Definition:
    A magnetic field is an invisible force that attracts metal and can pass through air, water, wood and paper.

Characteristics:

1.  A magnetic field is a force that acts on metals.

2.  A magnetic field is invisible.

3.  A magnetic field can pass through certain substances (e.g:  wood, paper, water, air).
 

Examples:

1.  Show magnet pulling and pushing paper clips by using both poles of the magnet (to show that it's a force that acts on metal).

2.  Tie paper clip to string and tape other end of string to desk.  Lift up paper clip with magnet, eventually moving magnet slightly beyond the reach of the string.  Paper clip and string will be standing up straight (to show invisibility of force).

3.  Put paper clips on top of glass, magnet underneath.    Also demonstrate with plywood piece, students' hands, piece of thin plastic, paper plate, bowl of water, etc...  (to show that force can attract metals through certain substances).
 

Open-Ended Questions

1.  What do you observe when I change directions of the magnet?

2.  What can you see happening with the string, the paperclip and the magnet?

3.  What happens when I move the magnet under the glass (or other substance)?
 

Convergent Questions

1.   So what kinds of actions can a magnet make a paper clip do?  What does that tell us?

2.  What is going on here with the magnet?  It's not touching the paper clip!   How can that be?

3.  So which of these substances can a magnet's force go through?  Why do you think that happens?
 

Superordinate Concept:  Forces of Nature
Coordinate Concept:  Gravity
Subordinate Concept:  Identifying composition of common objects (e.g: metals, woods, paper...)