Dynamic Visualizations
Dynamic visualizations are those in which the graphical elements being
displayed can change with time. The most obvios type of dynamic
visualization is a simulation (here the term simulation refers to both
the underlying calculation of parameters and the mapping of those
parameters to visual entities. Simulations can take many forms and
different types of learning can take place given the form of
simulation. In general learning can occur by two means of interaction
with a simulation
- Writing the simulation
- Dynamically interacting with the simulation during its execution
An example of a simulation where the student learns by writing the
simulation is Logo. Logo was designed to allow students to explore
goemetrical relationships. It consisted of a small triangle called the
"Turtle" that could be moved about on the screen using commands(the
original "turtle" was actually mechanical and moved about on the
floor). The turtle could be told to move foward by some amount, turn
left, turn right, put its pen up or down. If the turtle moved with its
pen down a line would be drawn on the screen tracing its movement. The
commands could be combined to form procedures, and could be stored and
run sequentially in the form of a program. By having to achieve
certain tasks, draw a triangle, square, pentagon, ..., with the turtle
the student was required to apply knowledge about the geometry of the
shapes. If the student did not have the needed knowledge Logo served
as an environment for the student to explore the relationships between
length of a side and the angle of intersection in the shapes. Logo
also served as an introduction to programming. Although the language
was very simple, it introduced the ideas of iterative execution and
functional decomposition.
An example of a simulation where the student learns by dynamically
interactiong with the simulation is the Dynaturtle, diSessa[4]. The
Dynaturtle is a similar envirnoment to Logo. One major difference is
that insted of usinf the forward command, student put the turtle in
motion by applying impulses or "kicks" to it in the direction it was
facing. Expirements would be set up in which the student would be
required to have the dynaturtle hit a target. The arrangement of the
expiremnt would be such that the dynaturtle could not be aimed
directly at the target. In order for the student to achieve the goal
they would have to display an understanding of Newtonian mechanics
that is in conflict with there intuitive Aristotelian view of physics,
diSessa[4]. This environement allowed the student to form and test
hypothesis' about the environment. Through such expirements and
careflu guidence from the instructor the students were able to
construct there own knowledge about the world consistant with the
Newtonian ideas being taught.
Simulations can also display multiple representations of the same
concept. By linking the changes in one representation to the
appropriate changes in the others, A student is able to manipulte the
environment in a context in which they are familiar and whitness the
effects those manipulations have on the other representations.