8 grade. 9 lab. Lesson
The title of the laboratory work: Assembling an electromagnet and checking its operation
Purpose of the work:
• Check experimentally the dependence of the action of an electromagnet on the current strength in the electromagnet winding and the presence of a core;
• Compare the magnetic fields created by a bar magnet and the current in a solenoid.
Expected results:
• The magnetic field of the coil can be strengthened using a core.
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
An electromagnet is a coil with an iron core inside. The core is an iron rod placed inside the coil. A coil with a core is called an electromagnet.
Sources:
- Электромагниты и их применение. (2018). Физика. Учебник для 8 класса общеобразовательной школы.
Experimental part
Experiment 1. Study of the dependence of the magnetic properties of a coil with current on the core.
Procedure:
Step 1.
Assemble a series circuit from a current source, a switch, a coil and a rheostat. Lock the key.
Step 2.
Identify the poles of the coil using a magnetic needle.
Step 3.
Remove the magnetic needle along the axis of the coil to such a distance at which the needle begins to orient itself along the magnetic lines of the Earth. The effect of the coil’s magnetic field on the needle is negligible. Insert the core into the coil. Observe the action of the core coil on the magnetic needle. Draw a conclusion.
Experiment 2. Comparison of the magnetic field lines of a coil with the field of a strip magnet.
Procedure:
Step 1.
Place magnetic arrows around the core coil.
Step 2. Draw the magnetic field lines of the coil. Compare the fields of a horseshoe magnet and a cored coil. Draw a conclusion.
Research part
When deriving conclusions, answer the following questions:
- What do the magnetic field lines of a current-carrying coil look like? How is their direction determined?
- In what ways can the magnetic field of a current-carrying coil be enhanced?
- What is an electromagnet?
Conclusion
The magnetic field of the coil can be strengthened using a core.