STAO On Line workshops

Contents

Home

Overview

Organizing Your Lab

Lesson 1
A Simple Electric Circuit

Lesson 2
A Series Circuit

Lesson 3
A Parallel Circuit

Lesson 4
Cells & Batteries Sources in Series and Parallel

Lesson 5
Resistance - Ohm’s Law

Lesson 6
Canadian Electricity Alternatives

Course Facilitator & FAQ's

Expectations

Acknowledgements

Lesson 4: Cells & Batteries Sources in Series and Parallel

Downloadable student notes (.doc .wdp .pdf )

Downloadable answers to student notes (.doc .wpd .pdf )

Sources In Series

Wooden Block Model

By now the students may not need to actually participate in this model. Simple descriptions may be enough.

Sources Connected in Series

Set up a simple circuit of student; battery, switch, conductors and bulb. Turn the circuit on and have the ammeter measure the current.

Now add another battery in series. The first battery lifts the blocks from ankle to waist level (one volt). The second battery lifts the blocks from waist to shoulder height (another volt). We now have a 2 Volt Battery. The conductors at that positive side of the battery must conduct the blocks along at ankle level. (They can sit on the floor).

Remind the students one coulomb falling through a distance of 1 volt has enough energy to get the student once around. One coulomb falling through 2 volts will make the student load turn around twice (or faster).

Since the coulomb causes the student bulb to turn faster, the current through the bulb increases.

Sources Connected in Parallel

Set up a simple circuit of student; battery, switch, conductors and bulb. Turn the circuit on and have the ammeter measure the current.

Now add another battery in parallel. Both batteries lift the blocks from waist to shoulder height (one volt).

Remind the students one coulomb falling through a distance of 1 volt has enough energy to get the student once around. It therefore still takes 1 coulomb to make the student load get once around.

Since all coulombs have the same energy it, the student bulb spins at the same speed. Therefore the current through the bulb stays the same.

Questions

"Disconnect" one branch of the circuit. Does the current change through the one bulb?

Do the two negative & positive boxes have any effect on how fast energy is released from the one bulb?

Do they affect how long the bulb will give off light?

Do they affect how much light the bulb will give off before the battery goes dead?

Why do tiny batteries "go dead" quickly, while large ones seem to last longer?

Demonstration [CARE] View How To Remove A Battery's Cover video

Get several old 9 volt batteries and 6 volt lantern batteries. Carefully remove the metal covering with pliers. The metal edges can be sharp so wear gloves. Wrap the 9 volt "transistor" battery with clear packing tape to keep any electrolyte from contacting the students. This is a nice demonstration of cells connected in series to increase voltage.

The 6 volt lantern battery often has a series / parallel connection as shown in the student notes.

You can also obtain 12 and 6 volt lead acid car and motorcycle batteries as examples of series connection of cells that produce more than 1.5 volts. These are heavy though and you must be careful of the sulphuric acid electrolyte. Have the students count the number of cells then figure out the voltage of each cell (2 volts).

Many toys and flashlights can be used to demonstrate how cells are connected to either increase voltage or cell life. Have the students figure out how the cells are connected by first visually tracing the connections then measuring the total voltage.