Development of a research instrument for environment-minded behaviour of children aged 9 to 12 years. Name of residence / group / several hypothetical situations with environmental aspects and-or values and belief aspects in which the pupil has to choose for "do" or "don't" on a 4 points scale / questions about knowledge of recycling, chemical waste, use of bottle bank, wastepaper / own influence on environmental problems / environmental attitude of parents, separation of waste and refuse, use of energy and water. Background variables: basic characteristics/ residence/ occupation/employment/ organizational membership