2. Our Questions...
❖ Why are some minerals piezoelectric, while others are
not?
❖ What are the everyday applications of piezoelectricity?
3. What is piezoelectricity?
❖ When certain minerals are exposed to a short burst of
high stress, they can produce a temporary electric
charge. This is called piezoelectricity. The Greek word
"piezo" means "push" or "squeeze" so, piezoelectricity
literally means electricity derived from pushing. Any
mineral with this property is referred to as a piezoelectric
crystal (or p.c for short).
4. How does piezoelectricity
work?
❖ Imagine the p.c as a battery, with a positively charged
end and negatively charged end. In a resting state, these
charges cannot be noticed. However, if the crystal is
compacted, current can flow, and the charged is
released.
❖ These positive and negative charges are normally
balanced out, so you can't noticed then. Any compaction
(or stretching) of the crystal can mess up the balance,
resulting in a shock.
5. What materials are
piezoelectric?
❖ Many materials, both natural and
synthetic are piezoelectric,
including:
- Quartz
-Sucrose (sugar)
-Tendon & bone
-Dentin & enamel
-Silk
-DNA
6. Why are some materials piezoelectric, while
others are not?
❖ It all has to do with the mineral's structure. A mineral with
a symmetrical structure will not be piezoelectric because
the electrical charges are always balanced. If the mineral
structure is not symmetrical, it can be deforming,
resulting in electric charge flowing through the crystal, so
this mineral is piezoelectric.
7. Applications
❖ Use of piezoelectricity can be found in:
❖ Quartz watches, piezoelectric
crystals are inside to help keep time
❖ Microphones, used to translate
sound energy into electrical signals
❖ Record players, p.c are used to
"read" the record
❖ Cigarette/barbecue lighters, used to
spark the gases to light the flame
❖ Igniters of many grills and cook tops
8. Piezoelectricity in Lighters
❖ Barbecue lighters use naturally
occurring quartz as the igniter
because it is piezoelectric .
When you pull the trigger on a
lighter, that clicking noise you
hear is actually the crystal being
compacted. The spark is
creates ignites the gas to light
the flame.
11. Our Topics
❖ Our initial question involved finding
out what minerals are in the
superfruits that are supposed to
make drinks like Bai5 so healthy.
❖ We then moved on to what minerals
are present in our iPhones.
❖ Our topic changed once again to
piezoelectric minerals and what they
are.
❖ Half-way through our research, we
expanded our question to include
applications of piezoelectricity.
12. Obstacles faced
❖ We initially faced many obstacles, which is why we
switched our topic so many times. These first few obstacles
included other people researching similar topics and lack of
readily available information. We realized that it would be
better to switch to a new topic that has a lot of information
and that other people are not researching.
❖ While researching our final topic, we still had a few issues
with lack of available information. To fix this, we would
broaden the range of our question so that we had more
resources to our disposal.
Notas do Editor
Slide 2
Chloe: We have a two part question
Ben reads first question
Chloe reads second question
