Teachers TryScience

Conductivity of Liquids

Dec 21 2015

Source: TTS Haryana Sci...

Summary Information

Keywords:

Electricity, insulators, conductors , liquid, ions

Topic:

Chemistry

Workplace Skills:

Secondary Research

Use of Data

Discussion

Target Grade (Ages):

Grade 6 (Ages 11-12)

Grade 7 (Ages 12-13)

Grade 8 (Ages 13-14)

Diversity Indicators:

This lesson is suitable for rural Indian government school students.

Tab Wrapper

LESSON

Goals and Prerequisites

Goals:

To know the conductivity of electricity in different liquids.

Prerequisites:

Students should be able to build a simple electric circuit.

Instructional Objective(s)

At the end of the lesson plan students will -

Test the conductivity of a variety of liquids.
Classify common household liquids as conductors or
nonconductors.

Instructional Resources

Background:

The materials that conduct electricity are conductors and those that do not conduct are insulators. When electricity is passed through a conducting solution, the molecules of the solution dissociate into ions, which cause electrical conduction through liquids. This process is due to the chemical effect of electric current.

Materials:

Bottle caps
2 dry cells
Cell holder
Torch or LED
Bulb
Switch
lemon juice
Vinegar
Tap water
Distill water
Wires
Crocodile clips

Procedure:

Collect a few small plastic or rubber caps of discarded bottles and clean them.
Pour one teaspoon of lemon juice or vinegar in one cap. Bring your tester over this cap and let the ends of the tester dip into lemon juice or vinegar .
Take care that the ends are not more than 1 cm apart but at the same time do not touch each other. Does the bulbof the tester glow? Does lemon juice or vinegar conduct electricity?
How would you classify lemon juice or vinegar— a good conductor or a poor conductor?
Take about two teaspoonfuls of distilled water in a clean and dry plastic or rubber cap of a bottle. (You may obtain distilled water from your school science lab. You may also get distilled water from a medical store or a doctor or a nurse).
Use the tester to test whether distilled water conducts electricity or not. What do you find? Does distilled water conduct electricity?
Now dissolve a pinch of common salt in distilled water. Again test. What do you conclude this time?
When salt is dissolved in distilled water, we obtain salt solution. This is a conductor of electricity.
The water that we get from sources such as taps, hand pumps, wells and ponds is not pure. It may contain several salts dissolved in it. Small amounts of mineral salts are naturally present in it. This water is thus a good conductor of electricity. On the other hand, distilled water is free of salts and is a poor conductor.

Conclusion -

When the liquid between the two ends of the tester allows the electric current to pass, the circuit of the tester becomes complete. The current flows in the circuit and the bulb glows. When the liquid does not allow the electric current to pass, the circuit of the tester is not complete and the bulb does not glow.

Assessments and Rubrics

Ask students to define and give examples of conductors and

nonconductors.

RESOURCES

Original Resources

Click the button above to add resource materials for this lesson.

Contributed Resources

Contribute a Resource

Click the button above if you would like to contribute a resource to this lesson.

STANDARDS/CURRICULUM

Add Standards/Curriculum

Select any filter and click on Apply to see results

Your Rating:

No votes yet

Search form

Languages