Introduction

Crosswords puzzles have been around in different forms since Egyptian times and their popularity continued to build throughout the rest of the years. Today, most daily newspapers as well as many magazines include a crossword puzzle and, in fact, there exist a number of magazines and books containing only crossword puzzles that can be easily found in any magazine racks.

Educational Value

Crossword puzzle solving involves several useful skills. Some of them are:
- Puzzle solving is a much more active type of learning, and will engage students with the material more than passive types of review techniques do.

- To solve any crossword puzzle, students must know specific vocabulary, reasoning and spelling.

- Students must be able to identify and understand the terms being used and word attack skills.

- Students need to make inferences, evaluate different choices and drawing conclusions.

- Visual learners often have strong puzzle-solving skills, and feel great satisfaction when they complete one.

- Permits acquiring new vocabulary or terminology and also involves making differentiations between similar words or phrases.

How to create specific crosswords puzzles?

The advent of the internet age gave educators access to any number of online programs that will help students to learn. See, for instance the following chemistry databases:
http://www.rsc.org/, http://www.chembiogrid.org/ related/resources/databases.html, http://www.chem.ox.ac.uk/cheminfo /internet.html, http://www.chemweb.com/, The WWW Virtual Library (http://www.vlib.org/

Among them, there are a number of programs that create puzzles geared to their student’s particular subject. Puzzle creation software and websites are abundant, and easy to use, so teachers can create curriculum-specific crosswords with little trouble. We propose as crosword generator the (free) Hot Potatoes suit, with which one can easily create different interactive activities which can be accessed on-line through Internet. Pages are automatically created by employing the HTML and JavaScript protocols, some of them with Through the Hot-Potatoes web page (http://web.uvic.ca/hrd/halfbacked/). Manuals and instructions are available in different languages.

Whether you are studying history, languages, biology or chemistry, a crossword puzzle with subject-specific vocabulary can be created with ease and in a short amount of time.

How to work with puzzles?

Probaly the most striking educational aspect of crossword puzzles is how you must think using several parts of the brain at once: definitions, spellling, synonyms. One can easily prepare a number of different crossword puzzles created to printout on the same topic. Each one may be unique so that when we are studying a topic of chemistry, say Nuclear Magnetic Resonance (NMR) one can easily print out 3-6 different crossword puzzles on the same topic, split the class into 3-6 groups and give them each a different crossword puzzle.

Here we provide an example of one easy crossword specifically prepared for undergraduate students learning NMR.