Sunspots are magnetic features in the photosphere of the Sun that appear darker than their surroundings. In sunspots, the process of convection is altered by the presence of strong magnetic fields, which do not allow the bubbles of hot gas coming from the interior of the Sun to emerge normally. For this reason sunspots are cooler (up to 2000 C) and darker than the quiet Sun.

Sunspots consist of a central dark area called umbra, and an outer brighter ring named penumbra with a filamentary appearance. While the umbra has strong vertical magnetic fields, the penumbra has weaker fields which bend until they are nearly horizontal. Sunspots can be observed in many different sizes and shapes, from round to elongated, and from a size of a few thousand km to monster sunspots of up to 100 000 km of diameter. They can last days, weeks, or even several months. 
Title: Sunspots

Eirik Krogh Wetterhus
Anders Nordbø
Simon B. Nielsen
Emil Lund Wøien

Teacher: Hossein Rostamzadeh
School: Asker videregående skole (Norway)
Title: Sunspots

Claudia García Díaz
Natalia Guzmán Marcos
Ruth Hidalgo Iglesias
Andrés Rodríguez Bernardo

Teacher: Julián Elvira García
School: Colegio Zazuar (Spain)
Title: Sunspots

Albert Haase
Tom Hübner
Joel Holz
Maximilian Hoppenrath

Teacher: Johannes Löhner-Böttcher
School: Hansa-Gymnasium Stralsund (Germany)
Title: Sunspots

Chrysa Vlachaki
Aikaterini Giannakopoulou
K. Diamantopoulou
Marios Koursaris

Teacher: Maria Magkanari
Title: The sunspots

Elena Morales Fernández
Andrea Pérez Conde
Sofía Parrilla Fuentes
Carmen Santiago Pérez

Teacher: Juan Torrecillas Toro
School: IES Francisco Ayala (Spain)
Title: Sunspots

Francesco Brogna
Matteo Angher
Ariele Zullo
Giacomo Schiavoni

Teacher: Alberto Bigazzi
Title: What are sunspots?

Emily Stift
Levin Franke
Philip Starz

Teacher: Rainer Rene Prokopec
Title: The Sun: sunspots and magnetic fields

Denise Buftea
Mattia Mare
Simone Staccone

Teacher: Rocco Torre
Title: Sunspots

Federico Di Crescenzo
Salvatore Mammarella
Natalia Dantese
Camilla Marinelli

Teacher: Laura Lamonea
School: Liceo Scientifico A. Volta (Italy)
Title: The sunspots

Alessandro Bartoli
Serena Dagosta
Alessia Guglielmino
Giacomo Vaccaro

Teacher: Giuseppina Balsamo