Electron Flow Through Matter
There are different degrees to which electrons can flow through matter. Make a prediction regarding the flow of electrons for the following pieces of matter.
In the table under 'Prediction' Write.. YES ­ if you think it will allow electrons to flow through
SOMEWHAT ­ if you think it will allow some flow of electrons
NO ­ if you think it will not allow electrons to flow through
Matter Prediction Observation Matter Pure water Rock Pickle
Rubber eraser Dry Pasta Paperclip Plastic rod Graphite Hair gel Cooking oil Spoon Ceramic Prediction Observation Now, observe the conductivity meter and record your observations using the same three words.
Conductors
• A material through which electrons __________ flow easily between atoms
• Hold electrons _______________
• 3 examples:
Insulators
• A material through which electrons __________flow easily between atoms
• Hold electrons more _____________ than conductors
• 3 examples: Resistors
somewhat
• A material through which electrons can flow ____________ between atoms
more
less
• Holds electrons _________ tightly than conductors but ______ than insulators
• 3 examples:
can
cannot
loosely
tightly
Consider the insulators in the demonstration: Could electrons ever pass through them? __________________
Can you think of an example of when this might occur? ____________ _________________________________________________________
The Electrostatic Series
• Within the category of insulators some materials have a greater ability to obtain electrons than materials. See table.
Ex.
Charging by Friction
When two materials with different abilities to obtain electrons are rubbed together:
1) The more loosely held electrons from one material are removed and deposited on to the other different material
2) This results in both materials having a charge
Material that gains electrons àbecomes __________________ charged.
Material that loses electronsà becomes____________________ charged.
Using the __________________________, we can predict the charge of each object.
Ex. A balloon rubbed on a wool sweater (click here)
Before being rubbed ­ we assume both objects are _______________ ­ meaning the same number of _______________
and _________________. The _________________ has a stronger hold on electrons.
Before: Draw a neutral balloon and sweater
neutral
rubber
neutral
wool
During: Draw the balloon and sweater next to each other, show the movement of electrons with arrows.
After: Draw the balloon and sweater with proper charges
Homework­ Complete the Electrostatic Series Worksheet
Electrostatic Series Homework­ Answers
1) Neutral Balloon with 5 negative charges
2) Positive balloon and negative balloon
positively negatively
charged charged
hair­weak hold on e­
wool ­strong hold on e­
See arrows in question 3 showing movement of electrons
7) Ben Franklin
a) rubbed a glass rod on kitten #1 (Willow)
b) rubbed an amber rod on kitten #2 (Eddie)
•
•
•
•
•
•
•
•
•
•
Glass
Human Hair
Nylon
Wool
Cat fur
Silk
Paper
Cotton
Wood
Amber