Make a sandy ‘beach’ in the box and add the shallow ‘sea’. Switch on the lamp (‘Sun’) and wait for a few minutes for the water to become warm (or ‘cheat’ by adding warm water from the kettle). Add the freezer pack to cause the effect of cooling air which will form ‘clouds’. After a time, the water droplets that condense on the underside of the box lid beneath the cool ‘clouds’ grow, and fall to the beach as ‘rain’.
This is one of many 'watery ELIs; other ideas can be found on the website in Teaching strategies.