Real-time experiments approach in kinematics using ComLab equipment

Real
-
time experiments approach
in kinematics using ComLab
equipment


Tine Golež, St. Stanisalv institution for education,

Ljubljana, Slovenia


ComLab Conference 2007

Computerised laboratory in science and technology education

30. November in 1. December, 2007 Radovljica, SLOVENIJA

Kinematics

(using comLab software)


Physics



Graphs based approach;
comprehension before
computation


... and an additional
outcome...


Mathematics



Calculus; precursor
for calculus

(Prematurely) equations approach

v = v
0

+ at

x = x
0

+ v
0
t + at
2
/2

v
2

= v
0
2

+ 2ax


... Followed by calculatin tasks

Fig. 1. A student has walked in front of sonic sensor. The x(t) graph is
displayed.


(1.4 s,
-
0.40 m)

(5.2 s, 0.80 m)

Figure 2: The slope of the curve
x(t)

is defined as the slope of the
tangent at that point. The calculated slope at t = 4,0 s equals the
instantaneous velocity at that instant (
D
x/
D
t = 0.32 m/s). Graph
v(t)

confirms the result. The reverse process is shown on
v(t)

graph. The
displacement during time interval is determined by calculating area
(in our case
D
x = 1,0 s∙0,45 m/s = 0,45 m)


(1.4 s,
-
0.40 m)

(5.2 s, 0.80 m)

Figure 2: The slope of the curve
x(t)

is defined as the slope of the
tangent at that point. The calculated slope at t = 4,0 s equals the
instantaneous velocity at that instant (
D
x/
D
t = 0.32 m/s). Graph
v(t)

confirms the result. The reverse process is shown on
v(t)

graph. The
displacement during time interval is determined by calculating area
(in our case
D
x = 1,0 s∙0,45 m/s = 0,45 m)

Figure 3. An ordinary ball was held under the motion sensor and dropped
from rest. It rebounded twice from the floor during the measurement.
Graphs show that the instantaneous speed (which is equal to the
magnitude of the instantaneous velocity) at points of equal elevation in
the path is the same whether the ball is moving upward or downward
during one rebound (e. g., compare t = 0.80 s and t = 1.40 s). In addition,
during one rebound the ball slows from the initial upward velocity to zero
velocity. At the highest point it changes its direction of motion. Certainly, it
experiences the same acceleration on the way down. The acceleration,
which is the rate of change of velocity, is constant. Therefore this part of
v(t) graph is linear. The slope of the line equals the acceleration. As
calculated for this case:



Figure 4: Motion sensor
analyzed pendulum
motion. The graphs
x(t)
,
v(t)

and
a(t)

are not
displayed in this order.
Students must find out
the legend of each graph
by investigating their
slope and iterrelationship
between the graphs.

ScienceMath Project

•
Comenius 3 years project, (Germany, Finland,
Danmark and Slovenia
–

4 Universities and 4
high schools)

•
The project ScienceMath is an interdisciplinary
European co
-
operation project for the promotion
of mathematical and scientific literacy. Objective
is the development of proven teaching
sequences and
–
modules that lead to a
comprehensive and multidimensional learning of
mathematic contents and concepts. It is the
basic idea to encourage mathematic learning in
scientific contexts and activities of the pupils.

Back to ComLab product

•
Evolution and growth

•
European vision

•
Lisbon strategy

•
Teacher as a role model








Photo:T. Golež