We use sound and spelling cards, with pictures, in the classroom to help students relate sounds, letters, and spellings. The picture for one of the r-controlled vowels is "earth" .
The week I introduced this sound, we were trying to brainstorm some words that use this sound. One little buddy said, "Hey, Earth is like Urmston." We decided that it should no longer be called the "earth" card, but now we would call it the "Urmston" card. If we were sounding out the word "burn", to read or spell, in sound-card lingo it would be: Beiber-Urmston-Nurse. Of course we had to put an Urmston picture on the card. Later, I sneaked into some other classrooms and put Urmston pictures on their earth cards.