In ancient times, people learned that pieces of iron ore mined near the city of Magnesia can attract iron objects. This amazing property was called magnetism by the name of the city, and pieces of ore - magnets. Many centuries have passed since then. Time and wars destroyed the city of Magnesia, and goats graze in the hills where he stood.... With the help of this book, in a school workshop, you can make working models of electric and steam engines. For middle school students.