Abstract:

Background:
Computer science education for kids has received considerable attention in recent years. In fact, many visual languages for kids has recently developed, such as ScratchJr. Although computer science has a wide range of sub-fields, we assume that it consists of the following three basic fields: computational science, such as programming, and informational science, such as digitization, and artificial intelligence, such as machine learning. This is because our university offers computer science education for first-year students based on the assumption.

Fourier Transform:
From this assumption, the recent attention mainly focuses on topics in computational science, but not those in information science, which is one of the fundamental theory of computer science. The author has already developed classes on informational science for students from elementary school to university. A big feature of these classes is that the author tries to deliver core ideas of the Fourier transform, which decomposes a function into simpler trigonometric functions. To understand the Fourier transform, it is necessary to have various mathematical notions, such as trigonometric functions, infinite sequences, and integral calculus, and thus it is too difficult for young kids to learn the Fourier transform. However, despite of the difficulty, we can use many equipments, such as prism, and thus students can learn ideas of a difficult theory through physical experiences of many phenomena related to sound and light because the Fourier transform corresponds to the superposition principle.

Motivation:
The author has an interesting learning equipment, called water pearl, which makes us confuse that droplets of dropping water is climbing up when we see it through flashing light. This phenomenon happens when two frequencies of dropping and flashing are appropriately selected, and is closely related with the sampling theorem, an important theorem in information theory. Thanks to this mysterious phenomena, most students like to see it. However, this is not incorporated the classes the author developed since it is necessary to explain notions of the wave and its frequency.

Goal:
In this paper, the author shares experiences to extend the developed lessons to those with the sampling theory and water pearl, and experiences of a class and an event of science fair for junior hight school students and elementary school kids. The main idea of the extension is that we use "timing" instead of waves and frequencies.

Hands-on Experience:
Like computer science unplugged, these lessons are designed to put students through hands-on experiences with many materials, including water pearl, in addition to already developed ones, such as a JavaScript application with HTML5 and CSS technologies (https://rebrand.ly/486fe).

Keywords:

Information Theory, Fourier Transform, Sampling Theorem, JavaScript, Average, Vector Space, Inner Product.