LESSON PLAN



LESSON PLAN

Topic: Orange juice clock

Name: SAVITA PARMAR

Class: Physical science

Grade Level: 8 GATE

Major Concepts:

1. Two different metals are immersed in and electrolyte solution to produce

an electric current sufficient to run a clock.

2. Metals seem to compete for the electrons.

3. Metals like Li that are near the beginning of the activity series are

more likely to lose electrons that those of Au that are near the bottom.

4. The tendency of electrons to flow from the substance that is oxidized to

the substance that is reduced produces the voltage that we can harness in an

electrochemical cell.

Performance Objective / Content Standards: Chemistry

Atomic and Molecular Structure

1. The periodic table displays the elements in increasing atomic number and

shows how periodicity of the physical and chemical properties of the

elements relates to atomic structure. As a basis for understanding this

concept:

g. Students know how to relate the position of an element in the periodic

table to its quantum electron configuration and to its reactivity with other

elements in the table.

Materials and Equipment: large electric clock with a second hand that

operates with one AA cell, copper strip several cm. long, magnesium ribbon,

fine steel wool, orange juice, beaker to contain orange juice, 2 wires with

alligator clips about 30 cm long.

Independent practice / Assignments: The students shall observe a ready made

ìTwo Potato clockî or the ìlemon batteryî where the explanation and the

instructions would be provided by the teacher.

Outline of Lesson:

1. Use the steel wool to clean the copper strip and Mg ribbon.

2. Coil the Mg ribbon around a pencil.

3. Attach the 2 wires with alligator clip to the 2 contact points on the AA

cell holder in the back of the clock.

4. Fasten the Cu strip to the wire attached to + ve terminal of the holder

and Mg to the negative end.

5. Immerse the Mg and Cu electrodes in the orange juice.

6. Observe what happens to the second hand of the clock.

Explanation: Mg is more reactive than Cu and loses electrons more easily.

When the Mg reacts with the acid in the orange juice, it loses electrons.

The wires and the clock provide and external path for extra electrons to

move around to the copper and back to the juice forming a complete circuit.

Homework: Attempt the following activities and write the results in your

own words.

1. What will happen if the connections to the electrodes are reversed?

2. What other combinations of metals will work as an electrode?

3. What other substances will make a good electrolyte?

References: Mr. Al Guenther showed this demonstration during a workshop held

for Science teachers organized by Bureau of Education and Research at

Anaheim, California.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download