The following experiment describes an easy experiment for children 11-12 years old, performed during spring in a compulsory school near Karlstad, Sweden. Four different ripe fruits were placed under flowering plants of Impatiens New Guinea (Impatiens hawkeri) for four days on a table and with plastic bags around both plants and fruits. For one of the ethylene-producing fruits, apple, the result was very clear. The plants shed many flowers and buds on the first day, due to stimulated senescence caused by ethylene. For the other ethylene-producing fruit, kiwi fruit, the result was clear but not as explicit as for apple. On the other two fruits, orange and lemon, flowers and buds were shed in the same proportion as the control plants. From these results a discussion could focus on tips on how to stimulate the ripening of unripe fruit e.g. by putting apples in the same dish. The experiment is planned in a formal scientific manner and thus stimulates discussion about how to design experiments. Very few materials are required - just flowering pot-plants, fruits and plastic bags. These are easy to buy in a garden centre or a shop. Furthermore, the experiment is cheap, it is easy to perform and it stimulates practical work.
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