  Smartphone is a powerful internet connected computer packed with internal
sensors that measure sound, light, acceleration and magnetic field strength.
Physics teachers can use them as measurement devices to demonstrate science
concepts and promote the joy of learning. Some research has also shown the
benefits of using smartphones for teaching and learning physics. This article
aims to extend mobile phone research with our open source apps and low-cost
experimental design. The three experiments that we designed include
radioactivity, line spectrum, standing sound wave and polarization of light.
Students are able to conduct experiments and collect data easily without using
bulky data loggers or laptops. Substituting a data logger with a smartphone
will mean that every student can possess his/her own measuring tool inside and
outside the classroom, instead of having to share with a large group of
students in a scheduled lab. By empowering the students to conduct their own
experiments and collect data, the use of the smartphone as a tool aims to
support student learning anytime and anywhere, igniting greater joy of learning
