8th grade · Science · Unit 5 of 11
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.
New York State Learning Standards 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.
- Some forces act without touching: gravity, magnetism and electric force.
- Gravity always attracts and is stronger with more mass. Electric and magnetic forces can push or pull.
- 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 New York
In the New York State Learning Standards, this is unit 5 of 11 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.
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
An electromagnet is made by…
- rubbing a balloon
- freezing a magnet
- running current through a coil of wire
- heating a rock
running current through a coil of wire
Hint: Electricity makes magnetism.
Question 2
A field is a region where…
- an object feels a force
- nothing happens
- it's always hot
- only light exists
an object feels a force
Hint: Fields act at a distance.
Question 3
Like magnetic poles…
- do nothing
- repel
- attract
- melt
repel
Hint: North pushes north.
Question 4
Increasing current in an electromagnet makes it…
- weaker
- reversed in mass
- unchanged
- stronger
stronger
Hint: More current, stronger field.
Question 5
Like electric charges…
- disappear
- attract
- repel
- become neutral always
repel
Hint: Positive pushes positive.
Question 6
Which change makes the electric force between two charges stronger?
- Increase the charges
- Make them neutral
- Paint them
- Increase the distance
Increase the charges
Hint: More charge, more force.