If the pencil had an eraser would it have the same results?

Rubber is an insulator. With the amount of power generated here, you wouldn't see any result at all. Some high voltage stuff can overcome the insulation properties of rubber (which is why people that work on power lines can't just use rubber gloves) but that's incredibly unsafe for experimentation.

What is the fluid he pours into the cup?

Actually, you're both right: it's hot acid with added salt. The stuff he pours from the cooker is hot vinegar, and he adds a spoonful of salt. Both make the vinegar a better conductor.

Main content

Course: High school physics > Unit 12

Lesson 5: Discovery of resistors

Pencil resistor

Name: Pencil resistor
Uploaded: 2013-04-23T00:46:04Z
Description: A pencil causes a change in the deflection, similar to the effect of adding an electromagnet. Why?

Google Classroom

A pencil causes a change in the deflection, similar to the effect of adding an electromagnet. Why? Created by Brit Cruise.

Want to join the conversation?

Sort by:

Alex
Posted 10 years ago. Direct link to Alex's post “If the pencil had an eras...”
If the pencil had an eraser would it have the same results?
Button navigates to signup pageButton navigates to signup page
(3 votes)
Answer
- Stephen Brand
  Posted 10 years ago. Direct link to Stephen Brand's post “Rubber is an insulator. W...”
  Rubber is an insulator. With the amount of power generated here, you wouldn't see any result at all. Some high voltage stuff can overcome the insulation properties of rubber (which is why people that work on power lines can't just use rubber gloves) but that's incredibly unsafe for experimentation.
  Button navigates to signup page
  (3 votes)
Harshala Raj
Posted 9 years ago. Direct link to Harshala Raj's post “But if graphite is a cond...”
But if graphite is a conductor how can the pencil act as a resistor?
Button navigates to signup pageComment on Harshala Raj's post “But if graphite is a cond...”
(2 votes)
Answer
rosawen2012
Posted 9 years ago. Direct link to rosawen2012's post “why is salt or vinegar im...”
why is salt or vinegar important??
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
- 🚀The knowledge Hunter🔭
  Posted 9 years ago. Direct link to 🚀The knowledge Hunter🔭's post “Perhaps ts because they a...”
  Perhaps ts because they are good conductors of Electricity.
  Comment on 🚀The knowledge Hunter🔭's post “Perhaps ts because they a...”
  (0 votes)
🚹MrBacon🚹
Posted 9 years ago. Direct link to 🚹MrBacon🚹's post “I'm not to sure I underst...”
I'm not to sure I understand this but is a resister an insulator?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
Aiden Swayne
Posted 8 years ago. Direct link to Aiden Swayne's post “What would happen if you ...”
What would happen if you used a pen?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
jc99612510
Posted 9 years ago. Direct link to jc99612510's post “what does the pencil do s...”
what does the pencil do so the compass can move ?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
theonerishi
Posted 11 years ago. Direct link to theonerishi's post “What is the fluid he pour...”
What is the fluid he pours into the cup?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- Flanny
  Posted 10 years ago. Direct link to Flanny's post “Actually, you're both rig...”
  Actually, you're both right: it's hot acid with added salt. The stuff he pours from the cooker is hot vinegar, and he adds a spoonful of salt. Both make the vinegar a better conductor.
  Button navigates to signup page
  (2 votes)
Potato Productions
Posted 7 years ago. Direct link to Potato Productions's post “Won't the rubber band aro...”
Won't the rubber band around the cells affect the outcome?
Button navigates to signup pageButton navigates to signup page
(0 votes)
Answer
lucjustme
Posted 8 years ago. Direct link to lucjustme's post “But why a pencil, not a p...”
But why a pencil, not a pen?
Button navigates to signup pageButton navigates to signup page
(0 votes)
Answer
时若斯/anonymous
Posted 8 years ago. Direct link to 时若斯/anonymous's post “Why did he mark1 at the e...”
Why did he mark1 at the exact point?Why didn't he just mark1 at a random point?
Button navigates to signup pageButton navigates to signup page
(0 votes)
Answer

Video transcript

(coins clank on board) (hot water sizzling into cup) (teaspoon clanking on cup) (pencil scratching on pad)