Eimear,
Giving children the opportunity to model the boat going over the ocean and disappearing into the distance is a good way for them to directly connect the physical world to the a mental model.
I would delay on including seasons at junior class level, it appears in the curriculum for 3rd/4th class and for 5th/6th class, but very much as an observational activity:
“observe the changing lengths of day and night during the seasons”
At Junior Cycle Students are expected to work with a Sun – Earth model to explain seasons.
See also this article on how seasons are not well understood by many people: