The grain food group is the orange part of the new MyPlate and the Food Pyramid. Our printables feature fun worksheets, activity sheets and coloring pages to help children learn about the foods that belong to this food group and how it helps their body.
A magnet keeper, or armature is a ferromagnetic bar made from soft iron or steel which is placed across the poles of a permanent magnet to help preserve the strength of the magnet by completing the magnetic circuit; it is particularly useful for magnets which have a low magnetic coercivity, such as Alnico magnets. magnet keeper, or armature is a ferromagnetic bar made from soft iron or steel which is placed across the poles of a permanent magnet to help preserve the strength of the magnet by completing the magnetic circuit; it is particularly useful for magnets which have a low magnetic coercivity, such as Alnico magnets.
All permanent magnets exhibit what scientists call ferromagnetism, when a magnetic field produces a strong attractive force in the metal. Under the right conditions, a ferromagnetic metal piece acquires its own field, becoming magnetized.agnetic Circuit. A magnetic field holds its strength best when the entire magnetic loop, or circuit, passes through a ferromagnetic metal at all points. A horseshoe magnet has an air gap between its two poles; the keeper closes this gap. A bar magnet, left by itself, will lose its strength over several months.