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How Magnets Were Discovered
Everyday Examples of Magnets
- Magnets can be fun to play with.
- Examples of magnets in daily life:
- Stickers on iron surfaces (e.g., refrigerators)
- Pin holders where pins stick to the holder
- Pencil boxes with tight-fitting lids
How Magnets Were Discovered
- Story of Shepherd Magnes:
- Lived in ancient Greece.
- Discovered his iron-tipped stick was stuck to a rock.
- The rock was a natural magnet (magnetite).
- Magnetite:
- Named possibly after Magnes or the place Magnesia.
- Attracts iron.
- Early discovery led to naming these substances magnets.
Types of Magnets
- Natural Magnets: Found in nature, like magnetite.
- Artificial Magnets: Made from pieces of iron.
- Different shapes: bar magnets, horseshoe magnets, cylindrical magnets, ball-ended magnets.
Activity: Floating Clip (click here)
- Materials Needed:
- Plastic or paper cup
- Stand and clamp
- Magnet
- Paper cover
- Thread
- Iron clip
- Steps:
- Fix the cup on the stand using a clamp.
- Place the magnet inside the cup and cover it with paper.
- Attach a thread to an iron clip and fix the other end to the stand’s base.
- Bring the clip near the cup’s base.
- Watch the clip float in the air like a kite!
Magnetic and Non-Magnetic Materials
Activity 2: Magnet Walk
- Create a Magnet Stick:
- Attach a small magnet to a stick (hockey stick, walking stick, cricket wicket) with tape or glue.
- Explore the Playground and Classroom:
- Use the Magnes stick to pick up various objects.
- Test different objects to see if they stick to the magnet.
- Record Observations:
- Make a table to note which objects are attracted to the magnet.
- Identify the materials of the attracted objects.
- Common materials attracted to magnets are iron, nickel, and cobalt.
- Objects not attracted to magnets are non-magnetic (e.g., plastic, wood).
Activity 3: Magnet in Soil
- Test Soil for Iron:
- Rub a magnet in sand or soil.
- Check for particles sticking to the magnet.
- Shake the magnet gently to remove non-metallic particles.
- Remaining particles may be iron filings.
- Try at Different Loc
- Conduct the activity at various places (home, school, holiday spots).
- Compare the amount of iron filings found.
Poles of a Magnet
Activity 4: Iron Filings and Magnet
- Observe Iron Filings:
- Spread iron filings on paper.
- Place a bar magnet on the filings.
- Notice where the filings stick to the magnet.
- Patterns of Attraction:
- Iron filings stick more at the ends of the magnet.
- These ends are the poles of the magnet.
- Experiment with Different Shapes:
- Use magnets of various shapes.
- Observe and mark the poles.
Key Points
- Magnetic Materials:
- Attracted to magnets.
- Examples: iron, nickel, cobalt.
- Non-Magnetic Materials:
- Not attracted to magnets.
- Examples: plastic, wood.
- Poles of a Magnet:
- Located at the ends of the magnet.
- Strongest attraction points for iron filings.
Finding Directions
Ancient Use of Magnets
- Story of Emperor Hoang Ti:
- Emperor had a chariot with a statue of a lady.
- Statue’s arm always pointed South, helping the emperor find directions.
Activity 5: Making a Direction Finder
- Materials Needed:
- Bar magnet
- Thread
- Wooden stand
- Steps:
- Mark one end of the bar magnet.
- Tie the magnet in the middle with the thread and suspend it from the stand.
- Let the magnet come to rest and mark the positions of its ends.
- Draw a line between the two points to show the magnet’s resting direction.
- Rotate the magnet and let it come to rest again, noting its direction.
- Repeat several times to see if it always points in the same direction.
- Observations:
- The freely suspended magnet always points in the North-South direction.
- The end pointing North is the North pole, and the end pointing South is the South pole.
- Experiment with Other Objects:
- Try with an iron bar and a plastic or wooden scale.
- These do not point in a consistent direction like the magnet.
Understanding Magnet Poles
- Poles of a Magnet:
- North seeking end = North pole.
- South seeking end = South pole.
- All magnets, regardless of shape, have two poles (North and South).
Using the Sun for Directions
- Finding Directions with the Sun:
- The Sun rises in the east.
- Stand facing east; North will be on your left.
- Use this to determine which end of the magnet points North.
Compass: The Direction Finder
- Description:
- A compass is a small box with a glass cover and a magnetized needle.
- The needle rotates freely and aligns with the North-South direction.
- The compass dial is marked with directions.
- How to Use a Compass:
- Place the compass where you need to find directions.
- The needle points North-South.
- Rotate the compass until the dial’s North and South match the needle ends.
- The North end of the needle is usually painted a different color.
Importance of Magnet Direction Property
- Historical Use:
- Ancient travelers used suspended natural magnets to find directions.
- Modern Use:
- Compasses help in navigation by indicating the North-South direction.
Make Your Own Magnet
Creating a Magnet
- Materials Needed:
- Rectangular piece of iron
- Bar magnet
- Steps:
- Place the iron piece on a table.
- Move one pole of the bar magnet along the length of the iron piece without lifting it.
- Repeat 30-40 times, always moving in the same direction.
- Test with a pin or iron filings to see if it has become a magnet.
- If not magnetized, repeat the process longer.
- Other Items to Magnetize:
- Iron nail, needle, or blade.
Activity 6: Making a Compass
- Materials Needed:
- Magnetized iron needle
- Small piece of cork or foam
- Bowl or tub of water
- Steps:
- Insert the magnetized needle through the cork.
- Float the cork in water without letting the needle touch the water.
- Observe the direction the needle points.
- Rotate the cork and observe if the needle points in the same direction again.
Attraction and Repulsion Between Magnets
Activity with Toy Cars
- Materials Needed:
- Two small toy cars
- Two bar magnets
- Rubber bands
- Steps:
- Fix a bar magnet on each car with rubber bands.
- Label cars as A and B.
- In car A, place the south pole at the front.
- In car B, place the north pole at the front.
- Place the cars close and observe if they attract or repel.
- Try different positions and observe the movements.
- Observations:
- Similar poles repel each other.
- Opposite poles attract each other.
Magnet Properties and Care
Important Points
- Magnet Care:
- Magnets lose properties if heated, hammered, or dropped.
- Store bar magnets in pairs with unlike poles on the same side.
- Use pieces of wood and soft iron for safe storage.
- Keep horse-shoe magnets with a piece of iron across the poles.
- Keep Away from Electronics:
- Magnets should be kept away from cassettes, mobiles, televisions, music systems, CDs, and computers.
Chapter Summary:
- Magnetite is a natural magnet.
- Magnet attracts materials like iron, nickel, and cobalt. These are called magnetic materials.
- Materials that are not attracted to magnets are called non-magnetic.
- Each magnet has two magnetic poles—North and South.
- A freely suspended magnet always aligns in the North-South direction.
- Opposite poles of two magnets attract each other, whereas similar poles repel one another.
Keywords
- Compass
- Magnet
- Magnetite
- North pole
- South pole
