Olympiad Notes: Fun with Magnets | Science Olympiad Class 6 PDF Download

Magnets

Definition

• A magnet refers to a material or object possessing the ability to attract or exert a pulling force on ferromagnetic substances such as iron, cobalt, nickel, etc.
• Attraction to Ferromagnetic Materials: Magnets exhibit an attraction towards ferromagnetic materials, drawing substances like iron toward themselves.
• Interaction with Other Magnets: Magnets also demonstrate the ability to both attract and repel other magnets.

Everyday Applications:

• Refrigerator Doors: Magnets are commonly used in refrigerator doors to keep them closed.
• Magnetic Closure Buttons: Pencil boxes or purses often utilize magnetic closure buttons for convenience.
• Waste Iron Separator: In waste management, magnets are employed to separate iron from other materials.

Magnets Discovery Types and Poles

Discovery

• Magnets are attributed to Magnes, an ancient Greek shepherd, who observed an iron-end stick being attracted to a rock on a hill.

Magnetite

• This rock was composed of Magnetite, a mineral containing iron, which possessed magnetic properties.

Types of Magnets

• Natural Magnets: Found in nature, natural magnets are composed of magnetite.
• Artificial Magnets: Created through various processes, artificial magnets are made using iron. Examples include bar, horseshoe, cylindrical, and ball-end magnets.

Magnet's Structure

• Most Magnetism at Ends: Magnets exhibit the highest magnetism at their two ends, referred to as poles.
• North and South Poles: Conventionally, these ends are labeled as North (N) and South (S). In a freely suspended magnet:
  • North-Seeking End: The end pointing towards the geographical North is termed the North-seeking end or North Pole.
  • South-Seeking End: The opposite end, pointing towards the geographical South, is called the South-seeking end or South Pole.

Magnetic and Non Magnetic Materials

• Magnetic Materials: These are substances that exhibit attraction towards magnets. Examples include iron, nickel, and cobalt.
• Non-Magnetic Materials: These substances do not demonstrate attraction to magnets. Examples comprise materials such as paper, wood, and plastic.

Finding directions using Magnet

• Alignment Property of Freely Suspended Magnet: When freely suspended, a magnet consistently aligns itself in the North-South direction, a characteristic historically utilized for navigation purposes.
• Compass: A device designed for direction-finding purposes.
• Components of a Compass:
  • Magnetized Needle: The compass comprises a magnetized needle enclosed in a box with a glass cover.
  • Dial with Directions: Inside the box, there's a dial marked with cardinal directions.
• Functionality: The needle, capable of free rotation, settles in the North-South orientation as indicated on the dial. To distinguish between the two ends, the north pole of the needle is typically marked in red, contrasting it from the south pole.

Making own Magnet

• Materials Required: An iron bar and a magnet bar.
• Procedure:
  • Positioning the Magnet: Place one pole of the magnet at the edge of the iron bar.
  • Sliding Movement: Without lifting the magnet, slide it along the length of the iron bar towards the opposite edge.
  • Lifting and Repositioning: Lift the magnet and return it to the initial position, ensuring the same pole touches the iron bar.
  • Repetition: Repeat this process continuously for around 30 to 40 times or more.
• Objective: The aim is to magnetize the iron bar through repeated contact with the magnet.

Making own Compass

• Materials Needed: A cork, a magnetized needle (prepared using the previous process), and a bowl of water.
• Assembly:
  • Affixing the Needle: Glue the magnetized needle onto the cork in a way that the needle does not touch the water when placed in the bowl.
  • Placement: Set the cork with the needle in the bowl of water.
• Observation:
  • Rotational Movement: Even after rotating the cork several times in any direction within the water, the needle on the cork will cause the cork to reorient itself so that the needle points in the North-South direction.
• Result: The magnetic properties of the needle align the cork in accordance with the Earth's magnetic field, consistently pointing the needle towards the North-South direction.

Attraction and Repulsion

Magnet's Interaction with Iron

• Attraction to Iron: Magnets exhibit an attraction towards iron.

Interaction between Magnets

• Similar Poles: When the like or same poles of two magnets are brought closer, they repel each other. For instance, the south pole of one magnet repels the south pole of the other, and similarly, the north pole of one magnet repels the north pole of another.
• Opposite Poles: Conversely, when unlike or different poles of two magnets are brought closer, they attract each other. For example, the south pole of one magnet attracts the north pole of the other, and vice versa.

Precautions with Magnets

Conditions Damaging Magnets

• Loss of Magnetism: Magnets can lose their magnetic properties when subjected to heat, hammering, or dropped from a height.
• Weakening due to Improper Storage: Improper storage can lead to a weakening of magnetism over time.

Proper Storage Guidelines for Magnets

• Storage Arrangement: Keep magnets in pairs with unlike poles facing each other. Separate them with a piece of wood, and place two pieces of soft iron across their ends.
• Horse-shoe Magnet: For a horse-shoe magnet, position a piece of iron across its poles to maintain magnet strength.

Adverse Effects and Precautions

• Equipment Caution: Keep magnets away from cassettes, mobile devices, televisions, music systems, CDs, and computers to prevent adverse effects on the equipment.