The youngsters, from nine schools, also embarked on treasure hunts around the grounds hunting for clues "auf Deutsch", and learned about Germany, Austria and Switzerland on the net.
It is the second time the high school has run the three-day programme, as part of its involvement in a national pilot promoting modern foreign language teaching in primary schools. In September, the same pupils will receive weekly French lessons from Whitchurch teachers. When they finally arrive at the high school, in 2006, they will have had experience of both languages.
Mrs Carter said: "You have to be slightly mad but it's really great.
There's a lot of speech and visual material, not a lot of reading. You can have more fun, it's more flexible because you are not bound by the curriculum."
Evaluations of the French lessons and German days have produced only two negative responses from 168 parents, while pupils' confidence has improved, along with their perceptions of the high school, according to Lyn Mills, Whitchurch's head of curriculum and herself a French and German teacher.
"The beauty of it is that it's also a transition project," she said.
It has also provided staff development opportunities for teachers in both sectors. Whitchurch is hoping primary colleagues are picking up useful experience, expertise and materials for teaching modern foreign languages themselves, while its own language teachers have adjusted and targeted their teaching methods to better suit the needs and enthusiasms of younger children.
John Tobutt, head of 330-pupil Gabalfa primary, took 35 Y5 pupils to last week's German days.
He said: "It helps us dramatically with the transition to key stage 3. The children work with a new range of teachers and they are learning a foreign language for the first time.
"My view is the younger you tackle a foreign language the better. The only difficulty we have is the national curriculum at KS1 and KS2 is very over-subscribed. You can't keep pouring more water into an overflowing tub."