Electroscope Lab
Before the Lab
What did the leaves look like?
 Hanging straight down.
What is making them stay in that position?
 Gravity
So….What did you observe?
What happened to the leaves when you
touched the ball after being rubbed on
the fabric?
 They Spread apart
What happened to the rods when they
were rubbed with the fabric?
 They became either positively or
negatively charged.
Observations….
Why did the leaves spread apart?
 Electrons were transferred off or on the rod.
What happened when you touched the ball of the
electroscope?
 The leaves returned to their natural position
 Electrons transferred to or from the rod to your
finger
to be neutral
 Neutral---equal electrons and protons
 Everything wants to be neutral
Observations cont…
Which piece of fabric added electrons to
the rod?
 Wool---which gave the white rod a
negative charge
Which piece of fabric took electrons away
from the rod?
 Silk---which gave the clear rod a positive
charge
Observations….
How do we know that one piece of fabric made
the rod have a positive charge and the other
have a negative charge?
 Part D of the activity
 The leaves moved closer when the white rod
was close to the ball of the electroscope.
 Started to become Neutral
 If they were both negative/positive the leaves
would have gotten farther apart.
Conclusion
What is the name of this force that pushes the
leaves apart by transfering electrons?
 Electrostatic Force
What can we infer from this lab?
 Opposite charges attract
 Like charges repell
 The charge extends beyond the particle
 This is the 2nd strongest force in the atom
Elements
 Can’t be divided into any simpler
substances.
Atoms
 Smallest particle of an element that still
have all the properties of that element.
Subatomic Particles
 Proton—(+) charge, nucleus
 Neutron—(0) charge, nucleus
 Electron—(-) charge, electron cloud
Elements and Atoms
 90 naturally occurring elements
 20 synthetic elements
What is synthetic?
 Man made