What Does a Lightning Rod Do?

Okay, I lied.  I said previously that I was done discussing thunder and lightning on this blog, but another misconception recently popped up and I can't NOT talk about it.  :-)  The misconception focuses on lightning rods.  We've all seen lightning rods, but most of us have a couple of misconceptions regarding lightning rods.  If you ask someone what the purpose of a lightning rod is, you will most likely hear them say that the purpose is to attract lightning.  But is that really what they do?  Yes and no.

A lightning rod doesn't really attract lightning.  It creates a path of least resistance from the top of a building down to the bottom.  A lighting rod is nothing more than a long stick of metal that creates a conductive path for charge to travel.  Lightning striking a lighting rod travels safely down the building to the ground, decreasing risk of fire and computer damage to the building.  The main purpose of a lightning rod, however, is NOT to attract the lightning.  The main purpose is to slowly leak charge down to the ground to avoid a lightning strike.  In some cases too much charge still builds up and there is a strike.  In the case of a strike, the charge is safely transferred to the ground.  

Avoiding the strike to begin with is the best option, thus the main purpose of that lightning rod is to leak charge, not attract the lightning.

Building a Rube Goldberg Machine

Facing a rainy weekend?  Kids bored?  Are you bored and looking for a cheap activity to do with your kids?  Then build a Rube Goldberg Machine.  A Rube Goldberg Machine is a device that you build out of any random pieces that is designed to complete a very easy task in a very complicated way.  The best analogy to a Rube Goldberg Machine is the Mouse Trap board game.

The goal in Mouse Trap is to drop the cage on the mouse, but it's done in a many step, complicated process.  For the Rube Goldberg Machine you decide what the task is (e.g. turning on a lamp, popping a balloon, etc.) and then build a machine that takes many steps to complete the process.

There's really no need to buy any supplies.  Just find random things in your house to complete your steps.  Want to make the task more challenging?  Add more steps!  I do this as a project in my physics classes for high school classes.  Here a few pictures of Rube Goldberg Machines they designed.

In the above Rube Goldberg Machine, the goal is to ring the bell on the right.  A marble is dropped through a partial pop bottle, down a couple of ramps, it turns a ferris wheel, tips a ramp, and pulls on a string that rings the bell.  

The options for your Rube Goldberg Machine are limitless.  Use your imagination as a parent, and let your kids use their imagination to decide on and build steps to complete a random task.  

Annular Solar Eclipse - Tuesday, April 29, 2014

Fresh off all the talk of the April 15, 2014 lunar eclipse seen in the western hemisphere comes the April 29, 2014 annular solar eclipse.  What is an annular solar eclipse?

First, a solar eclipse occurs when the Moon is positioned directly in front of the Sun, casting a shadow on the Earth.  The Moon is smaller than the Earth, so the Moon's shadow cast on the Earth is much smaller than the Earth's shadow cast on the Moon during a lunar eclipse.  Thus solar eclipses have a very short duration and you must be at a specific location on Earth to see the eclipse.

Second, the Moon's orbit around the Earth is slightly elliptical.  Thus the Moon is a bit farther away from the Earth at times.  When it's a bit farther away at the same time the Moon is aligned with the Sun and the Earth, the size of the Moon in the sky is slightly smaller than the size of the Sun as seen on the sky.  Thus the Moon doesn't block all of the Sun.  The Moon blocks the interior disk of the Sun but not the outer ring of the Sun's disk.  This is an annular eclipse.

Tomorrow, April 29, 2014 at just a couple of minutes before 6 AM EDT, an annular solar eclipse is observable from parts of Earth.  If you live in Antarctica or the eastern part of Australia, you'll be in position to see this eclipse.  No such luck for those elsewhere in the world.

This Blog's History: Sweaty Feet

This Friday in This Blog's History I bring back to you the sweaty feet post.  How much do your feet sweat in a single day?  I'm guessing you'll be very surprised to learn the truth.  Check out the original post below.

How Much Do Your Feet Sweat?

Father Daughter Dances

This is a call on all dads out there to take time out of your schedule to participate in any father daughter dance opportunities that arise.  Many times elementary schools will set up an annual father daughter dance.  Do everything you can to attend!  You only have so many opportunities to dance with your little girl before she becomes a big girl and is off doing her own thing with her friends.

When you attend a father daughter dance, be an active participant.  Set some expectations with your daughter.  If your daughter is one who wants to run off with her friends, then let her know that you expect her to return and dance with you for any and all slow dances.  If your daughter, like mine, isn't one to wander off with her friends, then make sure you're paying attention to her.  Talk with her, dance with her, stay off your phone, and look genuinely interested!  I get that a dance may not be the funnest thing in the world for a dad, but you can make it fun by actively participating with your daughter.  I'm not saying you should be in the middle of the dance floor shaking it to Baby Got Back.  But don't hide off in a corner with your arms folded or playing on your phone for the full two hours.

If you play an active role in your daughter's life now, while she's young, she'll let you play an active role in her life when she's a snotty teenager!  :-)

Summer = Sunscreen Time

Summer is quickly approaching which means it is time to stock up on sunscreen for you and your kids.  I've posted about sunscreen before, most recently here.  There are new regulations on SPF numbers since studies show that really high SPF numbers are no better than SPF 50.  Thus all sunscreens are now supposed to be labeled SPF 50+ (not SPF 85 or any number higher than 50).

SPF Regulations

I realize it can be annoying and oftentimes frustrating to lather your kids with sunscreen whenever they go outside.  However, consider the long term alternative.  A sunburn itself heals and your skin returns to its normal color, but there are long term affects due to deep tissue damage.  This is where your chance of skin cancer later in life greatly increases.

Here is a great source for stats and info on skin cancers.

Skin Cancer Facts

All it takes is one serious sunburn as a child to greatly increase your chance of skin cancer later in life.  As an adult you can protect yourself, but your kids need your help to protect them.  Do you parental duty and lather your kids up with sunscreen, even if they kick and scream while you do it.  :-)

Marker Hands

As mentioned in a previous post, I took my 7 year old daughter to work with me for 2 days over her Spring Break.  One would think that different schools in the same community would align their Spring Breaks with each other, but no.  Thus my wife and I had to work while my daughter was out of school.  Oh well.  My 7 year old packed bag of things to do while I taught classes.  On the first day we arrived at the office around 7:45 AM.  I told her I had to do a bit of work and prep before my first class of the day.  No problem, as she pulled out a coloring book and some blank paper and worked on drawing some pictures.

Less than 10 minutes later she comes over to me and says she needs to wash her hands.  Just as I start to ask why she needs to wash her hands, I look over and see this:

Ok, I have a Ph.D. in astrophysics, and yet I do NOT understand how it's possible to get one's hands this colored after just 10 minutes of drawing!!!  How...is...this...possible!?!?!?!  LOL!

Air Cannon

At a recent Science Day my family attended, there was a table with air cannons.

An air cannon, as shown above, is a tube like device with a plastic wrap at the end.  There's a knob on this plastic wrap that one pulls back as tight as possibly.  When the knob is released, the plastic wrap is pushed forward, and shoves a volume of air out the tube in a column.  At the Science Day, cups where set up in a pyramid pattern to allow for a bit of target practice with the air cannon.  My daughters needed some help pulling the knob back tight, but once they got the hang of it, they were all about knocking those cups down.

You can get one yourself fairly easily.  They are cheap to buy.  You can get several off of Amazon.com for around $15 - 20

Air Zookas

There are several websites with instructions on how to build your own.  Here's one:

Build an Airzooka

Building one is a great activity for you and your child, but even if you buy one already built, you've got an afternoon of fun with your kid(s)!

This Blog's History: Colder than Mars?

This Friday in This Blog's History I bring back to you the colder than Mars misconception.  This was mentioned many times in the media when describing the cold weather experienced by much of the midwest and eastern United States in January and February 2014.  Although this is technically true, it leads to a very big misconception regarding temperature on Earth and Mars.  For full details, read the original post, linked below.

Colder Than Mars Misconception

Take Your Daughter to Work Day

The official "Take Your Daughter to Work Day" this year is April 24.  However, you don't have to wait until April 24 to take your daughter to work and share your day with her.  This is easier for some jobs than others, but if there's any way possible to take your daughter to work, even if it's just an hour or two, do it.  This is especially true for dads.  Open up your lives to your daughters and help them understand what you do every day when you're not home.

I had the opportunity in March to take my 7 year old to work with me for a couple of days over her Spring Break.  I'm a teacher and my spring break did not align with hers, so while she was on Spring Break, both my wife and I had to work.  For 3 of the 5 Spring Break days we had to take her with us to work.  I took her for 2 days and my wife took her for 1.

My 7 year old packed a bag of things to bring and do while I taught classes, but she sat in the classroom with the other students.  She said she enjoyed it, and although I can tell she was getting a bit bored by the end of the third day, coming to work with me on occasion is a great experience for her and a great bonding experience for her and her dad (that's me!!!)  If you have an opportunity to take your daughter to work, do it!

Lunar Eclipse Viewing

This past Tuesday morning there was a total lunar eclipse observable from North America.  I set my alarm for 2:30 AM and went out to check the Moon before waking up my kids.  It was overcast out, so the Moon was obscured by the clouds.  After a couple of minutes the Moon appeared in a partial eclipse phase.  It was still 30 minutes from totality so it looked just like a crescent Moon would look, white in color.  15 seconds later the Moon was covered by clouds again.  I went back inside until 3:05 AM and headed back out to see if I could see the Moon during totality.  Unfortunately the Moon was hidden by clouds.  So I let the kids sleep.  No total eclipse for me or my kids.  Boo!!!  The next lunar eclipse is this October.  I'll try again then.

Science Day!!!

This past week my wife and I took our two daughters to a Science Day sponsored by a local college.  It turned out to be an awesome morning for all of us.  The Science Day was held at a building on the fairgrounds and the entire building was filled with tables of science demos/experiments, including several demos set up outside.  We went from table to table and had a blast.  There were demos dealing with density, magnetic fields, water, sand, air, balloons, rockets, etc.  Everyone received a passport book to have each demo table stamped in a book to keep track of what was done and what still needed to be done.

Unfortunately we had a few other things going on that day and didn't get a chance to see every table, but we marked off about 2/3 of them in the passport book.  We were able to take several of the demos home with us and we received a book of science demos/experiments to do on our own at home!  How cool!!!  Over the next 2 months I'll post several of the demos to this blog.  Some my kids and I have done before, but others are new!

I'm not sure who was more excited at the Science Day:  me or my kids!  We all had a blast, that's for sure!

Lunar Eclipse Reminder: April 15, 2014

A reminder that there's a great opportunity to see a total lunar eclipse (for the U.S. and most of the western hemisphere) early tomorrow morning. From an earlier post on this:

"The April 15 eclipse begins at about 2 AM EDT.  This is when the Earth's shadow just starts to creep across the surface of the Moon.  Totality begins at about 3 AM EDT and ends at about 4:30 AM EDT.  The Earth's shadow  moves off the Moon at approximately 5:30 AM EDT."

Tuesday, April 15 is a school day for my 7 year old and a long work day for me, but I've decided I'm not passing up this opportunity.  I'm going to set the alarm and wake my kids up and take them outside (assuming it's not cloudy).  Yeah, it might be a rough day, but the opportunity to share an amazing astronomical observing event with my daughters is priceless.  It's a moment they'll never forget!  And neither will I!

Hopefully I'll have a post soon about our experience.  If not, it means it was cloudy and I went back to bed disappointed!

This Blog's History: Seeing Your Own Breath

This Friday in This Blog's History I bring back a science misconception regarding the sight of one's own breath.

Seeing Your Own Breath

As kids we often think seeing our breath means we have smoke coming out of our lungs.  Cool if we were dragons, not cool as humans!

Get the truth of seeing your breath by visiting the original link above.

The Egg Drop Winners

Someone recently posted to one of my previous egg drop posts (check here, here, and here) that I should state which ships "won".  I have 8+ years of ship pictures and can't recall the specific ships that did the best, but the ships that tend to do better than others are designed similar to these below.

The above ships both have the design of suspending the egg somewhere in the middle of the ship, away from touching the ship walls.  When the structure strikes the ground, regardless of side, the ships are designed such that the egg does not make contact with the ground.  This typically prevents the egg from easily breaking.  

I've seen other ship designs do equally well and I've seen ships with suspended eggs do poorly, but typically the suspended egg ships survive longer than others.  

Pre-Order Life to Her Years

A little over a year ago I ran across the Life to Her Years blog.  It's a fantastic parenting blog put together by Michael Mitchell.  I highly encourage you to check it out.  Most entries involve a child/parent picture with a short sentence or two.  They are great reminders to appreciate the little moments in life with your kids.

Mr. Mitchell has turned his blog into a new book that is to be released very soon.  I'm helping him, as part of a large team, to get word out on his book.  To pre-order the book, go to Life Lessons for Dad: Tea Parties, Tutus and All Things Pink.

I've had a chance to read through the book and it is a great book for all dads and comes at a very reasonable price (under $10!!!).  This would be a great Father's Day gifts for all dads out there! 

Lightning Safety

One more post on lightning and then I think I'll move on to another topic...maybe.  :-)  It's important to teach your kids lightning storm safety.  You can't always protect yourself against a lightning strike, but there are things you can do to decrease your chances of getting struck.  For starters, a lightning storm doesn't have to be very close to you to cause damage.  You can be struck by lightning from a storm up to 10 miles from your location.  Thus it is always important to seek shelter when you see lightning present.

The best place to go is a house, away from windows and any metal that might be in contact with the outside walls.  There are a few cases of people receiving severe shocks holding onto a sink faucet inside a home, since the pipes in the home were metal.

It's okay to be in your car.  A car has a metal casing and rubber tires.  Don't exit your car, but inside your car you are safe.

Stay away from water, trees, and open fields.  Under a tree may protect you from rain, but a bolt of lightning can strike a tree, travel down a tree, and then produce a side flash to you which can be just as damaging as the original lightning strike.

If you are stuck in an open field, there are a few things you can do to protect yourself.  One is to squat down low to the ground.  Lightning strikes more commonly occur with taller objects.  Decreasing your height can help.  Also keep your feet together, touching.  Separating your feet creates a path through your body that current can enter and then exit.  Keeping your feet together reduces the chance of this.  None of this eliminates the possibility of being struck, but it does reduce the chances.

If you're in water, get out!

Here's an excellent source on lightning safety.

Thunder and Lightning Safety 

Moral of this?  Knowledge of science may one day save your life!  :-)

Is it Safe to Touch Someone Struck by Lightning?

Apparently I'm on a big lightning kick, given my recent posts on lightning.  Here's another.  Is it safe to touch someone struck by lightning?  There's a common misconception that you should never touch someone struck by lightning because you'll also be severely injured.  This is completely false.  If someone is struck by a bolt of lightning and in need of medical attention, by all means go to them and help.

It's true that if someone is touching a downed power line that you should stay away.  In this case they may still have current from the power line traveling through their body and you touching that person can cause that current to jump to you.  However, when struck by a bolt of lightning, the current is not continuous.  It travels through the person's body down to the ground in a split second.  After the strike there is no more current traveling through the person's body and the person is perfectly safe to touch and help.

This is a good lesson for your kid's that they should have no fear helping someone in need out.  Physics tells us there is no danger in this situation.  Again, be sure to tell you kids never to touch someone holding or in contact with a power line or any other electrical device that has sent a current to his/her body.  That IS dangerous.

This Blog's History: What Does NASA Stand For?

This Friday in this Blog's history I bring back to you the post on NASA's meaning.

What Does NASA Stand For?

Ask the average person what NASA stands for and he/she will almost always get it wrong.  The 'N' is easy.  National.  Most people get the 'S'.  Space.  The 'As' are where people get messed up.  It's very common for someone to say one of the 'As' stands for astronomy.  Good guess, but nope.

So what does it stand for?  I guess you'll have to check out the original post.  :-)

Odds of Surviving a Lightning Strike?

A year and a half ago I first posted on a very common misconception regarding thunder and lightning.  It's a big misconception that the number of seconds between the lightning and thunder is equal to the distance in miles to the strike.  The strike is actually 5 times closer!  For full details read the original post here:

Thunder/Lightning Distance Misconception

There's also another misconception that a human struck by lightning almost always dies.  This is simply not the case.  I'm not advocating that you go out and get struck by lightning, but your odds of surviving a lightning strike is much greater than 0%.  Here's an excellent page on lightning strike facts.

Lightning Strike Facts

Your odds of surviving a lightning strike are actually quite high.  Only approximately 10% of people struck by lightning die from the lightning strike.  Granted, many of these people are seriously injured and up to 70% suffer long term effects from the strike, but 90% live to tell the story.

That 90% survival rate is quite impressive in my opinion.  A bolt of lightning carries 100 million volts, compared to a 120 volts from a typical wall outlet in the U.S.  In addition, lightning super-heats the surrounding air to 50,000 degrees Fahrenheit.  Given those numbers it's amazing that anyone survives a lightning strike, let alone 90%!

So what are your odds of getting struck by lightning?  Given an 80 year lifetime, your odds are 1 in 3,000 at some point in your life.  Much higher than one might expect, but still very unlikely.  

Blog Stats Update

This blog had its best month ever in March 2014.  There were 5,587 visitors in March with an average of 180 visitors per day.  As you can see from the graph below, the general trend of visitors is upward!  Can't complain about that.

Overall, this blog just moved past 70,000 visitors since its inception in May 2012.  Let's keep it up!

The Question that All Parents Must Face

The other day in the car my 6 year old asked me the question that all parents face.  It's one of those questions that shapes the rest of your child's life!  No, it's not the sex question.  No, it's not the where do babies come from question.  It's the why is Pluto not a planet question!!!

It's too bad there wasn't a camera on me when she asked this question.  My face lit up in a smile and as an astrophysicist with a Ph.D., I had an answer prepared.  So why is Pluto NOT a planet?  Well, it boils down to 3 things.  There are three criteria that must be met for an object to be classified as a planet.

1.  The object must orbit the Sun.  Pluto satisfies this requirement.

2.  The object must have enough mass such that it is spherical in shape.  Pluto satisfies this requirement.

3.  The object must have "cleared" its neighborhood of debris.  This is where Pluto fails.

Larger objects have enough mass to clear their area of other debris.  They may have moons and asteroids, but this is a result of large enough gravitational forces to strongly influence their orbits.  Pluto does not do this.  There are other Pluto-like objects near Pluto and Pluto has neither pushed them away nor gravitationally attracted them.  Thus Pluto is not a planet.  Instead, it fits into a new category of objects called dwarf-planets.