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What is Paramagnetic Material?
Grade Level:
Class 7
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
Paramagnetic materials are substances that are weakly attracted to a magnet. Unlike permanent magnets, they don't stay magnetic on their own and lose their magnetism once the external magnet is removed.
Simple Example
Quick Example
Imagine you have a small iron pin and a strong fridge magnet. The iron pin sticks to the magnet, right? Now, if you try to stick a small piece of aluminium foil to the same magnet, it might feel a very, very slight pull, but it won't stick properly. Aluminium is a paramagnetic material – it's weakly attracted, but not enough to stick like iron.
Worked Example
Step-by-Step
Let's say we have a powerful magnet and three different materials: a steel spoon, a piece of wood, and a small packet of oxygen gas (liquid oxygen at very low temperatures behaves paramagnetically).
Step 1: Bring the magnet near the steel spoon. --- Observation: The steel spoon is strongly attracted and sticks to the magnet. This shows strong magnetic properties (ferromagnetic).
Step 2: Bring the magnet near the piece of wood. --- Observation: There is no attraction at all. Wood is a non-magnetic material.
Step 3: If we could, bring the magnet near the packet of liquid oxygen. --- Observation: You would notice a very slight, almost unnoticeable, attraction. The oxygen would be very, very gently pulled towards the magnet, but not stick.
Answer: The oxygen is showing paramagnetic behaviour because it's weakly attracted to the magnet, unlike the strongly attracted steel or the completely unaffected wood.
Why It Matters
Understanding paramagnetic materials is crucial in developing advanced technologies. They are used in medical imaging like MRI machines (HealthTech) to help doctors see inside our bodies, in some types of sensors for Robotics, and even in Chemistry labs to study different substances. This knowledge can lead to careers in medical technology, materials science, or research.
Common Mistakes
MISTAKE: Thinking paramagnetic materials are strongly attracted to magnets. | CORRECTION: Paramagnetic materials are only WEAKLY attracted to magnets. The attraction is very subtle.
MISTAKE: Confusing paramagnetic materials with permanent magnets. | CORRECTION: Paramagnetic materials only show magnetism when an external magnet is present. They don't remain magnetic on their own.
MISTAKE: Believing all metals are strongly magnetic. | CORRECTION: While some metals like iron are strongly magnetic (ferromagnetic), many metals like aluminium and platinum are only weakly paramagnetic.
Practice Questions
Try It Yourself
QUESTION: Is a substance that is slightly pulled towards a magnet but doesn't stick considered paramagnetic? | ANSWER: Yes, that describes a paramagnetic material.
QUESTION: If you place a strong magnet near a substance and it shows a very faint attraction, but loses this attraction immediately when the magnet is removed, what type of material is it likely to be? | ANSWER: It is likely a paramagnetic material.
QUESTION: Imagine you have three unknown samples. Sample A sticks strongly to a magnet. Sample B shows no reaction. Sample C is very, very slightly pulled towards the magnet but doesn't stick. Identify which sample is paramagnetic. | ANSWER: Sample C is paramagnetic.
MCQ
Quick Quiz
Which of these is a characteristic of paramagnetic materials?
They are strongly attracted to magnets.
They repel magnets.
They are weakly attracted to magnets.
They become permanent magnets.
The Correct Answer Is:
C
Paramagnetic materials are defined by their weak attraction to an external magnetic field. They do not repel magnets, are not strongly attracted, and do not become permanent magnets.
Real World Connection
In the Real World
In India, paramagnetic properties are important in advanced medical diagnostic tools. For instance, MRI machines used in hospitals across cities like Delhi, Mumbai, or Bengaluru, rely on understanding how certain atoms (like hydrogen in water) behave paramagnetically in a strong magnetic field to create detailed images of our internal organs and tissues. This helps doctors diagnose diseases without surgery.
Key Vocabulary
Key Terms
MAGNETISM: The force exerted by magnets, attracting or repelling certain materials. | ATTRACTION: The force that pulls two objects towards each other. | EXTERNAL MAGNET: A magnet that is brought near another substance to test its magnetic properties. | FERROMAGNETIC: Materials like iron and steel that are strongly attracted to magnets and can become permanent magnets.
What's Next
What to Learn Next
Next, you can learn about 'Diamagnetic Materials'. This will help you understand another type of magnetic behaviour where materials are actually repelled by magnets, completing your basic knowledge of how different substances interact with magnetic fields.
