| dc.description.abstract | Visualizations within physics education are critical for learning physics and can be
realized in a classroom with experiments, demonstrations, digital tools, mathematical
analysis, or other representations, all with different levels of abstraction. This
project aimed to determine whether the concept of field (i.e. electrical, acoustic, or
optical fields) can be demonstrated, visualized, and applied in various experiments.
In the first Paper, an experimental setup for visualizing charge particles’ motion
in an electrical field was built. Designed learning activities were performed, and
the effects on Swedish upper secondary school students’ conceptual understanding
were tested. This work shows that students’ understanding of the interaction
of charged particles with electrical fields increases more than without if a lecture
includes an experiment that visualizes the phenomenon, either live or videotaped.
In Paper II a remotely operable optical trap was realized and used to levitate and
investigate charged droplets remotely from a classroom. Visualizing and measuring
many fundamental physical processes are described. The motion of charged
particles in electric fields and the photon pressure of light is described as well as
how it can be safely demonstrated for a class.
In Paper III, an optical trap is used to visualize the electron´s quantization. In this
work, it was shown that the effect of a single electron addition can be magnified
and observed by the naked eye and measured with a ruler analogous to Millikan’s
experiment. The droplet is optically trapped and uncharged in an alternate electric
field by an alpha radiation source. A strong electrical field was applied and as the
uncharged droplet gained charges from the ionized air it jumped a well-defined
step depending on how many electrons were added. The smallest jump corresponds
to the addition of one electron, i.e. one elementary charge, and longer
jumps are multiples of this.
Finally, in Paper IV, a new type of experimental method to determine the volume
of microliter-sized droplets in acoustic fields is described. By using a simulation
of the acoustic field to assist in setting the cavity length a fast and self-calibrated
method is presented. | en_US |
