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Brian,
PA | Moon
Have you ever noticed that the moon looks different at the end of
every week andat the end of the month it starts another cycle?
Jordyn,
9, AK | Looks for
rocks in Alaska
Dear dragonflytv, I have a rock collection.I have looked at them
very carefuly and I found some prety cool things.Like rocks are
made from tiny minnarls. Well I got to now. Bye
Josh,
5, WY | Looks for
rocks in Wyoming
I like Dragonfly t.v. I like experiments like ballancing a ball
on a hair dryer. I like looking for rocks like crystals, and fosils
and "keeper" rocks. I live in Wyo. next to the Rocky-
Montains. There are lots of different rocks, and there are dinosour
tracks in Wyo. too.! Where I live we find lots of shell fossils
and rock wood. I want to do an experiment with my rocks. Do you
have an idea of an experiment I can do with rocks?
Madalyn, 6, NJ | Hard
rocks
Rocks are hard.
Rachel, 40, OR | Found
a footprint
I found a rock that looks like it has a disanour foot print in it.
Where would I go to find out what it is? I found it in a cave.
DragonflyTV
| Found a footprint
response
You might want to check out these great Web sites. The John
Day Fossil Beds National Monument in John Day, Oregon, the Museum
of Natural History at the University of Oregon in Eugene. Lastly,
the Oregon
Museum of Science and Industry, in Portland.
Theresa, 40, CA | Get
a copy
How do I get a copy of one of your shows?
DragonflyTV
| Get a Video Response
Tapes are not available for sale at this time. Teachers have off-air
recording rights for one year from the date of broadcast.
Daniel, 5, OR | Rocks
that float
There is one kind of rock that floats and its called pumic. It gets
exploded out of a volcano. We find it here in Oregon and I think
maybe in Hawaii too.
Katie, 8, MI | Has a collection
I have a rock collection at home and I have tons of rocks. One of
them is a fossil. It has a shell in it and I was amazed to find
out that it was millions of years old on todays episode. I definitly
think rocks rule!
Chris, 10 | Age of
rock?
How can you tell how old a rock is?
DragonflyTV
| Age of rock response
Here's a response from Dr. Chris Paola, Geologist from the
University of Minnesota: Wouldn't it be great if you could tell
how old a rock is just by looking at it? Unfortunately, though there
are lots of ways of telling the age of a rock (we call that 'dating'
the rock, but it doesn't mean we have to buy it flowers!), they
all involve careful analysis of the rock and its contents. The
main way we measure the age of a rock is by the decay of radioactive
elements that occur in many types of rocks. A radioactive
element (or, more properly, a radioactive 'isotope' -- an isotope
is a particular form of a given element) decays -- changes form
-- into a different isotope or element at a known rate. Each radioactive
isotope (e.g. uranium-238) has its own decay rate, and we can measure
these very accurately. We also know that these decay rates are independent
of time, temperature, pressure, etc. So the radioactive isotopes
in a rock form a kind of clock: the longer it's been since the rock
formed, the more the isotopes have decayed. By
measuring how much the radioactive isotopes in a rock have decayed,
we can measure how long it's been since the rock formed.
If the rock has fossils, you can also use those to tell the age
of the rock. By dating the evolution of life with our 'isotope clocks',
we can infer the age of the rock from its fossils.
Jae,
8, FL | Likes rocks
Rocks rule!
Sam, 10, OH | Friend
collects rocks
My
friend jessica would always collect rocks, if she saw them in the
streets or just laying around but i am not really sure if she knows
anything about them.
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