- Magnetic materials have magnetic domains. These are clusters of atoms that act like tiny magnets. When they are pointing in the same direction, magnetic lines of force can form. In this experiment, we will make a temporary magnet and observe the affect on a compass.
MATERIALS NEEDED:
Iron Fillings
Compass
Bar magnet (at least as long as the straw being used)
Drinking straw (may be cut to fit the magnet)
Modeling clayPROCEDURE:
Plug one end of the straw with clay, and fill the straw three-quarters full with iron fillings.
Plug the other end with clay.
Lay the iron-filled straw on the magnet for at least one minute.
Being careful not to shake the straw, pick it up and move it near the compass.Observe any movement of the compass needle.Now shake the straw several times, and again hold the straw near the compass.Observe any movement of the compass needle.RESULTS:
- The compass needle is attracted to the straw before the straw is shaken, but there is no movement of the compass needle after the straw is shaken. This is because the iron fillings became magnetized when brought near the magnet, and the magnetic domains in the iron fillings lined up. Shaking the straw rearranges the pieces of iron, causing the magnetic domains in the iron to be randomly arranged, and magnetic lines of force cannot form.
Back to Grade School Table of Contents
Back to Lab Dad's Laboratory
- The compass needle is attracted to the straw before the straw is shaken, but there is no movement of the compass needle after the straw is shaken. This is because the iron fillings became magnetized when brought near the magnet, and the magnetic domains in the iron fillings lined up. Shaking the straw rearranges the pieces of iron, causing the magnetic domains in the iron to be randomly arranged, and magnetic lines of force cannot form.
WHAT MAKES A MAGNET A MAGNET?
INTRODUCTION: