Water Conductivity

We've all been told to avoid standing under trees during lightning storm over risk of getting struck by lightning.  The same applies to standing in water.  Whenever a storm approaches, outdoor swimming pools are cleared for the safety of swimmers.

Don't get me wrong, it is very important to avoid water during a lightning storm, but unfortunately this leads to the misconception that water is an excellent conductor of electricity.  The misconception states that lightning striking water will easy conduct through the water to anyone standing in the water and thus electrocuting them.

Although you are very likely to be electrocuted if lightning strikes water you are standing in, it's not the water itself that increases conductivity.  Water is a very poor conductor of electricity.  The catch however, is the difference between pure and impure water.  Pure water is a very poor conductor of electricity but we rarely come across pure water.  Most water is filled with minerals (e.g salt).  The ionic compounds from these minerals are what conduct electricity and make it dangerous to mix water and electricity.  Even tiny amounts of these compounds greatly increases the conductivity.  Thus fresh water which we normally think of as unsalted, will easily conduct electricity through ions.    

Sneaky Conversation

My 7 year old has reached the age where she is constantly asking why about everything.  This is a good thing!  It shows she's interested in knowing the answers to her questions and isn't willing to settle for a simple one or two word response.

Lately she has the tendency to notice when Mommy and Daddy are talking and sneak up on us.  We'll see her peaking around the corner listening to our conversation.  When noticed, she smiles and giggles.  The other day we were sitting on the couch when she comes in, squeezes herself between us on the couch and says "watcha talking about" with a big smile on her face.

It's too hard to get mad at her for interrupting our adult conversation given the big smile on her face and her desire to know more.  It's natural for a child to want to do this.  I remember doing this all the time as a kid.  I usually didn't butt right in, but I'd hang around a corner and listen in to conversations between my parents.  Was I being snoopy?  I suppose so, but I didn't think so at the time.  I just wanted to learn more about my surroundings.

So although my daughter's constant asking of questions and butting in during adult conversations can be annoying, it's important my wife and I respect our daughter's wish to learn more.  The last thing we want to do is to suppress her desire to learn!

This Blog's History: Ice Fishing for Ice

For this Friday in This Blog's History I bring back to you a cool science experiment you can easily do in your kitchen with commonly owned materials.  Plus you don't have to go outside in the cold to go ice fishing!  This experiment teaches kids how to literally fish for ice...with a string!  It's a cool experiment your kids will love, so check out the original post below for full details.

Ice Fishing for Ice

End of the Messenger Mission

You may have read this in the news, but if you haven't, a very important NASA space mission is soon ending.  Messenger is a mission to further study Mercury.  Mercury was last visited by a spacecraft (Mariner X) in the 1970's.  Mariner X, however, did not fully map the surface of Mercury and it left open many questions regarding Mercury's magnetic field.  

The Messenger spacecraft launched in 2004, and entered orbit in 2011.  Messenger mapped the entire surface of Mercury at high detail giving us awesome pictures such as this:

The detail in this image is simply amazing!  

In addition to studying Mercury, Messenger has also studied energy flows from the Sun.  Alas, all good things must come to an end and that holds true for Messenger.  The official end of the mission occurs very soon with a controlled descent and crash into the surface of Mercury.  Will another 30-40 year elapse before we visit Mercury again?  Only time will tell.  For more information on the Messenger mission, check out:

Messenger - Johns Hopkins

Messenger - NASA

Blowing on Hot Food

We were all likely told as kids to blow on hot food to cool it down and any parent reading this, including me, has likely told their kids to blow on hot food to cool it down.  What we haven't done, is consider WHY blowing on food cools it down.  For hot food to cool, energy (heat) must transfer from the food to the surroundings (air, plate, glass, etc.).  How does blowing on food transfer energy out of the food to the surroundings?

The air you blow across hot food is at a lower temperature than the hot food itself.  At first glance, it may seem that blowing this cooler air across the hot food is what cools the food.  Not exactly.  When you see steam rising from your food, this is the evaporation of water molecules into a gas that then quickly cool to form tiny water droplets in the air.  The steam you see is the collection of tiny water droplets.  As these molecules escape, your food cools down.  However, many of this molecules 'fall' back into or onto the hot food.  The food is slowly cooling as not all molecules return to the food, but the process can take awhile.

To cool your hot food more quickly, you blow across the food to move these molecules (steam) out of the way such that they don't return to the food.  If the molecules don't return to the food, energy is not added back into the food, thus the food cools down more quickly.  

Common sense and daily experiences tell us that blowing on food cools it down more quickly.  Now you know the WHY behind it.  :-)

Static Electricity and Balloons

I recently took my 4 year old to a birthday party for one of her pre-school friends.  The party took place on an indoor soccer field made of artificial turf.  The turf has fake grass blades embedded in a layer of tiny rubber granules.  One of the party activities involved balloons and it was quickly observed that the rubber granules stuck very easily to the balloons, as shown below.

Tap the balloon a few times and the rubber granules fall off.  So what's going on here?  Static electricity.  Free electrons easily build up on the surface of a balloon.  Many of you have probably observed this when rubbing a balloon on your hair and sticking it to wall.  The same concept is taking place here.  The rubber granules, being small and having a low mass, are easily pulled to the balloon's surface through an electrostatic force.  The electrostatic force is greater than the gravitational force trying to pull the granules back to the ground.  Thus the granules stick to the balloon.  

A bit later I was examining the balloon/granule interactions.  I knelt down on the turf, probably causing many confused looks among the other parents, and watched the granules appear to fly upward.  It was cool sight to see.  As I guided the balloon along the turf, a couple of centimeters above the surface, I could see the granules bouncing along the turf and flying up toward the balloon.  Very cool!

So what can you do?  Blow up a couple of balloons and let your kids see what they can do with static electricity.  Rub the balloons on your hair, clothes, carpet, etc.  What works best for building up charge?  Which surfaces do the balloons stick best to once charged?  Science in action!

Growing Dinosaurs Revisited

A couple of weeks ago I discussed a set of Growing and Shrinking Dinosaurs my daughter received as a gift.  Place the dinosaurs in water for a day and they grow up to 400% their original size.  Let them dry out and they shrink back to their starting size.  In the previous post I commented on the disappointment I always had with these as a kid.  Reality never matched my expectations.  The same was true for these dinosaurs.  They simply didn't grow as big as perceived in my mind (or my daughters' mind).  I'm happy to report, however, that the size they grow to increased after a couple of times getting wet and drying out.

They now grow to about twice the size they originally grew to.  My daughters thought this was very cool.  Also, the dinosaurs get brittle when wet, thus the decapitation of two of them.  LOL!

This makes me wonder if I gave up on these things too soon as a kid.  If only I had tried them a few more times, they would have grown larger.  Hmmm.  Patience is a virtue!

This Blog's History: Changing Color of Water Experiment

This Friday in This Blog's History I bring back to you the Changing Color of Water Experiment.  My 4 year old got a kick out of this one, and since has asked us several times if we can do it again, usually with the twist of throwing a food item into the water too!  LOL!  Check out the full details of the experiment in the original post.

Changing Color of Water Experiment

Reading in the Dark

A common phrase we've all likely heard at some time or another is that reading in the dark (or poor lighting) is bad for your eyes.  Is that really true?  I often find my daughters reading in poor lighting and I always tell them to turn a light on so they can see better.  I've never told them it's bad for their eyes to read in the dark, but I tell them because I find it odd that they choose to read in the dark.  :-)

Since I wasn't sure if reading in the dark is bad for your eyes, I decided to do a bit of research to find the truth.  It took a 30 second Google search to learn that one shouldn't worry if they consistently read in the dark.  Reading in the dark can strain your eyes and potentially cause headaches, but it doesn't weaken your vision.

Myths About Your Eyes and Vision

So let your kids read in the dark if they want.  I find it weird, but there's no damage done, so no worries.

Blowing Out a Candle Experiment

We all know how to blow out a candle, but can you blow out a candle when something is placed between you and the candle?  How do you blow out a candle if something is blocking the air from reaching the candle?  The trick is placing the correctly shaped object in front of the candle.

Start by lighting a candle and placing a rectangular shaped object (we used a paperback book) directly between you and the candle.  Hold the book so it doesn't tip over and blow directly at the book, in line with the candle?  Does the candle flame go out?

Now take a circular object, about the same width as that of your chosen rectangular object.  We used an empty two liter pop bottle.  Repeat for the bottle.  What happens to the candle flame?  Does it go out?  Here's the video of our experiment.

Why did the candle go out when blowing at a same sized two liter pop bottle?  When blowing at the rectangular shaped book, most of the air is deflected by the edges of the book away from the candle.  Thus the candle remains lit.  When blowing at the bottle, some of the air will "stick" to the bottle and follow the curvature, directing it toward the candle flame.  Thus the candle is blown out.  Very cool!  Give it a try and expand on this experiment by trying objects of different sizes and shapes.  Which "block" the air from reaching the flame and which do not?

Do Twinkies Last Forever?

You've likely heard the statement that Twinkies last forever.  Although forever is usually meant to be several years or decades, that's still a long time for a food product to remain fresh.  Is this really true?  Why does this misconception exist?

To be blunt, no, Twinkies do not last forever, or decades, or years.  The shelf life of a Twinkie is now 45 days, up from a previous shelf life of 26 days.  Forty five days is a long time, but no where near close to years or decades.  The misconception comes from another misconception that Twinkies are made from chemicals and are therefore not real food.  Don't even get me started on 'chemicals'.  All food products are made of chemicals.  Water is a chemical!  So to say Twinkies are made of chemicals and this causes them to stay fresh forever.  Of course they are made of chemicals!  Twinkies are no different than bananas or apples in that regard.

This misconception presents a great opportunity to setup your own science experiment with your kids.  Buy a box of Twinkies and investigate them over several months, or even years if you have the patience.  How does the Twinkie change?  Does its smell change?  Texture?  Look?  Ask you kids to note the changes.   Twinkie science!

Do Fingernails Continue to Grow After Death?

Do fingernails continue to grow after death?  I'll admit I hadn't heard of this misconception until recently and in fact had never even thought about fingernails after death.  The misconception states fingernail growth contains after one dies.

Where does this misconception come from?  It comes from observing corpses and noticing nails that are consistently longer than they were before the corpse became a corpse.  I'll spare you the gruesome images, but do a Google image search for fingernails after death and you'll find many images of corpses with long finger nails.  

The truth?  Fingernails stop growing at death.  Why then do they look longer?  Fingernails on corpses look longer because skin begins to shrink after one dies.  This pulls back the skin at the edge of the fingernails, revealing more nail and giving the appearance of growing fingernails after death.  

Now you know something you didn't know before reading this blog.  :-)

This Blog's History: How Long Does it Take for Chewing Gum to Digest?

We've all had someone tell us not to swallow chewing gum, often with the threat of that gum staying in our stomach for several years.  Is that really true?  I first discussed this last month and bring it back for This Friday in This Blog's History series.  Check the original post below for details and an answer.

How Quickly Does Chewing Gum Digest?

The Leap Second Debate

Who thought that a single second could cause such a problem?!?!?  Let me begin with the definition of a leap second.  A leap second is a single second added to official clocks every now and then to keep clocks based on Earth's rotation matched with extremely accurate atomic clocks.  The reason this is needed is due to the fact that Earth's rotation is very slowly slowing down.  This requires us to add seconds to the clock every now and then.

The last leap second added to our clocks occurred in 2012 and a total of 25 leap seconds have been added since 1972.  Not a lot, but over time it becomes a bigger issue.  So what's the problem?  Every time a leap second is added, it causes problems with computer software programs not fully capable of easily handling the extra second.  In 2012 this caused many major websites to experiences issues.  Those issues were fixed, but fixes cost money and in a world increasingly dependent on software, that money adds up.

It's time to add another leap second since we are 1 second ahead of Earth's rotation.  There's a debate on whether a leap second should be added this coming June.  On one hand, keeping up with Earth's rotation is important.  On the other, it's just a second and many argue the technology problems outweigh the differences in clock times.

There's a vote coming up to abolish the leap second (how do I get on that committee!)  If the leap second is abolished, the world's clocks will move further and further ahead of Earth's rotation.  Again, it's not a lot, but by the year 3015, we'll be 16 minutes ahead of the Earth.  If civilization survives for thousands of years, those seconds turn to more minutes and eventually turn to hours.  Eventually something must be done as 10 AM will one day represent the middle of the night.

Star Trek: The Next Generation

As a kid I remember watching several episodes of Star Trek:  The Next Generation.  I loved the show as a kid, although I didn't watch too many of the later Star Trek series.  The show streams on Netflix so I've recently introduced the series to my two daughters.  I wasn't sure how they'd take it, but they both love it!  If I mention an episode, they get excited and sometimes my older daughter will ask me if we can watch an episode.  I love it!

If you're looking for an excellent sci-fi show for you and your kids to watch together, you can't go wrong with Star Trek:  The Next Generation!

New Horizons Spacecraft

The New Horizons spacecraft was launched in 2006 with the goal of flying by Pluto to take the very first close up images of the former planet before continuing on to possibly observe other objects beyond Pluto.  The spacecraft was placed in hibernation for its long journey and just recently awakened from hibernation.  Upon waking up, it snapped a photo of Pluto, seen below.

Doesn't look like much and isn't much better than current images, but New Horizons still has a ways to go.  New Horizons will begin its first flyby of Pluto on July 14, 2015, so expect images to improve as we get closer and closer to this date.  I have to admit that I'm super excited for these close approach images to arrive.  We've never before seen the surface of Pluto well enough to identify pictures.  It doesn't get more exciting than finally seeing the unknown!

Be sure to show your kids images of Pluto as they come in.  The best source is NASA's New Horizons mission page.  Check it out for more detailed mission info.

NASA's New Horizons Mission

Baking Soda Stalactites

After our modified Jello experiment, my daughters and I set out to make baking soda stalactites.  In principle the experiment is easy to set up.  It requires two jars of water, both filled with dissolved baking soda.  Next take a string, dropping each end into each jar of water.  Let the string droop between the jars over a plate.  You made need paper clips or weights to keep the string submerged in the water.

Over a few days, the water should travel up the string and drip onto the plate.  The baking soda carried with the water will remain in the string, slowly creating a hanging stalactite.  That's what is supposed to happen.  That did not happen in our experiment.  Stalactites built up, but only at the string just as it emerged from the water.  Water did not soak through the string as expected.

That clump on the string is a baking soda stalactite ball.  One formed coming out of each jar.  So the experiment worked, sort of.  We created stalactites, just not where we thought we would.  So what went wrong?  I'm not sure.  My guess is the string.  We may need a thinner string.  The string was on the thicker side and this may have prevented baking soda water from traveling all the way to the middle.  We gave ourselves the task of getting different types of string and testing out which works better.

The experiment didn't work out as planned, but we have ideas to move forward and that's science in action!

This Blog's History: The Truth of Measles

About a month ago I wrote about the truth of measles and the harm the anti-vaccination groups are doing to others.  For This Friday in This Blog's History I'm providing the link to that post again.

The Truth of Measles

Measles kills.  Measles is preventable.  Get vaccinated!

Weather vs. Climate

Thus far in 2015 temperatures have been below normal in much of the midwest and eastern United States.  Many places have received great amounts of snowfall.  Too often, snow and cold are used as "evidence" that global warming and climate change are a hoax.  Sigh.  Just the other day my 7 year old was working on a homework assignment focused on the difference between weather and climate change.  It's a second grade lesson that EVERY human being needs!  Just because it is cold at your house does not mean climate change is a hoax.  Let's look at the difference between weather and climate.

Weather:  Weather is the day to day conditions in a particular place at a particular time.  For example, if I hear that it will be 25 degrees F tomorrow with 4 inches of snow, that's weather.  It has nothing to do with global warming and/or climate change.  It may be cold at your house but extremely hot at someone else's house.  While the midwest and eastern U.S. have been colder than normal, the western U.S. and much of the world has had much higher temperatures than normal in 2015.

Climate:  The average weather conditions in an area over a long period of time.  Note the last part of that sentence.  A long period of time.  For example, if I read that the month of January in my area averages 29 degrees F with 5 inches of snow and average wind speeds of 15 mph, that's climate.  The conditions on any given day (weather) could be drastically different from climate averages.

If the average temperature of the planet is slowly increasing, it can still snow!  It can still be cold!  That's still weather!  However, the climate, the long term changes in weather, is showing a warmer planet.

My 7 year old daughter in second grade understands the basics of weather and climate, but a good chunk of the world's population can't.  That's sad.  For more information on weather and climate, check out the following links below.

NASA - Weather and Climate

NOAA - Weather and Climate

National Snow and Ice Data Center

Jello

The other week my two daughters and I set out to do a Jello-related science experiment my 7 year old found in one of her books.  The goal was to make Jello-like molds that then hardened into Christmas tree type ornaments.  Unfortunately, part way through the experiment, I realized we were missing a key ingredient.  At this point we had a big bowl of lemon Jello that no one liked and no science experiment!  What to do?  We did what any budding scientist would do.  We experimented!

We decided to see what happens to Jello as it gets old, sitting on the kitchen counter.  So we let the Jello settle, cut out some shapes, sat those shapes on a plate, and patiently waited for a few days to go by.  Each day we took a look at the Jello to see how it had changed.  After a few days we had the following:

It's hard to tell from the picture, but the water in the Jello slowly evaporated, leaving the Jello tougher and tougher each day.  By the end I had to scrape them off the plate.  Although this experiment didn't turn out like we intended due to missing ingredients, we pressed on and learned something from it.  We learned that the water in the Jello, just like water in a glass, evaporates into the air.  The gelatin in the Jello does not.  It remains behind leaving us with very tough, inedible, Jello pieces.  

The moral of this story is to use your science skills to make something out of what started out as nothing!

The War on Science: National Geographic

I was very excited to see the latest issue of National Geographic arrive in my mailbox a couple of days ago.  I haven't had a chance to read it yet, but the cover, as you can see below, is about the constant war on science.

The cover mentions climate change, evolution, the moon landing, vaccinations, and genetically modified food.  In the scientific community, there is no doubt on the facts of each of these issues.  Climate change is real.  Evolution is real.  The moon landings are real.  Vaccinations really do save lives.  Genetically modified food is as healthy and beneficial as organic.  Yet each of these is debated hotly among the general public.  Why?  I'm really not sure.  In the internet age, it is extremely easy to get the facts on any issue, but at the same time, it is very easy to find false and/or misleading websites.

We're living in a day and age where a random person with a website is more trusted than a doctor with years of training or a scientist with decades of work in his/her field.  This is one of the reasons I write this blog.  There's so much misinformation floating around that I feel it necessary to put the facts out there.  By no means do I expect readers to trust me.  I usually post links to reputable science sources for readers to further research on their own.

If you haven't, I highly encourage you to check out this issue of National Geographic.

Quiet After Recent Snowfall

You're probably aware of different sounds surrounding you every time you walk outside.  Ever notice these same sounds after a freshly fallen snow?  If you haven't, try it sometime.  You'll notice that what you hear is MUCH different than a normal day with no freshly fallen snow.  You'll notice that it appears MUCH quieter after a snowfall.  Why is this?

Freshly fallen snow is not a good reflector of sound waves.  The snow is filled with many small gaps that work to absorb sound waves.  Waves that are absorbed do not reach your ears.  If more waves are absorbed, your ears will detect fewer waves, thus leading you to hear less than a normal day.  Once the snow has a chance to melt and/or harden, it becomes more reflective and waves reach your ear as normal.

Check it out the next time it snows and ask your kids what they hear and how things are different than before it snowed.