Topicm4ff2fbaeaed6fb32_1528449000663_0Topic

Study of the relationship between the current and the electrical voltage in the circuit

Levelm4ff2fbaeaed6fb32_1528449084556_0Level

Second

Core curriculumm4ff2fbaeaed6fb32_1528449076687_0Core curriculum

VI. Electricity. The student:

12) uses the concept of electrical resistance as the property of a conductor; applies to calculations the relationship between voltage, current and resistance; uses a resistance unit;

16) experimentally: 
e) determines the resistance of the conductor by measuring the voltage at its ends and the current flowing through it.

Timingm4ff2fbaeaed6fb32_1528449068082_0Timing

45 minutes

General learning objectivesm4ff2fbaeaed6fb32_1528449523725_0General learning objectives

Experimental examination of the relationship between the voltage and the intensity of electric current.

Key competencesm4ff2fbaeaed6fb32_1528449552113_0Key competences

1. Building of a simple electrical circuit.

2. Measurement of the voltage and the current intensity.

3. Formulating a research hypothesis related to the voltage and the current intensity.

Operational (detailed) goalsm4ff2fbaeaed6fb32_1528450430307_0Operational (detailed) goals

The student:

- builds simple circuits using an ammeter and a voltmeter,

- determines the relationship between the voltage and  the current.

Methodsm4ff2fbaeaed6fb32_1528449534267_0Methods

1. Discussion developing in the course of common problem solving by a class or group.

2. Organizing and applying the obtained results in new tasks of a practical or theoretical nature.

Forms of workm4ff2fbaeaed6fb32_1528449514617_0Forms of work

1. Experimenting in groups.

2. Brainstorm.

Lesson stages

Introductionm4ff2fbaeaed6fb32_1528450127855_0Introduction

Prepare answers to introductory questions for the lesson.

1. What is electric current?
2. What physical quantity best describes the amount of current flowing?
3. Define a 1 A unit.
4. What is electric voltage?
5. Define a 1 V unit.
6. To measure what quantity we use ammeterammeterammeter and voltmetervoltmetervoltmeter?

Procedurem4ff2fbaeaed6fb32_1528446435040_0Procedure

Nowadays it is hard to imagine life without electricity. 
We use various elements through which electric current flows. 
Some elements of the devices are very large, which is why we often use schematic symbols.

Thanks to this, even a complicated circuit can be presented on a small sheet.

The ability to draw diagrams is important when studying the relationship between the quantities describing the electrical circuit.

What are the schematic designations of various elements of electrical circuits?

[Illustration 1]

[Slideshow]

How to connect an ammeterammeterammeter correctly?

The ammeter must measure the amount of charge that flows through the electrical receiver for one second. It should therefore always be connected in series to the resistor.m4ff2fbaeaed6fb32_1527752263647_0The ammeter must measure the amount of charge that flows through the electrical receiver for one second. It should therefore always be connected in series to the resistor.

[Illustration 2]

How to connect a voltmetervoltmetervoltmeter correctly?

The voltmeter measures the voltage between two points. The voltmeter's probes must be in contact with these points.

[Illustration 3]

[Illustration 4]

Experiment:

Study of the relationship between the voltage and the current flowing through the conductor.m4ff2fbaeaed6fb32_1527752256679_0Study of the relationship between the voltage and the current flowing through the conductor.

Research hypothesis:

There is a relationship between the voltage applied to the electric current receiver and the current flowing through the conductor:

1. Build an electrical circuit as shown in the diagram below.

[Illustration 5]

2. On the power supply, change the supply voltage and read it on a voltmeter.

3. With a given voltage, read out what current flows through the resistorresistorresistor.

4. Record results in the measurement table.

[Table 1]

Elaboration of measurements:

5. Draw a graph of current dependence on the supply voltage.

6. For each measurement, determine the ratio $\frac{U}{I}$ and write it in the table.

7. Compare the results of the $\frac{U}{I}$ and confirm or disprove the research hypothesis.

Lesson summarym4ff2fbaeaed6fb32_1528450119332_0Lesson summary

1. Electrical circuits are systems of elements (wires, voltage sources, receivers, switches) connected in such a way as to allow the flow of electric current.

2. AmmeterammeterAmmeter is a device used for measuring the intensity of electric current; it is connected in series to the circuit.

3. The voltmetervoltmetervoltmeter is a device used to measure the voltage; it is connected in parallel to the circuit.

4. The current can only flow in closed electrical circuits.

5. The electrical circuit diagram is a sketch made with the use of graphic symbols, allowing to represent all elements of the electric circuit and their connections.

6. The intensity of electric current flowing through the receiver is directly proportional to the electrical voltage measured between its ends.

Selected words and expressions used in the lesson plan

resistorresistorresistor

switchswitchswitch

voltmetervoltmetervoltmeter

ammeterammeterammeter

voltage sourcevoltage sourcevoltage source