Light and Electricity Activities: Division II

Activity 1: Electricity in our daily lives

Integration Notes:
This is a preliminary activity intended to connect the study of electricity to the Everest 2000 expedition and the work of Dr. Dave Irvine-Halliday through comparing the culture of your students with the culture of the Nepalese people.

Also see the Phase 1 background information on Energy and the Environment, particularly the section on the Pico-Power Nepal Light Project.

Learner Outcomes:
Students will:

• Examine the relevance of electricity in their daily lives.
• Compare their own needs and use of electricity to those of people in Nepal.
• Through research, express informed opinions regarding the potential pros and cons of introducing Pico Power in Nepalese homes.

Materials:

• Copies of a student worksheet, outlined at the end of this activity
• Online resources, as available. Please see the Phase 1 Implementation and Integration notes for Energy and the Environment, Division II.

Introduction:
The electrical requirements of our daily lives are radically different from those of the people in Nepal. Electricity has infused every area of our daily lives, and our absolute dependency on electricity has become an accepted part of our society. Not all countries have the luxury of 'unlimited' electricity. This will be explored with an examination of the Nepalese lifestyle.

Following this study, students are invited to send their informed opinions, regarding the pros and cons of introducing Pico Power in the homes of the Nepalese people, to the education coordinator who will then post them on the Everest 2000 Submissions and Results page.

Activity Instructions:
1. Basic human needs can be categorized into three distinct sections. Discuss these categories as a class until everyone has a good understanding of them.

• Physical Needs - needs related to the body (food, clothing, shelter, transportation)
• Social Needs - needs related to people living together (education, communication, government, laws, class structure, family roles, defense, occupations)
• Psychological Needs - needs related to the mind (religion, art, drama, music, recreation, sports, architecture, literature)

2. Briefly discuss examples from each of the categories, then allow time for students to work in groups to fill in the worksheet with examples that illustrate the importance that electricity plays in helping us to meet our basic needs.

3. Share sheets as a group and discuss the importance that electricity plays in our culture versus other cultures.

4. What about Nepal? How does Nepal use electricity? Do they have access to as much electricity as we do? Find out by viewing an online video where Dr. Dave Irvine-Halliday introduces these issues.

5. In relation to the information provided on the site, along with the students' own research, discuss the potential pros and cons of introducing this basic technology (electricity) into Nepalese homes.

6. You are invited to e-mail informed opinions and ideas regarding this issue to Dr. Irvine-Halliday, via the education coordinator at info@everest2000.ca. E-mails related to this topic must have the subject title: "Nepal Light Project Discussion" - in order to be addressed or posted on the website.

Student Worksheet: create a worksheet with the following headings, leaving space for students' responses.

Physical Needs (related to our bodies) Food Clothing, Shelter Transportation

Social Needs (related to people living together) Education Communication Government Laws Class structure Family roles Defense Occupations

Psychological Needs (related to the mind) Religion Art Drama Music Recreation Sports Architecture literature

Back to: Light and Electricity Activities: Division II

Activity 2: Find electrolytes

Integration Notes:
This activity, together with "Make your own voltaic pile", examines electrochemical principles of batteries (electrolytes and electrodes). With this understanding in place, students will then be equipped to examine the environmental impact of batteries in Phase 2, which will lead to further environmental investigations relating to Nepal later in the project.

Learner Outcomes:
Students will:

• Test a variety of substances and solutions to determine their abilities to conduct electricity.
• Understand how electrolytes can be used as conductors of electricity.

• 1 6V battery
• 3 pieces of wire (alligator clips will help out)
• 1 bulb with lamp
• Several plastic containers
• Copies of student worksheet, outlined below

• Distilled water
• Salt
• Vinegar
• Baking soda
• Anything else you want to try out (oil, sugar, orange juice…)

• Background information on batteries in the Sources of Electric Energy section of the Energy and the Environment background for Phase 1.
• Hixson, B.K. Edison Etc. Wild Goose Publications (1994).

Introduction:
Before starting this activity, students should be aware of the definition of electrolyte. As they complete they activity, students will have a hands-on experience to go with the definition.

Electrolyte - any substance that can become an ionic conductor of electricity when it is dissolved in a solvent, such as water.

Activity Procedure:
1. Students should carefully hook up two wires, one to each of the battery posts, making certain that the two terminals are not touching.

2. Take one of the wires attached to the battery posts and attach the free end to one end of the lamp and bulb set-up. Attach another (new) wire to the other end of the lamp set-up, leaving the other end of the wire unattached.

3. Touch the ends of the wire from the battery post and the other unattached wire from the lamp together to make certain that the light works.

4. Place both wires into one of the prepared solutions. If the bulb lights, you have an electrolyte.

5. Continue to test each of the other solutions. Record answers in a student worksheet, outlined below.

6. Questions to ask while interacting with students (or perhaps in a follow-up written assignment to reflect on what they have learned):

• Why does electricity flow through some solutions and not others?
• What happens if you mix an electrolyte with a non-electrolyte and attempt to run a current through it? Why do you think that happens?
• Can the electricity move in both directions in an electrolyte? How can you prove this?

Special Notes for Teachers to consider:

1. Safety
As students test different solutions, there is a tendency for them to get their hands wet as they dunk the wire. Make sure they clean their hands after each test. Some substances may irritate the eyes.

2. The Science Behind the Activity
An electrolyte is, by definition, any substance that can become an ionic conductor of electricity when it is dissolved in a solvent, such as water. The distilled water did not conduct electricity because there were no dissolved electrolytes in it. Once an electrolytic substance is dissolved in water, it facilitates the movement of the electrons as ions through the water from terminal to terminal so that there is a continuous current of electricity.

For further information, see the background on batteries in the Sources of Electric Energy section of the Energy and the Environment background for Phase 1.

3. Extension Idea
Students can measure the distance of the terminals and the intensity of the light given off. Students could measure intensity by the number of sheets of paper that light can pass through. As intensity decreases, fewer sheets of paper would allow light to pass through. It would be possible to graph this inverse relationship.

Student Worksheet: create a worksheet with the following headings, leaving space for students' responses.

Good Conductors

Poor Conductors

Include the following instructions: Make a list of things that were good conductors of electricity and things that were poor conductors during your testing procedure. Based on the results of your records below, can any inferences be made about the type of substances that form electrolytes when dissolved in water?

Back to: Light and Electricity Activities: Division II

Activity 3: Make your own voltaic pile

Integration Notes:
This activity, together with "Find Electrolytes," examines the electrochemical principles of batteries (electrolytes and electrodes). With this understanding in place, students will then be equipped to examine the environmental impact of batteries in Phase 2, which will lead to further environmental investigations relating to Nepal in later phases.

Learner Outcomes:
Students will:

• Construct their own voltaic pile which will deflect the needle of a multi meter or provide power for a simple LED or white LED (WLED).
• Describe the flow of electrical current within the circuit.
• Define the terms electrode, electrolyte, cell, voltage and battery.

Materials:
Per group

• 5 or more pennies (or pieces of copper sheeting)
• 5 or more small squares of aluminum foil or pieces of zinc metal
• Paper towel folded into squares (slightly larger than the pieces of metal)
• 1 to 2 cups of water
• Teaspoon of salt
• Multi meter or WLED
• Wire leads (copper works well)

Introduction:
Students will be creating a voltaic pile, which is a crude form of a battery.

Activity Instructions:
1. Dissolve the salt in the water.

2. Begin constructing the cell by layering the copper, the paper towel and the aluminum, in that order. The paper towel must separate the two metals so that they are not in contact. You will end up with the following order: copper, paper towel, aluminum, paper towel, copper, etc.

3. Continue layering the cells together until you have five pairs of metals in your voltaic pile.

4. Connect the wire leads from your multi meter to both ends of the pile and observe the deflection (movement) of the needle on the multi meter, indicating a current flowing through the wires.

5. Make your voltaic pile larger by adding more pairs of metals and check to see if there is any effect on the amount of current. If you have an LED connect it to your voltaic pile by touching the longer lead to the top layer of copper (or the penny) and touch the shorter lead to the bottom layer of aluminum.

6. Try constructing a voltaic pile by soaking the paper towel in vinegar rather than salt water and compare the amount of current to the current obtained by using salt water.

More Information (The Science Behind the Activity):
The voltaic pile that you constructed is a very simple battery, much like the ones used to provide electrical energy for watches, flashlights, clock radios and other small appliances. The voltaic pile is so named because a scientist named Alessandro Volta was the first person to create a simple battery.

The battery operates on the principle that if you separate two different metals (called electrodes) by a conducting liquid (called an electrolyte) that acts more strongly on one metal than on the other, electrons will move through the liquid, and the metal which is least acted upon will be charged to a higher electrical potential than the other. An electrical current can be made to flow from the metal with the high potential to the metal with the lower potential by completing an external circuit using a conductive wire.

The difference in electrical potential in the two metals is called voltage. By increasing the number of layers in your battery, you will increase the potential, and thus increase the voltage.

Special Considerations for Teachers:

Safety
This activity is not dangerous, but it is a good idea to have the students dismantle the voltaic piles once they are done, or else the metals will begin to corrode.

Extension Ideas