1. Electricity

2. Electricity is the
To understand electricity, we first have to review the structure of matter

3. Atomic Size
Atom = Comes from Greek word for “uncuttable” or “indivisible”
Smallest unit of an element
of that element; Building blocks of matter
Nucleus
Electron Cloud

4. - Basic Atomic Parts + Sub-atomic Particles : Positively charged (+1)
Mass = 1 atomic mass unit (amu)
Found in nucleus of atom
Neutrally charged (0)
Mass = 1 amu
Negatively charged (-1)
Mass ≈ 0 amu (is extremely small)
Found in energy shells outside nucleus of atom + -

5. Basic Atomic Structure:
Center of atom
99% of atomic mass in nucleus
Where the protons and neutrons are found
(Energy Shells)
Regions around nucleus where electrons are found based on how much energy they have
Because electrons are not tightly bound in the nucleus, they can move
N = 3
N = 2
N = 1
Nucleus

6. THINK! What are the charged parts of the atom?
Which part of the atom moves freely around the nucleus?

7. Neutral v. Charged Because electrons can move freely:
When an atom has a balanced number of positive (+) protons and negative (-) electrons, then the object is
If more (+) , then positively charged
If more (-) , then negatively charged
Overall, objects that are have an unequal number of protons and electrons

8. THINK! What makes an object positively charged?
What makes an object negatively charged?
What makes an object neutral?

9. When electrons move (like when you rub a balloon on your hair or wool), the moves too!
In the balloon case, your hair or wool is left with
a and the balloon now has extra electrons so it has a charge
Your hair or wool and the balloon “stick together”
positive-negative/ neutral-negative

10. What if I charge a second balloon by rubbing it against hair or wool…

11. The second balloon also has a negative charge and it pushes away from the first balloon

12. Conductors v. Insulators
are materials that electrons can freely flow through
Conductors distribute electrons throughout an object
Ex. Metals, Water, YOU…
are materials that electrons can’t easily move through
In insulators electrons get “stuck” in one place
Dry air, wood, glass, rubber

13. THINK!
Are electrical conductors/insulators the same or different from heat conductors/insulators?
Give an example of a good conductor for electricity and a poor conductor of electricity

14. Ways of Charging When objects slide past each other
One materials gains electrons/ one loses electrons
Balloon on head, rubbing your feet on the floor and getting shocked by a doorknob

15. A charged object comes in contact with a neutral object
The charged object “gives” its charge to the neutral object
Ex. Touching a charged balloon to neutral bits of paper

16. Bringing a charged object really close to a neutral object BUT not touching it
Overall net charge of neutral object stays zero

17. Exit Ticket

18. Which of the following particles has a negative charge?
Proton
Neutron
Electron
Atom

19. Which of the following is not a good conductor of electricity?
A. Aluminum
B. Glass
C. Silver
D. Copper

20. A conductor differs from an insulator in that a conductor….
Has an excess of protons
Has an excess of electrons
Can become charged and an insulator cannot
None of the above

21. Electrical forces ____.
a. can cause objects to only attract each other
b. can cause objects to only repel each other
c. can cause objects to attract or repel each other
d. have no affect on objects