8th grade · Science · Unit 14 of 16
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).
Alabama Course of Study content standard: 8.16 · how electrical energy is transferred in circuits and changed into other forms
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 Alabama
In the Alabama Course of Study, this is unit 14 of 16 in 8th grade Science, after Work, Energy & Efficiency and before Light & Radiation.
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
Each cell gives 1.5 V. If 3 cells are connected in series (end to end), what is the total voltage?
🔋🔋🔋answer boxV
4.5 V
Hint: Cells in series add their voltages: 1.5 V × 3.
Question 2
Why are the lights in a house wired in parallel?
🏠- So one switch turns off every light at once
- Parallel circuits need no power source
- It makes every bulb dimmer to save energy
- Each light can work even if another is switched off or burns out
Each light can work even if another is switched off or burns out
Hint: In parallel, each light has its own branch, so it doesn't depend on the others.
Question 3
Conductor or insulator? Sort each material.
Sort into: ⚡ conductor · 🚫 insulator
- 🧤rubber glove
- 🔌copper wire
- 🪵dry wood
- 🥄steel spoon
- 🪟window glass
- ✏️graphite pencil lead
- 📏plastic ruler
- 🌊salt water
⚡ conductor: copper wire, steel spoon, graphite pencil lead, salt water · 🚫 insulator: rubber glove, dry wood, window glass, plastic ruler
Hint: Conductors let electric current flow easily (most metals, graphite, salt water). Insulators block it (plastic, rubber, glass, dry wood).
Question 4
Lightning is a giant example of…
🌩️- static electricity discharging
- a series circuit
- sound energy
- a magnet being switched off
static electricity discharging
Hint: Charge builds up in storm clouds, then jumps through the air in a huge spark.
Question 5
A series circuit has 6 identical bulbs and a battery. One bulb burns out. How many bulbs stay lit?
💡💡💡💡💡💡answer box
0
Hint: A series circuit has only one path. A burnt-out bulb breaks that path, so the current stops everywhere.
Question 6
Which part of a circuit is the source of electrical energy?
🔋- the bulb
- the switch
- the battery
- the wire
the battery
Hint: A battery (or cell) pushes the current around the circuit.