8 grade. 6 lab. Lesson
The title of the laboratory work: Study of a parallel connection of components in the electrical circuit
Purpose of the work:
- Make sure that the rules of parallel connection work.
Expected results:
- Electric current in different parts of the circuit is the different when the parts are connected in parallel. The current in all those parts sum up to the total current;
- The voltage of each part of the electric circuit that is connected in parallel is the same.
Teacher’s Guide:
- Divide the students to 3 students in each group.
- Before starting laboratory work, read the safety rules:
- To download the worksheet, please follow this link:
Theoretical part
Parallel connection is the one when all beginnings are bound in one bond and the ends are bound in another.
The rules of parallel connection:
Sources:
- Последовательное и параллельное соединение проводников. (2018). Физика. Учебник для 8 классаобщеобразовательной школы.
Experimental part
Experiment.
Procedure:
Step 1.
Assemble the circuit as shown in the photo. Turn on the switch. Take the measurements from the voltmeters U1and U2. Insert the results to the table.
Step 2.
Assemble the circuit as shown in the photo. Turn on the switch. Take the measurements from the ammeters I, I1, I2. Insert the results to the table.
Step 3. Make sure that the rule of parallel connection work.
Step 4. Taking into account the Ohm’s law, calculate the resistances R1 and R2 and their total resistance R:
Insert the results into the table. Compare the total resistance R and the sum of resistances R1+R2.
Step 5. Check that the following holds:
Considering the results, draw a conclusion.
Research part
| U1, V | U2, V | I, А | I1, А | I2, А | R1, Ohm | R2, Ohm | R, Ohm |
When deriving conclusions, answer the following questions:
- Which connection is called in parallel one?
- How electric current, voltage and resistance are identified in parallel connection?
Conclusion
Electric current in parallel connection is different in all parts of the circuit. These currents sum up to the total one. The voltage is the same in different parts of the circuit when connected in series.