> <Ul> <Li> the twice - daily variation </Li> <Li> the difference between the first and second tide of a day </Li> <Li> the spring--neap cycle </Li> <Li> the annual variation </Li> </Ul> <Li> the twice - daily variation </Li> <Li> the difference between the first and second tide of a day </Li>

What is meant by spring and neap tides