Monday, July 30, 2012

Breaking news! Or not....

Well it was brand new in February...

So this afternoon I am teaching for an hour in the Fossils and Dinosaurs camp.  Prepping for this, I was looking at some interesting videos.  I found this Nova program (Ice Age Death Trap) that premiered in February.  I wish I could show the whole thing to the kids (mostly because I want to see all of it), however it's a little long for this age group.  Instead I'm going to show them these three videos.

Video 1 is about Evolution seen in salamanders in California.  It's pretty cool.
Video 2 is about this interesting Prehistoric crocodile found in Tanzania. 
Video 3 is the PBS evening news segment on the Ice Age Death Trap  video.


Monday, July 23, 2012

Fire: Why Blue is hotter than Red and What it Is.

When it comes to understanding fire, the first point I must make is that fire is a chemical reaction.  The physics/chemistry involved in fire is just fascinating. 

Here's what I'm going to cover:
  • How Fire is a chemical reaction.
  • Why Fire produces light and heat.
  • What the different colors in fire mean.

To truly understand how it works we need to understand a few things about atoms.  Atoms are of course made of particles called electrons, protons and neutrons.  Which one plays an important part in chemical reactions?  Electrons have the most influence there.  Protons can play a large part in chemical bonding.

So what's the deal with electrons?  As you know they have a negative charge and they orbit the nucleus of the atom.   What you may not have known is that electrons orbit at specific energy levels.  If an electron moves to a different energy level it must either gain or lose the exact difference in energy levels.
A simple atom in ground state.  The blue is the electron (-) and the purple/pink is the proton (+).

What happens when the energy is gained?  Well the energy must come from somewhere.  "Energy cannot be created nor destroyed" it can only change form. This is why fires can start when it's hot.  If you heat something that is combustible you a giving the electrons energy in the form of heat.  Heat is a form of light, contained in the infra-red spectrum.  Our body interprets infra-red as heat.

This shows hoe our simple atom is excited, and the difference in the energy levels.

All forms of matter prefer being in an non-excited state (the ground state), the state that requires the lowest form of energy it can.  So after an electron is excited it wants to return to the ground state.  Thus the electron gives away the energy it absorbed by releasing it in the form of light.  The light can be all along the spectrum of light.  What states the electron changes between determines the wavelengths of light produced.

This shows how the electron returns to the ground state.
Here we have the spectrum of light, from Radio to Gamma waves, in increasing energy.  Showing how the visible red light is less energetic than visible blue or purple light.

The color of the visible light results from the energy. Blue light is more energetic than red light, which is why a blue fire is hotter than a red fire, it has more energy it is giving off.

This also is true in Astronomy, a blue star is much hotter than a red star. But “what burns twice as bright burns half as long” and maybe the numbers are not exactly true, the idea is, a blue star burns out much faster than a red star.  The hotter a reaction is the more fuel is used up at once. When the fuel is gone the reaction is over.

At night a blue light is much more blinding than a red light because our eyes have adjusted to the dark by dilating or expanding to let more light in.  When we are exposed to that energetic light we receive a lot more energy than our eyes were expecting.  This causes our pupils to shrink very quickly, the combination of all the light and the rapid shrinking causes pain and overwhelms our eyes which is why it is difficult to see afterwards.  When exposed to red light our eyes don't need to shrink much, if at all, so we can stay dark adapted.

To summarize...
  • A chemical reaction resulting in heat and visible light
  • Purple/Blue Fire > Yellow/Red Fire (in energy)

Additional Information
 NASA explains Fire

Need more clarification?  This Richard Feynman video should help!

Let me know if anything was confusing, and always keep asking questions!

Friday, July 20, 2012

Why are Moths attracted to Light?

Most of my research as lead me to this conclusion:  They are not.  Not strictly speaking anyway. 

There are several different thoughts on why they seem to be though.

The first theory (T1) is they get confused by lights.  It seems that nocturnal moths use light for navigation.  Before we lit up the night with light polls, porch lights, and all the other lights we felt compelled to use at night; moths are said to have used the moon for navigation.  Our lights are brighter if they approach it, therefore they use it to navigate by rather than the moon.

Another theory (T2) is the moths are confused by the light because they are trying to get to the darkest spot next to the light.  This is due to "Mach Bands" (in the image below) where a color difference looks strongest at the point of highest contrast.  Meaning that the world looks darkest next to the light.  They are seeking the darkness and the bright light throws them off.  One scientist, Henry Hsiao, observed moths veering away from the light once they got close to it as they rarely actually bump into the light.

For some species of moth we have a third theory (T3) is moths just respond to different wavelengths (or color) of light differently.  This is why you are more likely to see moths around a white light than a yellow light.  One possible explanation of this is their food source.  They often eat the nectar from flowers, similar to butterflies.  Some flowers reflect ultraviolet light.  Ultraviolet light (UV) is a light that we cannot see as it is boarding the visible range.  Some insects like moths and bees can see in the UV range.  This means it is possible that they are approaching the light seeking out food rather than the light itself.

It seems that whatever the cause once they get to the light they are confused.  The reason they are seen sleeping near the light has two theories.
One: They often sleep as a reflex to the brightness mimicking the sun.
Two:  They merely tire themselves out flying around the light so they go to sleep on a near by surface.

A final note on moths: Not all moths are nocturnal.

T1 Links:
Penn State Research
T2 Links:
T3 Links:
How Stuff Works
Penn State Research

Tuesday, July 17, 2012

Quick Update

Hello everyone, I'm just letting you know that I'm alive and working on the fire blog.  I have been exhausted and working a lot lately.

Today I had the glamorous job of cleaning out a fish tank, the same tank I cleaned last week.  It turned green again in a week.  No one expected it to, but we worked very hard on getting the tank completely cleaned.  At one point we took a brief break.  When we (we = me + boss) went back into the animal room the largest fish had jumped out of the bucket we put them in.  He was flopping around on the floor still, so it must have just happened.  I noticed him and put him back before he died.  We then put a cover over the bucket.

Oddly even after days like that I still love what I'm doing.

Tomorrow I will learn how to use the starlab a portable planetarium.  I will be going to a library with my boss and giving a few shows.  I'm starting to get nervous, but also very excited.  I haven't done a show in a little while.

This Saturday I actually have the day off!  This is the only Saturday this month I am free!  Otherwise I will work up to 6 days a week.

I plan on posting a collections of links from recent science articles I like, and hopefully doing this periodically.  I would love to do it once a week, but I'm not sure I can right now.  So I'm going to aim for twice a month posting 10-20 articles I enjoyed over the past two weeks.

Friday, July 6, 2012

Possible Higgs?!

Possible Higgs
I'm speechless....

How to explain this?

Well, in physics we have something called the "Standard Model" which defines all basic particles in the universe as we know it.  The standard model predicted many particles before they were confirmed.  The Higgs particle is the only one that has not been found.

This is one of the main reasons we (mankind) built the Large Hadron Collider (LHC).  The LHC is a particle accelerator, the largest in the world.  The size is important when colliding particles because the particles will have a longer distance to gain more energy before colliding.  All other particle accelerators failed to produce the Higgs particle before the LHC.  Now the LHC may have found it.  As always in science though, more tests are needed to reproduce the results.  But this could really mean a lot to the physics world.

I know this explanation is rather weak right now, and I apologize.  When I have time I will write a thorough post about the Higgs that I hope everyone can understand.

But before I do that one, I still need to work on that fire blog!  I have remembered it.  It is coming.  Expect it soon!

And as always, feel free to contact me with questions.