  Technological advances offer the possibility of using mobile devices to
enrich learning environments with multimedia content. Although physical
experiments play a key role in science learning, little is known about
integrating multimedia learning in physical experimental processes, especially
in real classroom settings. In our approach, students use tablet PCs to
investigate motions with an application providing multiple representations of
the measurement data. We present the results of a cluster-randomized controlled
trial (N=262 matched samples) that covered the topic uniform motion. The
results show that the treatment not only leads to a significant reduction of
extraneous cognitive load (F(1,240)=27.01, p<10-3, ${\eta}$2=0.101,
$1-{\beta}$=1.000), but also to greater conceptual knowledge (F(1,259)=10.82,
p=0.001, ${\eta}$2=0.048, $1-{\beta}$=0.953). Structure equation modeling
statistically supports the assumption of a causal relationship between the
reduction of extraneous cognitive load and the increase in conceptual
understanding.
