Worksheet 6: Requirements for life

Teaching aids:

• three small bowls, seeds that germinate quickly (e.g. cress or mung beans), cotton wool, water, saline solution

Procedure:

The teacher gives the students the following instruction for the class project: “Prepare a small “bed of cotton wool” in each of the three bowls for the seeds“

Bowl 1: “Soak the cotton wool in water, add the seeds (cress would be very suitable for this) and leave it to stand for a day or two. If it is necessary, you can add some water. What can you observe?“

Bowl 2: “Soak the cotton wool with the saline solution and add the seeds. What are you observing here after a day or two? Compare your observations with the results from bowl 1!“

Bowl 3: “Soak the cotton wool in water and add the seeds. Replace the water with the saline solution after one or two days. What are you watching?“

Solution: The seeds in bowl 1 germinate very quickly, while nothing happens in bowl 2. The seeds in bowl 3 germinate normally like those in bowl 1, but decay as soon as they are poured with the saline solution.

Explanation: Salt is a hindrance to the growth of most plants. It blocks the process of growth and extracts important nutrients from the soil, which the plant needs.

The result can be an inducement to talk about death as the counterpart of life.

This worksheet enables the students to recognize the importance of appropriate living conditions for living creatures. In addition, they can observe and discuss the transience of life.

Depending on the abilities of the students, they can work in groups or the whole class can do it together. Moreover, the teacher can adapt her/his support individually regarding the state of development and the current knowledge of the students.