The image shows an imprint of a child's hand (10 years old) on an agar plate as it looked after 3 days. The boy ate sauerkraut with his hand, then wiped it off with a paper towel and imprinted the hand. Bacteria transferred from the hand onto the agar plate developed into light-colored colonies. This experiment shows how bacteria are transferred from hands to other objects touched and why it is important to wash one's hands to avoid the transfer of microorganisms.