Παρουσίαση Φυσικής, με υλικό από το Internet. Γουρζής Στάθης - Φυσικός ΓΕΛ Νυδριού Λευκάδος

1. 207 – Παραδείγματα ηλεκτρικών φορτίων και μαγνητισμού
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Γενικό Λύκειο Νυδριού Λευκάδος
Γουρζής Στάθης – Φυσικός

2. Where do charges come from?
Matter is made up of atoms.
+
+
+
–
––
+
–
Proton (positive charge)
neutron (neutral)
electron (negative charge)
atom nucleus

3. Electro-negativity
Relative
electro-negativity
ranking for some
common materials
from electron donating
materials (+, glass) to
electron accepting
materials (-, teflon)
• Glass
• Human Hair
• Nylon
• Silk
• Fur
• Aluminum
• Paper
• Cotton
• Copper
• Rubber
• PVC
• Teflon
+ + + + +
+ + + +
+ + +
+ +
+
-
- -
- - -
- - - -
- - - - -

4. When a balloon rubs a piece of wool...
Where do charges come from?
– electrons are pulled from the
wool to the balloon.
The balloon has more electrons than
usual.
+
+
+
+
+
–
–
–
–
–
The balloon: – charged,
The wool: +charged
wool

10. Transferring Charge
• Electroscopes are instruments that can be
used to detect the presence of a charge.

11. Electricity - electrons moving through a
metal wire.

12. Atomic Absorption

13. Static electricity

14. A Capacitor holds a charge on
its plates.

15. semi-Conductor

16. Integrated circuit

17. There are many sources of electricity such as:
Fossil fuels: coal, oil and wood.

18. Electric Potential Energy
• This spring has more
SPE when it is
compressed
• Likewise, these
charges will have
more potential
energy when they
are pushed closer

19. Electric Potential vs Potential Energy
• Which charge has
more electric
potential?
• Which has more
potential energy?

20. Potential Difference (voltage)
• Why aren’t birds on
power lines
shocked?
• The Potential
Difference between
their feet is zero! (0
voltage)

21. The ion-electron equations can be re-written to
show each step in the reaction:
Mg Mg2+ + 2e
Cu2+ + 2e Cu
Mg2+ + 2e Mg

22. Benjamin Franklin, ca.1750
• Benjamin Franklin – single electrical fluid
– Transfer of electrons
– Positive and negative charges
• Atomic structure

23. Lightning
Lightning occurs when the negatively-charged clouds interact
with the positive charged ground

24. Lightning
Lightning occurs when the negatively-charged clouds interact
with the positive charged ground

25. II. Magnetic fields

26. II. Magnetic fields

30. The Earth is a magnet:
It exerts magnetic
forces and is
surrounded by a
magnetic field that
is strongest near
the
North and South
magnetic poles

31. Magnetism at Different Scales
• Northern Lights
• Magnetic Bacteria