Plants, episode 1: seeds

In education, I belong to the “hands-on” branch of science didactics. Different terms are used to name this pedagogical approach whereby students are introduced to scientific concepts and thinking from activities of investigation, observation of phenomena, manipulation of materials and reflection on their actions.

I therefore propose here to combine school gardening activities with plant study activities. This article and the one that will follow fall short of covering the whole subject. Rather, they are examples to arouse the interest of students.

Warning : Commercial seeds sold for gardening are often covered with fungicide. It is preferable to avoid having them manipulated by the pupils. For these activities, obtain the edible seeds available, among others, in grocery stores and health food stores.

The discovery of seeds

This is a fall activity where students go on a seed hunt. It is good to have them work in pairs so that they collect together as many different seeds as possible. Back in class, students are encouraged to classify their seeds according to color, size, shape, etc. They can also explore the behavior of these seeds in water: do they float or sink? Students formulate a hypothesis that they need to justify and then verify. Then, they write down or draw their approach in a science notebook.

The activity on the seeds ends with the making of a mural in which all the students participate and which is displayed in the hallway. This type of closing activity makes it possible to move from STEM (Science, Technology. Engineering, Mathematics) science education to STEAM where the A stands for the Arts.

Is the tomato a fruit or a vegetable?

To answer this classic question, it is important to take into account the context of use of the tomato. In food, any plant that is generally eaten salted is called a vegetable. However, in botany it is quite different. Vegetables are only the plants of the fabaceae group, the seeds of which are found in a pod: peas, beans, lentils, chickpeas and all these red, white or other beans. However, what we eat are the fruits of these plants. The fruit is the organ that serves to protect the seeds of plants before they reach maturity.

The fruit is an organ of a flowering plant and some of them are edible. With the students, why not do a seed hunt for edible fruits: cucumber, pepper, avocado,… do strawberries have seeds? What about bananas?

Seed dissection

Large seeds such as beans or lima beans should be chosen. It is then necessary to soak the seeds in water for at least 24 hours, in order to soften the seed coat, that is to say the envelope which covers the seed. Distribute a few seeds to each student and invite them to gently pry open the seed. What do they discover?

I recommend the use of small magnifying glasses to observe the seedling well.

Germinate the seeds

here is a video of a few minutes which explains how to go about germinating the seeds for the purpose of eating the shoots. This activity is very easy to do.

You can even save sprouted seeds at all times in the classroom and allow students to eat them as needed.