NEW YORK — More than 900 middle schoolers are showcasing science projects on topics from monkey grooming to solar ovens at a New York City museum.

The American Museum of Natural History says Saturday’s event is the city’s largest middle school science expo. It features more than 400 student projects.

Subjects include the effects of fidget spinner toys on controlling stress, using body heat to generate electricity and studying the effect of water from the polluted Gowanus (goh-WAH’-nuhs) water on the health of seaside goldenrod plants.

Other projects examine the effects of stress on test scores and the grooming habits of spider monkeys.