The Journey of Electricity

Where is electricity produced? How do we get electricity?

This activity is intended for students to get closer to the raw materials or natural resources from which electricity is obtained, through its transformation, and how all these processes lead to environmental problems. Some resources are inexhaustible, like the sun or the wind. Others, on the other hand, run out with their use, such as oil, gas or coal, and curiously, they are the most used to obtain electricity.

Later, by means of a simple experiment, an electric current will be manufactured from chemical reactions, making an electric battery or homemade battery. To work on the impact on the environment, an investigation will be carried out on the problems generated by discarded batteries.

You will need…

Materials for the construction of homemade batteries, documentation, continuous paper, colored markers and batteries of different composition for each work group.

Organization and development

This activity is organized in three phases. In the first, the raw materials are investigated, thanks to which electrical energy is obtained. The second shows how to create an electric current, thanks to the chemical properties of some materials, that is, how a cell or battery works. And in the third, the problem of contamination generated by batteries when they are discarded is worked on. Finally, an exchange of experiences and ideas will be organized and conclusions will be established around a debate.

When carrying out the experiment it is suggested:

• Invite the students to propose working hypotheses prior to the experiment, what would happen?

• Introduce modifications in the experiment based on the explanations of the students.

• Carry out the experiments in groups of 3 or 4 people, since the exchange of ideas between them will be more enriching.

• Keep the safety rules when handling electrical materials.

• Write down the conclusions and observations made, in notebooks and draw the experiment.

 For the other last stages, it is suggested to also organize the classroom into work groups.

 - Phase 1: Electric Nature

In this first phase of the activity, students are introduced to the sources that allow us to obtain electrical energy.

First, brainstorming is done. To do this, the following question is asked of the entire group: Where do we get electricity from?

Each student has to give an answer, the first one that comes to mind. Once the list is obtained, the class is organized into working groups of 3 or 4 people, and the answers noted on the list are distributed to each group (surely there will be some that are wrong).

They must keep track of that chosen raw material to find out how to obtain electricity, so that they complete the following table. They are informed of the places where the transformations are carried out -the different types of power stations-.

To do this, they must look for documentation in books, encyclopedias, the Internet, ask relatives, etc.

Once the table is completed, the information is organized and the work done is exposed. Continuous paper can be used for this, so that each of the transformation processes is illustrated.

 - Phase 2: Home batteries

You need a wide-mouthed glass jar, a piece of clean copper tubing, a strip of zinc or a metal pencil sharpener, two electrical cords, a glass of vinegar, an LED (light-emitting diode), which is like a very tiny bulb, similar to the ones that light up some Christmas trees, an alarm clock or any other device that works with batteries.

The experiment is set up below:

• The glass jar is filled with vinegar.

• With one end of one of the cables, the pencil sharpener or zinc strip is connected and with one end of the other cable, the copper pipe is connected. Both elements are introduced into the jar with vinegar.

• The free ends of the two cables are connected either to each terminal of the LED or to the two poles of the device's battery holder. Connect the polarity, in the case of the clock, correctly. The positive pole with the copper pipe and the negative with the pencil sharpener or zinc strip.

• What happens to the LED or to the clock?

Describe what happens in the experiment.

• Disassemble an alarm clock or any device or toy that works with batteries, pay attention to the battery holder, what do you observe in it?, how do you know the position in which the batteries should be placed?, why do you think it happens?

Explanation: Batteries have two electrodes that are usually two metals (in our case the zinc or magnesium strip of the pencil sharpener and the copper of the pipe) and an electrolyte, which is the substance that allows electric current to be conducted (in our case is the vinegar). The battery that we are manufacturing has a very low current intensity, so we can only run something that requires very little power, such as the LED.

 - Phase 3: The battery problem

In this phase, the students will be made aware of the environmental problems linked to the consumption of different types of batteries.

To do this, batteries are collected, ensuring that they have a different composition (students can be asked to bring used batteries for their different devices: watches, toys, Walkman, etc.): alkaline, zinc and carbon, silver and zinc, nickel and cadmium, mercury and zinc or lead batteries.

A stack or two can be assigned to each group of male and female students.

Each group should research about:

• The battery that has corresponded to you: brand, type of battery and its composition.

• The polluting effects of said battery on the environment and health.

• What is usually done with these batteries? Are they recycled, recharged or recovered in some way?

To carry out this research, students will search for documentation on the Internet, the press, books, advertising campaigns, etc. about batteries and their problems. Once the information is obtained, the work developed is organized and exposed. For this you can resort to the realization of murals.

A discussion will then take place around the following questions:

• Of the raw materials used to obtain electricity, there are some that have a limited duration, that is, they are used up and are not replaced or this process requires millions and millions of years. On the other hand, others are renewable, that is, they are not spent. Which do you think are renewable and which are not?

• They have seen how a homemade battery can be made and how the consumption of batteries can cause problems, not only for the environment but also for people's health. What other environmental problems do you think are caused by the way we get electricity?

• It is worth discussing the truth or falsity of the following statement, explaining the answer: "All ways of obtaining electrical energy are harmful to the environment and health."