The theme is in the upper left hand corner, the words to be associated ­ or not associated ­ with it, in the upper right hand corner.

A reminder of former concepts that would be needed to grasp the new one, are placed under the theme.

The description of the theme, under "Now:", would be explained by sign before it was written.

Then a further description, most often with a drawing, would follow: (see fig. 2)

 

 FIELD

Forces can be said to set up fields

  a field on a farm
a field of war
a field of interest

Recall:

When one body attracts or repels another body (Newton 3), there is a force between the two bodies.

Forces are vectors , they have direction.

Now:

If a body will attract or repel any body with similar characteristics, as the Earth will attract all masses, we can think of the body (the Earth) as surrounded by a field of force.

   
To represent this field, we make drawings.
The direction of the force is indicated by the field lines
The strength of the field (the force on 1 kg mass) at a given point, is indicated by the density or spacing of the field lines.

 


Figure 2:
The blackboard later in the lesson