The use of physical computing devices as teaching tools presents several challenges for educators and learners. Most introductory programming environments help to learn programming by removing the possibility of syntax errors,
usually by using a visual programming language. However, understanding syntax
is just one aspect of the learning process. One of the most challenging tasks for
students is to build a correct mental model of the underlying machine model and its
execution dynamics. Additionally, visual programming languages present issues
when transitioning to text-based languages. In this paper we present Physical Bits,
a web-based programming environment for educational robotics that attempts to
solve these issues by providing a live programming experience using both visual
and textual programming languages.