Bruco: a video game to learn the periodic table

Creation of the software

The program was written by using the Processing v.3.5.4 integrated development environment (IDE).¹⁰ Processing is a free software useful for visual arts programming and the programs written could work on different platforms. Processing is compatible with the several programming languages, from Java to HTML5. Our program is written in Java 9 and it works by using the built in 2D renderer without additional libraries. The main characteristics of this environment is the presence of a startup() function, called once at the beginning of the game, and a draw() function, called automatically at every cycle respecting the framerate. The game board is represented internally by a square matrix and the caterpillar is drawn each frame by using simple drawing routines such as circles and lines. The number of horizontal squares grid is calculated by dividing the horizontal resolution by 50. The screen is updated with a framerate of 15 frames per second in full screen mode. This framerate is chosen in order to have a balance between speed and playability. The minimum requirements for a smooth game is a PC with an output resolution of 1920×1080 pixels (Windows 10 with 2 GHz central processing unit (CPU) and 8 Gb of rapid access memory (RAM)). The program automatically sets the number of grid squares for different screen resolutions but at higher resolution the number of empty squares overtake the filled thus rendering the game less appealing due to the time needed to reach elements. When the program starts the image start.png is shown together with the list of the top 10 players in an arcade-style. This allows the customization of the starting image, but remembering that the central part will be overwritten by the game while printing the list of players.

The possibility to have the score indicated in the top 10 list is intended to increase the motivation of the players to achieve better and better results. The introduction page of the game together to the top 10 can be seen below in the Figure 1.

Figure 1. The introduction of the periodic caterpillar video game.

Some variables could be used to change the game appearance such as grid size (in pixels) and are commented in the code. Players can control the caterpillar by using the letters w, a, s, d for, respectively, up, left, down and right directions.

The arcade joystick with microswitches (Tongmisi 8 Way Arcade Joystick with Microswitch for Arcade Game Console) was connected to the Arduino Leonardo directly on four digital inputs, D9-D12. The pin “D9” was used to emulate “d”, “D10” was used to emulate “a”, “D11” was used to emulate “s”, “D12” was used to emulate “w”. The schematic representation of Joystick is shown in Figure 2, while the firmware code is inserted in a public repository.¹⁸

Figure 2. Schematic representation of Joystick.

Superiority of periodic caterpillar game

After having recognized an element as it appears on the periodic table or as a part of a group or period, we hope that the player tends to remember the answer even in the following sessions. In this present work, the specialty of the game is that it could be potentially applied for team building purposes on different levels, from the encouragement to team working in school classes and/or with students, to different areas of interest as it could be a lab environment, in which members must learn or to improve their ability to work in teams or small groups.

Gameplay

The game begins with a small caterpillar that starts moving on the screen. The player can control it across all the board. During the game, element symbols appear randomly on the screen. At this point, a sentence appears at the bottom of the screen, requesting that the player “eats” a specific element. The request could correspond to an element symbol, period, group, block (s, p, d, f orbitals) and type (alkaline, alkaline-earth, etc.). In the bottom-left corner a graphical representation of the periodic table helps to find the required element. While eating the elements, the caterpillar grows longer and longer. Compliments¹⁷ like: ‘good’, ‘great’, ‘beautiful’, ‘keep it up’, ‘yum’, ‘nice shot’, ‘very well’, ‘go strong’, ‘prominent’ and ‘you’re myth’, for each correct answer is designed to promote pleasure when the correct element is taken which are shown in Figure 5.

The game also comments for wrong elements like: ‘oh no’, ‘ops’, ‘caution’, ‘look what is required’, ‘watch out’, ‘error’, ‘this was not to eat’, ‘mistaken’, ‘concentrated’ and ‘look at the table well’. In the latter case, one life is decreased from the starting five. These remarks are designed to help the player to be the best.

After each element is eaten, from one to three new elements appear on the board. Thus, the probability to find the correct element decreases while the probability of failure increases. Every five elements taken the game speed increases up to a maximum when the elements taken are 15, rendering the playability more and more difficult. The faster the correct elements are taken by the player, the higher the probability that a life bonus appears on the board. This happens if we collected at least two elements since the last bonus and random(300)>float (time Bonus/elements Since Last Bonus).

When time between successes is greater than 1500 cycles (about 100 seconds), correct elements are highlighted. This helps beginners (people new to periodic table) to go ahead in the game but they have a reduced life bonus (see Figure 5, bonus lives) probability. The game ends when the player finishes the lives, or the caterpillar bites itself.

This game is very versatile and can be exploited in many ways. For example, a good method to use periodic caterpillar game with students is divide the class into groups that contains 2 to 4 players and give to them a periodic table (see Figure 4). One team member controls the caterpillar, and the others help him suggest the right elements to eat. Each group will be able to play until the “game over”, finishing all their available lives. The team that achieves the highest score win the game.

Aim of the project

The purpose of the game is simple: to explore the periodic table. Finding the chemical elements location, their groups, periods, symbols and in some cases their mere existence are parts of this exploration (see Figure 3).

Figure 3. Schematic representation of the video game to learn the periodic table.

Figure 4. Illustration of the video game periodic caterpillar as team.

Figure 5. The comments of the game appear on the screen when playing.

The team play, especially with two players, where the one controlling the caterpillar and the other suggesting elements (with the help of a periodic table). For example, in a specific case, the student could move the caterpillar with the help of a joystick under the suggestion of an adult.

Experience with the game

The video game was shown during the European Researchers’ night held in Pavia (Italy) on 27^th September 2019. People were attracted while seeing the graphic of the game and they immediately liked the gameplay. The number of players increased quickly because this game is kind of magnetic that will rush you to help your friends with suggestions. The important point we observed is that it is not limited only to some groups of known friends, even complete strangers started to help each other during the match without being familiar.