Task 3

Materials and tools for a working group:

balloon, wooden spoon, metal spoon, plastic spoon, foil, plastic bag, cotton fabric, wool fabric, paper confetti

In the second task, the pupils tried a procedure by which it is possible to compare the intensity of electrization of the balloon by its differently long rubbing on the same surface. They will also use this procedure to „measure“ the difference in how various materials can be electrified by the same rubbing. To maintain experimental conditions, it is important to develop a process in which we eliminate the impact of different variables on the outcome of the investigation. As one of our intentions is to develop competence to propose our own way of validating predictions, we are encouraging pupils to try to design their own way to find out if different substances (listed in the table in task 3) create different intense electrification , which will lead to attracting more paper confetti. .

In the discussion of the examination procedure, the teacher ensures that all the materials studied are always on the same surface, such as a carpet, to be rubbed for the same length of time and that the surface is of the same size. This can be ensured by first examining the wooden spoon and then wrapping it with different materials.

Before exploring, pupils can make predictions about which material will cause more intense electrification. Predictions can be made by determining the order of materials from those that they think will cause the least electrification to those that will cause the most electrification. In the table, there are also two free columns available for pupils to indicate materials they would like to review.

Then they carry out an observation in which they try to follow the set examination procedure as precisely as possible. They repeat the measurement for each material, or check their results with the results of other groups and repeat the measurement only if they have obtained very different results for a particular material. Based on the results of the measurement, they formulate a conclusion stating whether the degree of electrification depends on what material the objects has been rubbed against. When making the conclusion, they refer to their findings (measured values in the table).