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8th grade · Science · Unit 4 of 7

Fields & Forces at a Distance

Gravity, magnetism and electric forces.

What your child practices

Practices forces that act without touching: what affects electric and magnetic force strength, why gravity is always attractive and depends on mass, and how fields store energy.

Maine Learning Results learning standard: MS-PS2-3; MS-PS2-4; MS-PS2-5 · electric, magnetic and gravitational forces that act at a distance

How we explain it

Children can open this short lesson before they practice.

  1. Some forces act without touching: gravity, magnetism and electric force.
  2. Gravity always attracts and is stronger with more mass. Electric and magnetic forces can push or pull.
  3. More current makes an electromagnet stronger; closer objects feel stronger forces.

Example: A rubbed balloon sticks to a wall. Which force is this? Rubbing moves electrons onto the balloon. Charged objects attract. Answer: static electric force

Fields & Forces at a Distance in Maine

In the Maine Learning Results, this is unit 4 of 7 in 8th grade Science, after Kinetic & Potential Energy and before Genes & Heredity.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Maine Department of Education

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Adding more coils to an electromagnet makes it…

    • weaker
    • stronger
    • lighter
    • colder

  2. Question 2

    Gravitational force is always…

    • attractive
    • zero
    • repulsive
    • sideways only

  3. Question 3

    Increasing current in an electromagnet makes it…

    • stronger
    • reversed in mass
    • weaker
    • unchanged

  4. Question 4

    Opposite magnetic poles…

    • glow
    • repel
    • cancel mass
    • attract

  5. Question 5

    An electromagnet is made by…

    • freezing a magnet
    • running current through a coil of wire
    • heating a rock
    • rubbing a balloon

  6. Question 6

    Earth has a magnetic field because of…

    • the moon
    • moving molten iron in its outer core
    • trees
    • the ocean

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