Doing another post, I came across this useful site that has a large collection of interactive bio animations on a host of topics and thought it was worth sharing.
Monthly Archives: August 2011
A New First Day
Today was my first day tutoring at the local community college. Given that it was the second day of classes and we had a hurricane yesterday it wasn’t terribly crowded, which was actually kind of nice to be able to sit for awhile with the few students who came in and try and connect with them early on.
The first student I had was working on simple conversions (e.g. how many mm in 3 cm, how may mL in 2 quarts, etc.). He was struggling a bit, partly because he was rushing and partly too because he was getting lost “in the weeds” as they say. He was going into each one somewhat anxiously and getting bogged down in the numbers without first stepping back and figuring out what he was trying to accomplish in a broader sense.
We did a decent number of conversions and I kept trying to get him to write the steps out explicitly, cross out units as he goes, make sure he labels the units with each number, etc. It was funny because skipping steps, not writing out steps, etc. are all the same bad habits I used to do when I was that age. It is just laziness and it is only with the benefit of hindsight now it is clear how much easier chemistry can be when you write out all the details.
It was a good first day. It is so incredibly rewarding, even on a small scale to be able to help someone do something they couldn’t do a few moments before and see that “Eureka!” moment when it clicks in their brain and they own it for the first time.
Fun Facts Fridays – Hurricanes!
Another tradition I would like to start with this blog is on occasional Fridays listing 10 (and only 10) fun facts (fun as defined by me) about anything that pops into my head that seems interesting at the moment. Since we just survived Hurricane Irene here in the northeast, it seemed apropos to start there. So…hurricanes…
Hurricane Isabel
10 Fun Facts:
- The cold water off the western coast prevents hurricanes from surviving there. Hurricanes get their moisture by the evaporation of warm waters.
- They are “hurricanes” in the Atlantic, “typhoons” in the western Pacific, and “cyclones” in the Indian Ocean. They are all names for the exact same type of storm.
- The Earth’s coriolis effect causes hurricane’s spin and movement towards the poles.
- The deadliest hurricane ever was the 1970 Bhola Cyclone that slammed into Bangladesh and killed around 500,000 people!
- The largest hurricane ever recorded was Hurricane Carla that struck Texas in 1961.
- The general mechanics of a hurricane are as such:
- Warm water (at least 78°) evaporates off the ocean, creating a relative vacuum that draws in more air. The warm moist air condenses to form clouds/rain which releases heat that warms the cool air above, which rises creating room for more air to get sucked in, etc. It is a positive feedback cycle.
- Converging surface winds help push the warm air up even faster, and strong upper atmosphere winds blow the risen air out away from the center. This further perpetuates the cycle to create a significant low pressure zone that begins to rotate (coriolis effect) around an “eye”.
- As air rushes in from the area of relatively higher pressure into this area of extreme low pressure, wind speed increases significantly…alas you have a hurricane.
- The World Meteorological Organization keeps a 6 lists of storm names (each list has 21 names) that they cycle (no pun intended) through every 6 years. Whopper storms have their names retired so they are not used again.
- Florida wins the prize for the state where the most hurricanes have landed (110 total; 35 major ones of Cat. 3-5)
- There is a long list of retired hurricane names (NOAA Retired Hurricane Names)
- The word “hurricane” comes from the Carib tribes of the West Indies who called these storms “huracan” after one of their gods. Spanish colonists changed the name to hurricane.
Here is a good explanation on how hurricanes work…
There She Blows!
So this is another entry from our Rainy Day Science Demo. This is a classic one…the old vinegar meets baking soda reaction that is the centerpiece of every volcano project in elementary school. To make it a little more interesting, we decided to forego the volcano aspect (well maybe “more interesting” is not the right phrase) and use a balloon to trap the gas created by the reaction. Some shots from the scene…
The Analyst adding some vinegar to our water bottle.
Putting baking soda into a balloon using our homemade funnel - by far the trickiest part of the demo; the baking soda kept clogging up in the funnel.
The Actress placing the balloon over the top of the bottle as The Analyst blows up balloons in the background. Trying to teach a science lesson here and the package of balloons was the highlight of the event!
Tip the balloon so the baking soda dumps into the vinegar and what do you get? A blown up balloon of course!
So after the initial demonstration we attempted to turn it into a simple experiment. I posed the question: “What do you think will happen if we have more baking soda in the balloon?” The answer out of my little budding scientists…”It will blow up more!” The beginning of their first hypothesis!
4T of baking soda instead of 2!
It certainly blew up more. In fact it blew the balloon off and splattered acetic acid onto the ceiling (found a week later)!
The Science Behind It…
So what is going on here anyway? Well this “reaction” is actually two reactions that happen in quick succession. To start with, vinegar is acetic acid (CH3COOH) and baking soda is sodium bicarbonate (NaHCO3). What happens when they mix is a simple double replacement (AX + BY –> AY + BX) acid-base reaction:
CH3COOH(aq) + NaHCO3(s) —> CH3COONa(aq) + H2CO3
The sodium and hydrogen ions essentially “switch places” (. The sodium replaces the H in the acetic acid to form sodium acetate. Simultaneously the displaced hydrogen ion replaces the sodium to form carbonic acid. Carbonic acid is a weak acid that quickly undergoes a decomposition reaction (AB –> A + B) to form carbon dioxide and water:
H2CO3 –> H2O(l) + CO2(g)
What you are seeing filling up the balloon then is the CO2 gas that has escaped from solution.
“Website Wednesdays”: Good Source for Interactive Biology Tutorials
Cellular Respiration in Action!
Did a fun demonstration with The Crew today that nicely demonstrates cellular metabolism. It is a pretty common lab in high schools (done a little more scientifically that the Crew could handle) and involves yeast metabolizing glucose and producing CO2. Here are some pics from the scene…
The Actress looking ever so happy creating our sugar solution for the little fungi to feed on.
The Analyst pouring our sugar solution into our ubiquitous plastic water bottle.
The Actress pouring our little "beasties" into the sugar solution.
We had a lot of fun with the topic of yeast. The Crew was completely fascinated that we were going to buy something “alive” in a package at the grocery store and asked over and over again if they could open it, what did they look like, etc. Needless to say they were a little disappointed little critters didn’t come jumping out of the package when we opened it, but that went away as we continued on with our little demo.
S. cerevisiae
For a bit of background on yeast…Yeast is one of the most useful and most carefully studied eukaryotic organisms in nature. In fact, the same species of yeast sold in the grocery store (Saccharomyces cerevisiae) was the first fully sequenced eukaryotic genome in 1996. They belong to the kingdom Fungi (along with molds and mushrooms) and have a huge number of uses from baking to alcohol fermentation in beer making and even some potential applications in bioremediation of hazardous chemical spills. For more about yeast.
The Crew putting the balloon on top of the bottle to capture any escaping gas.
Presto! After 20 minutes or so our balloon starts to inflate. But with what??
After about 40 minutes, our balloon is almost fully inflated. The Crew was impressed!
The Science Behind It…
So what is that mystery gas in the balloon anyway? Why is is CO2 of course! That ever famous byproduct of cellular respiration. You remember, the old dreaded…
C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy (as ATP)
or…Glucose + Oxygen –> Carbon Dioxide + Water + ATP (the energy currency of cells)
or…Glycolysis –> Pyruvate Decarboxylation –> Kreb’s Cycle –> Electron Transport Chain
or…
Kreb's Cycle after completion of Glycolysis
Now did I go into any of this with the Crew? No, we were content with “cool – look – the little creatures eat and breath and what they breath out blew up the balloon” – maybe we will do the aerobic and anaerobic biochemical pathways next week!
What is nice though is being able to see these reactions occur in the real world. It makes it all a lot less abstract.
Like Oil and Water!
The Crew and I did a couple of simple kitchen science demonstrations today since it was raining. The first we did was investigating the relationship between oil and water. A simple demonstration, it shows how no matter how hard you try to mix oil and water together, given a couple of minutes they will always separate due to the hydrophobic properties of oil. A few pics from the fun…
The Actress getting some water to start...
The Analyst pouring the water into our highly scientific plastic water bottle. We then added some food coloring to more easily see the separation.
The Actress adding the vegetable oil on top of the colored water.
Giving it a vigorous shake to mix. The kids had a lot of fun trying to shake the bottle harder and harder and were amazed that the oil and water would separate each time, no matter how hard they shook!
At first, the oil and water look like they are fully mixed, but give it a few minutes and they begin to separate. You can see some slight emulsification (the pinkish hue to the oil on top) but give it more time and they completely separate again.
After a few rounds of that, with each of them trying harder and harder to get the two to mix, we decided to add liquid soap to act as an emulsifying agent that would give us our somewhat homogenous mixture…
Adding our emulsifier!
After a good shaking and letting it sit several minutes, still not separated!
The Science Behind It…
So why don’t oil and water mix anyway?
Well, as mentioned above, oil is a hydrophobic molecule, it is a triglyceride that is completely saturated with hydrogen and thus does not have significant charge (i.e. non-polar).
Vegetable Oil Molecule
On the other had, dihydrogen oxide (i.e. “water”) is a polar molecule where the oxygen atoms hogs the electrons of the two hydrogen atoms giving the molecule a significant dipole (negative charge around oxygen and positive charge around the 2 hydrogen atoms).
A salt crystal dissolving in water. Look how the water molecules surround each ion, with the hydrogen side surrounding the negative chloride ion and the oxygen side surrounding the positive sodium ion.
In fact, it is this polarity that allows for things to dissolve in water. There is an old saying that “like dissolves like”. For water as a solvent, this means
Oxygen hogs the electrons from hydrogen, giving the molecule regions of positive and negative charge (polarity)
the negative and positive regions of a water molecule form bonds with the negative and positive regions of a similarly polar solute molecule (often ionic compounds; e.g. salt). The water molecules surround the ions creating a solution. Here is a nice graphic of how NaCl (table salt; an ionic compound) dissolves…
Since the oil hydrocarbon doesn’t have this polarity, there is nothing for the water molecules to interact with. In fact, they would rather form hydrogen bonds with other water molecules (since they also have a charge) and the oil essentially gets “chased away” by the water. Since oil has a lower density than water (~894 kg/m³ vs. 1000 kg/m³), the oil floats on top.
So what does the dish soap do?
In essence, dish soap (an emulsifier) acts to “bridge the gap” between the polar water
molecule and the non-polar oil molecule. Soap is a long molecule with a polar “head” and a long non-polar “tail”. So when we added soap to our oil/water mixture, the soap’s polar head interacts with the polar water molecules and the non-polar tail interacts with the non-polar
oil molecules. It is like a mediator that brings two antagonistic people together. With the soap added, when our bottle was shook it created all these little bonded groups of water-detergent-oil.
The hydrophobic tails of soap molecules surround an oil molecule.
This is the same principle as how detergents clean clothes and dishes. They surround the oil/grease particles, unbinding them from the plate/fabric and then get “washed away” as water is run over them.
Leaf Identification w/ the Crew
The Analyst, The Actress and I took a neighborhood tour the other day to identify the kinds of trees that grow around us. With bucket in hand, we walked the street and took samples (one for each of them) of as many different kinds of trees as we could find. The first thing that was surprising was there was not a huge amount of variety. Tons of maple trees…so many in fact that The Actress suggested our road should be named Maple Drive (it’s not; in fact it is named after another tree that we found only one single sample of). Here are a few pics from our adventure:
The Analyst examining a leaf
The Actress showing off a leaf!
After we got back to the house, they spent some time arranging their leaves into a display and gluing them in place…
Making a collage of leaves from the Neighborhood!
With the leaves secured in place, we found a useful leaf dichotomous key application online. It was a nice program that was great exposure to the kids of leaf terminology (e.g. venation, teeth, lobes, scales vs. needles, etc.) The Crew was immediately comfortable answering the key’s questions and was quickly having a blast identifying and labeling the leaves they had collected.
Using the Dichotomous Key
With their leaves labeled, the Crew displayed their results for Mom to see in the kitchen when she got home!
In all, it was a great way for the kids to learn a little about the kinds of trees we have in the neighborhood and a great chance to learn a little botany terminology!
Our First Geocache!
The Actress and The Analyst with their first Geocache!
We have talked about going Geocaching for a long time and up until now I think the kids were probably a bit too young for it (the patience, the hike at times, etc.) but on a recent trip out to the summer place we finally went in earnest and had success on our first trip out! It was very fun and is literally like real life treasure hunts for kids. They are still a bit too young to truly understand what the GPS coordinates mean and how to operate the GPS receiver (BTW, I just used a free app downloaded onto the Blackberry – “Northstar” I think?) but they still got very into it and were so excited once we found our cache. We found it in Montauk at the “Teddy Bear’s State Park” (hint, hint). Nicely hidden, fun swag and good log. Very nicely maintained for our first find. I think we took a plastic figure and left a penny (all we had – sorry! – better planning next time).
For those of you not familiar with Geocaching, essentially it is where people have placed small treasure “caches” at specific GPS coordinates all around the world. After looking up the coordinates on the website (we use Geocaching.com), you use your GPS receiver to go to those coordinates and look for the cache. Once find, you customarily sign the log and if you want take a token item and leave a token item in the cache. Again for kids it is a lot like treasure hunting and you can play up the secrete society aspect (non geocachers are called “Muggles” as a nod to Harry Potter, etc.).
We had a great time and I think the kids are hooked. We even decided on a club name for us (GeoJedis – a nod to The Analyst’s obsession with all things Star Wars).
GPS
Chance to sneak in some science. After our first geocache find I wanted to learn a little about GPS to explain it to the team. I found a good tutorial on How Stuff Works (How GPS Receivers Work). In a nut shell, your GPS device uses the time lag between a semi-random code sent out from the device and from 1 of 24 GPS satellites circling the earth to determine the distance from that satellite to your receiver. By doing the same thing with 3 other satellites it can determine your exact position using a process of trilateralation. Here is a good image of how trilateralation works (simple 2D version):
A good textual explanation is given at the How Stuff Works site and has a decent Flash gallery on how it translates to a 3D version in real life. After correcting for errors using a regional GPS receiver of known location, the devices can get pretty accurate (maybe ~ 20′) to where exactly you are.
Introductions & Eye Color
So one of the things I intend to do with this blog is share our family adventures and some of the science/nature adventures I have been having with my kids now that they are old enough to appreciate such things. As such, I think some introductions are in order (with some respect for privacy):
The Wife
I haven’t always made smart decisions (I still regret not becoming a teacher straight out of college – no matter how much my real estate career afforded us), but I married VERY well. In short, the wife rocks. She is incredibly patient with all my absent-minded professorness (what we call me never knowing where my keys are), my hobbies (I fish a LOT) and everything else. She is beautiful and has this just way about her. The only way I have ever been able to describe it to her is she has “grace”. She can make ANYONE comfortable and knows everything about someone in short order. There are people I have met 10 times and I can barely tell you their name. Above all, she had to take a huge life adjustment and return to work after the real estate thing ended. She is a trooper for sure!
The Analyst (Age 6.5+)
My oldest son is almost a carbon copy of me. He is awkward in social settings, has no issue being by himself for hours on end, not entirely athletically gifted, but a warm, empathetic kid whose heart is in the right place 100% of the time. He is my analyst. He needs his ducks in a row, loves to get to the details of things, thinks intently (to a fault like his dad) about most things and is very emotional. He is obsessed with Legos and has just shown the beginnings of a fishing obsession (which I happily encourage). He is a really neat kid.
The Actress (Age 5+)
My daughter is physically the carbon copy of my wife (from me she gets hair texture (fine) and tanning ability). Personality-wise we are not quite sure where she is from. We call her the actress because I am not sure I have met a more melodramatic person in my entire life. Unlike The Analyst, she has not interest in intellectual pursuits, but simply wants to talk to everyone in the entire world, play, dress up in fancy clothes, be the damsel-in-distress, etc. No interest in sports at all (she defines a girly-girl) but is incredibly in tune with the emotions of everyone around her. She is a classic expressive-driver (at some point I have to do a post of personality styles – of which I am a huge believer). She is also the world’s best cuddler. She is my princess.
The Buddy (Age 2+)
It is tough to know a lot about the personality of a two year old and the verdict is still very much out on this one. I think this youngest son of ours is all boy – rough, tumble, dinosaurs, trucks, etc. He is a fickle little guy who switches his allegiances from mom to dad at the drop of a hat but he is my little buddy. The one thing he got from me is accident proneness. He has at his tender young age broken an arm, sprained his ankle and lost a tooth. Poor little guy.
The Dog
Rounding it out is our boxer. She is a monumental paininthebutt (I knew boxers were high energy when we got her but come on!) but we love her and she is a wonderful nanny to the kids.
So that is the fam. You’ll see them around in these posts.
A quick chance to get a little biology in… How cool heredity and genetics. How cool is it that The Analyst has my hair color (blond) but wife’s hair texture (thick) and The Actress has my wife’s color (brown) and my texture (fine). Very cool stuff.
The Actress also demonstrates that eye color is not the simple Mendelian genetics of brown eye dominant -blue eye recessive that is so often taught. Both me and The Wife have blue eyes (mine are paler blue than hers). The Actress has brown eyes. Now if it were simple Mendelian that would be impossible as my wife and I would be a cross of homozygous recessives (blue x blue). But eye color is actually a complicated process of polygenetic inheritance (phenotype involving more than one gene), partial dominance (where one allele is not completely dominant over another) and epistasis (where Gene A controls the expression of Gene B). It is a careful mix of the type and amount of melanin present in the iris. Phew – no paternity test needed ;-)!
Beyond the Genome, Cancer’s Secrets Come Into Sharper Focus – NYTimes.com
Beyond the Genome, Cancer’s Secrets Come Into Sharper Focus – NYTimes.com.
This is an interesting article on the fascinating web that makes up cancer, including “pseudogenes”, “microRNA”, and the way cool symbiotic relationship that exists between us and microbial organisms. �I am utterly amazed at just how beautifully complex the world is. �I mean how cool is it that humans in Japan have developed a relationship with a microbe that assists in the digestion of seaweed (and thereby sushi’s seaweed wrappers)??
The Backyard Biologist! 