It is an easy level crochet project, made with the amigurumi technique. All parts are done in continuous rounds.
The oxygen atom is a closed ball, while hydrogen atoms are made as little caps. Once finished, hydrogen atoms are sewed to the oxygen atom with a whip stitch in specific places, to emulate the molecular union.

Final size: about 4.25 cm (1.7 inches).

•Cotton yarn, DK (about 12 WPI, or any yarn you want to use), color A (about 20 g for DK yarn) and color B (about 10 g for DK yarn)
• Stuffing (e.g. fiberfill)
• 6 mm safety eyes (optional)
• C (2.75 mm) crochet hook (if you use another yarn, use a suitablehook for it. Stitches should be tight to prevent filling from popping out of your project).
• Stitch marker
• Yarn needle
• Pins
• Scissors