Task 7

Materials and tools for a working group:

1.5V or 4.5V battery, 1.5V bulb, 3 wires (eg crocodile clips with cable), nail, spine, coin, foil, ruler, rubber, paper, match, cup

It is clear from the foregoing task that any materials cannot be used for the switch construction. The switch part must be made of an electrically conductive material and a part, conversely, of an electrically non-conductive material. This raises the question of what different materials and where to use the switch. The objective of the task is to determine which materials are electrically conductive and which are not. The teacher emphasizes this research task and leads the pupils to make predictions about the materials found in the table to the task 7.

The verification procedure is specified in the task. It is advisable for the teacher to repeat the principle of electrical circuit formation with the pupils. The table also shows a schematic view that is used as a universal means of communication for scientific communications on electrical circuits. However, it is not necessary for students to have knowledge of schematic representation of electrical circuits to solve the task.

It is advisable that the teacher first demonstrates how the verification will take place, referring to the image in the table. He tries the nail and the pupils see that the bulb is on, so they will indicate that it is a conductive material (or a lit bulb symbol). He then tries another, non-conductive material (which is no longer in the table), such as a cotton swab or sweater. Pupils see that the bulb has not been lit, which means that this material is not conductive (marked with a crossed out bulb or a non-conductive material mark as they agree).

The table is deliberately divided into two parts, with its left part containing only metal objects and the right part containing non-metallic objects. In this way, the communication of the teacher with the pupils in the conclusion of the observation is facilitated. After verifying the predictions, the teacher guides the pupils to try to generalize the conclusion about what materials they are conducting and how they do not conduct electricity.

It should be pointed out from the investigation that only metal objects conduct electric current. There are also other free fields in the table where the pupils will note down the materials they want to explore in order to confirm their observation. Therefore, I will add two more metal and two other non-metallic objects to the table, which they will then examine. The teacher leads the pupils to check their conclusions by studying on the Internet, where it is their task to find out what other substances (except metals) are electrically conductive and also whether all metals are electrically conductive.