Final answer:
Health teaching is the public health intervention being implemented when a nursing student develops a teaching plan about hand washing to present to a group of elementary school children.
Step-by-step explanation:
The public health intervention being implemented when a nursing student develops a teaching plan about hand washing to present to a group of elementary school children is health teaching. Health teaching involves providing education and information to individuals or groups with the aim of promoting and improving their health. By teaching the children about hand washing, the nursing student is helping to prevent the spread of diseases and promoting good hygiene practices.