A magnet is an object that produces a magnetic field and can attract magnetic materials such as iron, nickel and cobalt. Two common types are the bar magnet — a rectangular solid with distinct north and south poles — and the horseshoe magnet — U-shaped to bring poles closer together for a stronger field at the ends. Both show the basic property of poles: like poles repel and unlike poles attract.

Magnetic poles are the ends of a magnet where magnetic forces are strongest, called North and South poles. The rule is: like poles (N—N or S—S) repel, while unlike poles (N—S) attract. For example, two bar magnets with opposite poles facing each other will stick together (attract), while two north poles brought together will push each other away (repel).

A magnetic field is the region around a magnet where its magnetic force acts. Magnetic field lines are imaginary lines used to represent this field; they are drawn from the North pole to the South pole outside the magnet and from South to North inside, forming closed loops. The density of these lines indicates the field strength — closer lines mean stronger field.

Place a bar magnet on a flat tray and cover it with a sheet of paper. Sprinkle iron filings evenly on the paper and tap gently. The filings arrange themselves along curved lines from the magnet's north pole to its south pole, revealing the magnetic field pattern. This shows that the field is strongest near the poles (where filings are denser) and that field lines do not cross.

When a magnet is cut into two pieces, each piece becomes a smaller magnet with its own North and South poles. This demonstrates that poles always occur in pairs and that isolated single poles (monopoles) are not produced by simple cutting — the magnetic domains inside rearrange so each fragment forms a complete dipole.

Magnetic materials (e.g., iron, nickel, cobalt) are attracted to magnets because their atomic magnetic moments can align with an external field, producing net magnetism. Non-magnetic materials (e.g., wood, plastic, glass) lack this internal alignment and therefore do not respond to magnetic fields. The difference is due to the electronic structure and domain alignment within the materials.

When an iron nail is placed near a strong magnet, the magnetic field causes the magnetic domains within the nail to align in a common direction, making the nail behave like a magnet temporarily. Once the external magnet is removed, thermal motion and randomizing influences cause the domains to lose alignment, and the nail gradually loses its induced magnetism, returning to a non-magnetised state.

Not all coins are magnetic; it depends on the metal used. Coins containing iron or steel will show magnetic attraction, while those made of copper, aluminium or other non-magnetic alloys will not. To test, bring a magnet close to the coin and observe if it is attracted. Record observations and explain based on coin composition.

Copper and aluminium have electronic structures and atomic arrangements that do not allow permanent magnetic domain formation; their magnetic moments cancel out in the material, so they are not attracted to permanent magnets. Conductivity relates to electron mobility for electric current, which is a different property from magnetism.

Steel, an alloy primarily of iron, is usually magnetic because it contains iron atoms whose domains can be aligned. Certain types of steel (e.g., hardened steel with appropriate treatment) retain domain alignment well, making them suitable as permanent magnets. Steel's mechanical strength and ability to hold magnetization make it useful for many magnetic applications.

Permanent magnets retain magnetism for a long time (e.g., fridge magnet, magnetized sewing needle) because their domains remain aligned. Temporary magnets behave like magnets only in the presence of an external magnetic field and lose magnetism when the field is removed (e.g., a paper clip or soft iron nail near a magnet). Permanent magnets are made of materials and treated to lock domain orientation; temporary magnets are easily magnetized and demagnetized.

Heating increases atomic motion, disturbing domain alignment and causing loss of magnetism. Hammering or striking a magnet physically disturbs domains and can randomize their orientation. Subjecting a magnet to a strong alternating or reverse magnetic field flips domains or reduces net alignment. Each method disrupts the ordered domain structure responsible for magnetism.

A keeper is a soft iron bar placed across the poles of a horseshoe or bar magnet when stored. It provides a path of low reluctance for magnetic flux, reducing stray fields and preventing domain movement that would weaken the magnet. Keepers help maintain magnetization by closing the magnetic circuit and protecting poles from external demagnetizing influences.

Keep magnets away from electronic devices, credit cards, and magnetic storage media. Avoid letting small strong magnets come into contact with children or be swallowed. Handle heavy or strong magnets with care — they can snap together and pinch skin. Store with keepers or spacers to prevent damage and reduce demagnetization.

Temperature influences domain alignment; heating supplies energy that randomizes magnetic domains, weakening or removing magnetism. For example, heating a magnet near or above its Curie temperature causes it to lose permanent magnetism. Conversely, cooling can help maintain domain alignment and magnet strength.

Materials: bar magnet, unknown metal object, thread, stand (optional). Steps: Bring the magnet close to the object and observe attraction. Alternatively, suspend the object by a thread and bring a magnet near to see movement. Expected conclusion: If the object is attracted, it contains magnetic material like iron; if not, it is non-magnetic. Record observations and possible sources of error (coating on object, weak magnet).

Magnetize a small needle by stroking it with a bar magnet several times in one direction. Float the needle on a small piece of cork in water or balance it on a pin. The magnetized needle aligns itself with Earth's magnetic field, pointing approximately north-south. The end pointing north is called the north-seeking pole of the needle and helps in navigation.

Take two identical bar magnets and hold them with different orientations: N to S (opposite) and N to N or S to S (like poles). When N faces S, students should observe attraction and magnets sticking together; when like poles face, they should feel a push or see the magnets repel and not come together. This shows pole interactions clearly.

Place filings over a paper on top of a magnet; observe density of filings. Areas where filings cluster densely (near poles) indicate stronger fields, while sparse regions indicate weaker fields. By comparing different locations around different magnets or different parts of the same magnet, students can visualise relative field strength.

Record object name, material (if known), whether attracted (yes/no), distance at which attraction starts, and any anomalies (e.g., coated objects). Present conclusions summarising which materials are magnetic and possible reasons. Discuss experimental errors like weak magnets, coatings or measurement inaccuracies.

A compass contains a freely rotating magnetized needle that aligns with Earth's magnetic field. The needle's north-seeking pole points roughly towards Earth's geographic north because Earth's magnetic field lines run from the magnetic south to magnetic north in the region; thus the compass provides a reliable reference for direction. Navigation uses this constant orientation to determine bearings and routes.

Electric motors convert electrical energy into mechanical motion. In simple motors, magnets and current-carrying coils interact: when a current flows through a coil placed in a magnetic field, forces act on the coil making it turn. Reversing the current or using a commutator keeps the motion continuous, driving devices like fans and toys.

Speakers have a magnet and a coil attached to a cone. Electrical signals (audio) are sent through the coil, causing it to move in the magnetic field. This movement pushes and pulls the cone, making vibrations in the air that we hear as sound. The magnet is essential to convert electrical energy into mechanical vibration.

MRI (Magnetic Resonance Imaging) in medicine uses very strong magnets to align tiny particles in the body; signals from these alignments are detected and used to form images of internal structures. Industrially, magnetic separators remove ferrous metals from mixtures by attracting magnetic particles, proving useful in recycling and safety processes. Both rely on the attraction between magnets and magnetic materials.

Fridge magnets hold notes on the refrigerator; magnetic latches keep cabinet doors closed; and magnetic sensors are used in some switches and toys. In each case, magnetic attraction or magnetic switching is used for holding, sensing or creating motion in simple, reliable ways.

Field lines represent the direction of the magnetic force at each point in space. If two lines crossed, it would imply two different directions of force at the same point, which is impossible. Therefore field lines must be continuous and never intersect, ensuring a unique direction everywhere in the field.

Magnetism depends on electromagnetic forces, which operate everywhere in the universe, including outer space. Earth's magnetic field extends into space and affects charged particles (e.g., in the magnetosphere). Therefore magnetic effects occur in space, though specific interactions depend on presence of magnetic materials, fields and charged particles.

Use a strong magnet over the mixture; iron filings will cling to the magnet, leaving sand behind. Repeat if needed for thorough separation. Limitations include: very fine filings mixing with sand might be hard to remove completely and coatings on metal particles can reduce attraction.

A strong nearby magnet produces a local magnetic field stronger than Earth's field in the vicinity, causing the compass needle to align with the nearby magnet instead. Navigators should keep compasses away from large magnetic objects and electronic devices; they should also calibrate or check bearings against known landmarks when possible.

Key points: definition and types of magnets; poles and the rule of attraction/repulsion; magnetic field and field lines; magnetic vs non-magnetic materials; temporary and permanent magnets; simple experiments (iron filings, attraction test, compass making); applications like motors, speakers and separators; and basic safety and care of magnets. Practice diagrams and experiment steps to score well in exams.