science941key

actorrattleUrban and Civil

Nov 15, 2013 (3 years and 7 months ago)

61 views

Assignment

1.

Across

1.

nonmetal

10. electron

11. charged particles

16. metals

17. atom

18. unbalanced

19. coulomb


Down

2.

superconductors

3.

electrostatic

4.

charged

5.

conductors

6.

discharge

7.

static

8.

unlike

9.

neutralized

12. grounding

13. proton

14. insulators

15. like



2
.

1.

The balloon gains
negative

charges (electrons). There is an electrostatic buildup.

2.

When the balloon gets rubbed on the sweater, it becomes negatively charged (due
to the physical properties of rubber and wool). Then when the balloon is against
the wall
,
positive charges will attract the negatively charged balloon

since
opposite charges will be attracted towards each other.

3.

The balloons
move apart
( repel)
as they receive similar charges.

4.

The more the charge the
farther apart
the balloons move.

5.

Lightnin
g is an
exchange of charges
. The clouds become negatively charged
relative to the ground or other clouds. Since opposite charges attract, a lightning
bolt will appear as charges are exchanged between the cloud and the ground.


3.
Conductors, Insulators,

and In
-
between


Insulators

are materials that do not allow charges to move freely on or through them.
(Most non
-
metals) Hold their electrons tightly.


Conductors

are materials that allow charges to move freely. (Most metals) Hold
their electron
s loosely.


Semiconductors

are materials with higher conductivity than insulators but with lower
conductivity than metals. Conductivity is increased by implanting foreign atoms into
pure material.


Superconductors

are materials that offer little
, if any, resistance to the flow of
charges. Usually metal alloys and ceramics. Some materials become superconductors
when subjected to extremely low temperatures.




Neutralizing Unbalanced Charges


The sparks that result from static cling a
re an electric discharge as the accumulated
charge on the clothing was neutralized.
Connecting an object to Earth with a conducting
wire is called grounding the object and is an easy way to neutralize conductive materials.


Non
-
conductors, or insulato
rs, usually must be neutralized with ionization.



Preventing Electrostatic Buildup


Antistatic sprays, coatings, special antistatic packaging, grounding straps.