Tasha Sturm, a lab technician at Cabrillo College in California, has created an extraordinary set of images that illustrate the diverse world of microbes that lives on our skin. This colorful petri dish is full of bacteria, yeast, and fungi that were found on her 8-year-old son’s hand after he finished playing outside.

Sturm explained the process on Microbe World, where she posted the images. She used tryptic soy agar, which forms a nutritious jelly perfect for growing microbial cultures. After her son pressed his hand gently into the gel, she incubated it and let the bacteria flourish for a few days. Though the resulting petri dish should be treated as a biohazard, it should also be noted that having both harmful and good bacteria on your hands and skin is normal. To the displeasure of germaphobes though, exposure to safe amounts and types of bacteria ensures a healthy ‘microbiome,’ immune system and digestive tract.

The different visible structures of these bacterial colonies grown in the handprint reflect their microscopic characteristics. Microbes with and without protective membranes or flagella (which allow them to swim) will all create colonies of different colors, shapes, textures, and sizes.

More info: microbeworld.org (h/t: colossal)