# What property of molecule structure can be a conductor - electricity?

1. Sep 13, 2011

### oem7110

As we know, plastic is non-conductor, iron metal is conductor, does anyone have any suggestions on what kind of property in term of molecule structure allows electricity to get through?
Thanks in advance for any suggestions

2. Sep 14, 2011

### cragar

Free electrons

3. Sep 14, 2011

### oem7110

I would like to know whether crystal is a conductor or not, does it have any free electrons within structure?
Thanks in advance for any suggestions

4. Sep 14, 2011

### Studiot

This sounds like homework.

Folks here will be happy to help if you provide more detail about what this is for and what you think.

Crystals can be insulators, conductors or semiconductors depending upon the material.

5. Sep 14, 2011

### ZapperZ

Staff Emeritus
Er... measure its resistivity/conductivity as a function of temperature.

You really ought to be a bit more clear on what it is what you want. It appears originally that you are asking for a theoretical band structure calculation. Now, it appears that you want anything, which could be as easily as measuring it!

Zz.

6. Sep 14, 2011

### ZealScience

I've learnt that it has something to do with quantum mechanics because conducting electricity involves electrons with high energy. In metallic material, electrons can easily be energized to conducting electrons and in semi-conductors, it's a bit harder, but with raising temperature, electrons are able to be activated to conduct electricity.

7. Sep 14, 2011

### oem7110

I get no idea on whether Quartiz is conductor, insulator, or semi-conductor. It seems to me that every object has its own fixed vibration, there is the reason how our life count on the vibration of Quartz to measure Time in term of seconds.

Referring to following links, if there is no current provided to Quartz, will Quartz still release a specific range of frequency based on its own vibration in term of any kind of media? such as sound, wave, light, ...

"Piezoelectricity (also called the piezoelectric effect) is the appearance of an electrical potential (a voltage, in other words) across the sides of a crystal when you subject it to mechanical stress (by squeezing it). "

Without applying any external force or current on Quartz's surface, will Quartz keep stable without any kind of vibration? On the other hands, in term of conductor, will Quartz have any free energy in its own molecule structure?
Does anyone have any suggestions?

Thanks in advance for any suggestions

http://www.explainthatstuff.com/quartzclockwatch.html
http://www.explainthatstuff.com/piezoelectricity.html

8. Sep 14, 2011

### ZapperZ

Staff Emeritus
This now makes zero sense. What you just typed here has nothing to do with something being a metal, insulator, or semiconductor. Cesium is an alkali metal, yet Cs atoms are used in atomic clocks! Sand is mostly made up of quarts. Do you think sand is a conductor?

So what does being a conductor, insulator, or semiconductor has anything to do with having a natural frequency?

What is it that you are trying to find out here? If you want to know whether something is a conductor or insulator/semiconductor (the latter really is the same thing), then what's wrong with my suggestion at looking at the resistivity versus temperature behavior?

Zz.

9. Sep 14, 2011

### Naty1

10. Sep 14, 2011

### oem7110

A simple quartz watch costs only a few US dollars.

[PLAIN]http://cdn3.explainthatstuff.com/insidequartzwatch.jpg [Broken]

http://www.explainthatstuff.com/quartzclockwatch.html,
http://www.explainthatstuff.com/piezoelectricity.html,
If you read this article, it makes sense if you know the connection how to make quartz crystal oscillate (vibrate), but I would like to know more about how current makes quartz crystal oscillate in term of its property of quartz crystal.
Does anyone know whether Quartiz crystal is conductor, insulator, or semi-conductor under different situations?
Does anyone have any suggestions on how quartz crystal behaves this way?
Thanks in advance for any suggestions

Inside a quartz clock

In theory, it works like this:
Battery provides current to microchip circuit
Microchip circuit makes quartz crystal (precisely cut and shaped like a tuning fork) oscillate (vibrate) 32768 times per second.
Microchip circuit detects the crystal's oscillations and turns them into regular electric pulses, one per second.
Electric pulses drive miniature electric stepping motor. This converts electrical energy into mechanical power.
Electric stepping motor turns gears.
Gears sweep hands around the clockface to keep time.

Last edited by a moderator: May 5, 2017
11. Sep 14, 2011

### ZapperZ

Staff Emeritus
12. Sep 14, 2011

### oem7110

Referring to the second link, I don't understand the following statement,

"Changing the external force exerted on a piezoelectric material will change the direction of the induced electromotive force produced by the electric field."

Can I reverse the above process by providing current into piezoelectric material and make this material oscillate (vibrate)? in order to understand how Quartz crystal oscillator works as shown below image. However, does anyone have any suggestions on how to provide current into quartz crystals and to make this material oscillate? based on the quartz crystals' insulating properties.

Thanks everyone very much for any suggestions

5 Quartz crystal oscillator.

[PLAIN]http://cdn3.explainthatstuff.com/insidequartzwatch.jpg [Broken]

... A quartz bar can be tiny and oscillate at a relatively low frequency -- 32 kilohertz (KHz) is usually chosen for watches not only for size, but also because the circuits that divide down from the crystal frequency to the few pulses per second for the display need more power for higher frequencies. Power was a big problem for early watches, and the Swiss spent millions trying to bring forward integrated-circuit technology to divide down from the 1 to 2 MHz the more stable disk crystals generate.

Modern quartz watches now use a low-frequency bar or tuning-fork-shaped crystal. Often, these crystals are made from thin sheets of quartz plated like an integrated circuit and etched chemically to shape. The major difference between good and indifferent time keeping is the initial frequency accuracy and the precision of the angle of cut of the quartz sheet with respect to the crystalline axis. The amount of contamination that is allowed to get through the encapsulation to the crystal surface inside the watch can also affect the accuracy ...

What Happens Between the Tick and the Tock?

I also find some video related to Quartz crystal oscillator, but it mentions nothing about how the internal structure of Quartz crystal oscillator vibrate by providing current.

I would like to know more about how quartz bar generates a stable frequency for a watch.
Does anyone have any suggestions?
Thanks everyone very much for any suggestions

Last edited by a moderator: May 5, 2017