8th grade · Science · Unit 4 of 10
Circuits & Static
Circuits, conductors and static charge
What your child practices
Complete circuits, series versus parallel wiring, conductors and insulators, adding cell voltages, and static electricity (like and opposite charges, lightning).
Minnesota K-12 Academic Standards benchmark: 8P.1.1.1.2 · what affects the strength of electric forces
How we explain it
Children can open this short lesson before they practice.
- Current flows only around a complete, unbroken loop.
- A series circuit has one path, so one broken bulb stops them all. A parallel circuit has several paths.
- Static charges: like charges push apart, opposite charges pull together.
Example: A parallel circuit has 3 bulbs. One burns out. How many stay lit? In parallel, each bulb has its own path. The other paths are still complete. 3 − 1 = 2. Answer: 2
Circuits & Static in Minnesota
In the Minnesota K-12 Academic Standards, this is unit 4 of 10 in 8th grade Science, after Atoms & Elements and before Fields & Forces at a Distance.
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
What does a circuit breaker or fuse do?
- It stores power during a blackout
- It adds extra current when needed
- It turns AC into sunlight
- It breaks the circuit if too much current flows, preventing overheating
It breaks the circuit if too much current flows, preventing overheating
Hint: Too much current makes wires hot. A breaker 'trips' to open the circuit before that becomes dangerous.
Question 2
Each cell gives 1.5 V. If 6 cells are connected in series (end to end), what is the total voltage?
🔋🔋🔋🔋🔋🔋answer boxV
9 V
Hint: Cells in series add their voltages: 1.5 V × 6.
Question 3
Conductor or insulator? Sort each material.
Sort into: ⚡ conductor · 🚫 insulator
- 🥄steel spoon
- 🔩iron nail
- 🧶wool yarn
- 🌊salt water
- ✏️graphite pencil lead
- 🪵dry wood
- 📏plastic ruler
- 🪟window glass
⚡ conductor: steel spoon, iron nail, salt water, graphite pencil lead · 🚫 insulator: wool yarn, dry wood, plastic ruler, window glass
Hint: Conductors let electric current flow easily (most metals, graphite, salt water). Insulators block it (plastic, rubber, glass, dry wood).
Question 4
A parallel circuit has 3 identical bulbs and a battery. One bulb burns out. How many bulbs stay lit?
💡💡💡answer box
2
Hint: In a parallel circuit, each bulb is on its own branch. The other branches are still complete, so those bulbs stay lit.
Question 5
After you walk across a carpet, you feel a tiny shock when you touch a metal doorknob. Why?
- Charge built up on your body jumps to the metal
- The doorknob is plugged into the wall
- The carpet is a battery
- Your shoes are magnetic
Charge built up on your body jumps to the metal
Hint: Walking on carpet rubs electrons onto (or off) you. Metal is a conductor, so the charge jumps across as a spark.
Question 6
Two balloons both have a negative charge. What happens when you bring them close?
🎈- They both become positive
- They push apart (repel)
- They pull together (attract)
- Nothing happens
They push apart (repel)
Hint: Like charges repel; opposite charges attract.