Preparation

Like in a real scientific laboratory, the participants will be divided into small groups, each in front of its own container filled with water. Each group will be given a piece of paper and a pencil to note their observations and their objects.

Formulating the hypothesis: object analysis

Each group should draw two parallel lines on the paper to make three columns, which will correspond to three types of behaviour of the objects during the experiment: from left to right: floating, suspension, and sinking. Before the actual experiment, each group will carry out a preliminary phase of analysis during which the materials selected and their composition will be examined: shape, weight, and size. Then they should formulate a hypothesis on the behaviour of each individual object when it comes into contact with the water.

Empirical evidence to verify the hypothesis

Now is the moment of truth: take the object and place it delicately on the surface of the water, observing carefully what happens. Just like Archimedes, who formulated the law by which a body immersed in a fluid, is pushed upwards with an intensity equal to the weight of a mass of fluid of a form and volume equal to that of the part of the body immersed.

Collecting data

As the experiment continues, the students should note the behaviour of the objects when they come into contact with the water: we will obviously see that the heavier objects will go in the "sink" column and the lighter ones in the "suspension" column.

Observations on the experiment

The experiment is much less obvious than what one might think: the shape strongly influences the object's behaviour in water. For example, in the case of wood, but even more so with material like iron, metal alloys, some plastics, and even paper.

Following the first experiment, it is interesting to try the experiment in other environments, like outdoors, and experiment with other natural elements like leaves, branches, stones, grass, petals, and soil.