Tuesday, December 11, 2012

The Geminids

The Geminid meteor shower is coming up! At 2:00 AM, on December 14 (that's Thursday night, or Friday morning), you can see anywhere from 100 to 150 meteors per hour - depending on the sky and weather conditions. That's more than 1 meteor per minute!

This particular meteor shower comes from a 5.1 km wide asteroid called 3200 Phaethon. Flecks of debris fall off this asteroid in a trail around the sun. These bits are called meteoroids.

Every year, in December, Earth passes through this stream of meteoroids; when one of them enters Earth's atmosphere, it burns up and we see a meteor. If the meteor is brighter than Venus, it's called a fireball. Fireballs are much less common than meteors.

This year, viewing conditions will be especially good; the peak occurs only 1 day past new moon. If you live in an area with lots of light pollution, you will definitely want to drive into the country. If you think the weather will be bad, go out a day or two before or after the peak. Keep warm, and good luck!

Friday, December 7, 2012

Night Turns to Noon


You might want to check out my Blue Moon post before you read this one.

It was late at night. The full moon lay high in the starry sky. Suddenly, everything started getting brighter and brighter, until the moon was as bright as the sun, and everything looked the way it does in the middle of the day - except for the glaring light pollution and the burning stars. Astounded, I pulled out a camera and snapped the photo above, and some others you can see in my Blue Moon post. About an hour later, everything went back to normal.

Does that sound like a true story? Well, it isn't; that night was just like any other. To take the photos, I used a trick that I will explain in this post.

When a digital camera takes a photo, this is what happens: a shutter on the front opens up, and a lens focuses light onto a tiny charge-coupled device (CCD) inside the camera. When the light hits the CCD, a small electric charge becomes present. As more and more light hits that part of the CCD, the charge gets stronger and stronger. Different parts of the CCD have different charges, depending on how much light they get.

After a certain amount of time, called the exposure time, the shutter closes, and the camera converts all those charges on the CCD into an image. The bright parts of the image correspond with stronger charges on the CCD, and vice versa.

Now let's go back to the photo I took in the moonlight. Since it was dark outside, the charge on the CCD would have been very weak, resulting in a dark image. But what if there were a way to make the charge stronger? Then I would have a much brighter image; if things worked well, the image might look as if it were taken during the day.


The trick is simple: change the exposure time. If you set the exposure time higher, then the shutter will stay open longer; the charge on the CCD will be much stronger, and you will have a much brighter image. That's what I did, and the results (not to mention the bragging rights) are certainly worth the time.


Hopefully this post explained some things about cameras and tricks. If you can remember what I said, and can put it into practice, you're well on you're way to becoming an expert photographer. Finally, here's a tip: if you're trying to take a "daylight" photo, don't let any houselights get in the picture. They'll get brighter too, just like everything else.

The video above shows a series of photos taken with different exposure times.
The first photo has the shortest exposure time, and the last one has the longest.

Friday, November 9, 2012

Pictures from October

These are some of my pictures from October. Some may have been trimmed, but most were not. To see a larger view, click on the image.

First are some pictures of black-billed magpies, one of the most common fall/winter birds where I live:




And here are some contrails. Contrails are the clouds which airplanes leave behind them.

Contrails
The next 3 pictures were taken through some stacked loupes my mom gave me. See if you can figure out what they are.




Now here's a picture of the moon. It was in its waxing crescent phase; "waxing" means "getting larger", and you probably know what "crescent" means.


This is a picture of one of our first snowfalls.


Now a kid in a costume.


Now here are some eggs. You might recognize them from a previous post.


Monday, November 5, 2012

Eating Eggs


Lately I've been eating much larger breakfasts than I used to eat. Almost every morning, I eat 6 to 7 eggs plus something good like a glass of juice or a fried sliced potato, or sometimes a bowl of cereal. This is very strange compared to what I used to eat: 2 bowls of cereal, or some pancakes. What happened?

Well, at one point my dad found some bowls of wasted cereal on the table. They weren't mine, in case you're wondering. So he decided to just stop buying cereal; if people waste it, why bother?

Now that my main breakfast food was gone, I had to find something else to eat. I had tried oatmeal before, and hadn't liked it a lot. I tried it again; still the same problem (as a side note, let me say that I never waste food if I have the choice). Eventually, I decided to try eggs.

A plate of eggs. I ate them all.
You may be wondering why I never tried that before, and the reason is that I don't like eggs without toast; without toast, what do you do with all that runny yolk?

Well, I didn't have toast, but I was hungry just the same. My sister was making eggs, so this was the perfect day to start. She asked me how many eggs I wanted. First I asked for 3 (because that was how many I usually ate). Then, realizing that I could definitely eat more than that, I changed my order to 4; then 5, then 6. She started protesting, and somebody even appealed to a higher authority: "Mom, he wants to eat six eggs! You can't let him do that!"

What, now was I a criminal or something? I only wanted to eat! But my siblings thought that eating so many eggs wouldn't be healthy, so I had to argue my case. In the end, I got my wish, but on one condition: that I would make sure my dad bought lots of eggs.

My uncle won an eating contest as a teen, and my dad ate multiple adult meals from restaurants as a teenager. I guess eating a lot is in my genes.

Thursday, November 1, 2012

Halloween

Yesterday was Halloween. Some people I know don't do anything on Halloween. I'm not one of them, and never have been; I've gone trick-or-treating every year since I was about 2 or 3.

When I first started, I didn't stay out very long, and at least one of my parents stayed with me at all times. Yesterday I stayed out for about 2½ hours with some siblings and a couple of friends, and would have stayed longer if I was allowed; the candy I get then is pretty much all of the candy I get for the next year. And it really does last that long. Even now, I still have a few pieces of candy left from last year! You might be able to guess that I'm proud of my self-control when it comes to Halloween candy. My other siblings finished off their candy many months ago.

The main idea for trick-or-treating is to dress up as something cool. This year I was planning on being a burglar, since I couldn't think of much else. My sister told me that she was dressing up as Buttercup from The Princess Bride (which is a really cool book, and also a neat movie). Bingo! I could be the Dread Pirate Roberts (from the same book), and then we'd match! So she decided to help me with my costume.

About a week ago, she decided to dress up as something else; but I still dressed up as the Dread Pirate Roberts. I guess he must not be a very well-known character; everybody kept asking me if I was Zorro (but that could be because they look so similar).

Saturday, October 6, 2012

Khan Academy

In this post, I'll tell you about a really cool new site I found: Khan Academy.

Khan Academy is basically a bunch of free tutorials for school subjects like mathematics, history, science, and just about anything else. And not only that, but they also have a special practice page that offers exercises, and when you complete enough of them you get points.

And here's one of my favorite things about it: they have a special section just for computer science, so I can write programs (mostly video games), and everybody else can see and play them. So far I've only written one program, but it's pretty good for my first (even though it's not finished yet). But one of the coolest things about that programming feature is that you can embed the program on a web page:

Super Ball

Another nice thing is the badges you get for accomplishing certain things. There are 6 types: meteorite, moon, earth, sun, black hole, and challenge. The easiest to get are the meteorites, and the hardest are the black holes (you don't even know how to get the black holes!). The challenge badges are just extra stuff. You can display up to 5 of your badges on your profile page for everybody else to see.

So check it all out - go to www.khanacademy.org! If you ever forget the link, just check my Links page.

Monday, October 1, 2012

A Blue Moon


Blue moon sounds like a moon that's blue. And it can mean that, sometimes. But that's not the real definition.

By the calendar, a blue moon is the second full moon of a month. The original definition (a seasonal blue moon) is the 3rd full moon in a season that has 4 full moons. Either way, a blue moon occurs approximately every 2.68 years.

The full moon of August 31st, 2012 was a blue moon by the calendar. I had to see it, because I won't see another for at least 2.68 years (I'll see a seasonal blue moon in August 2013, though). So I got a camera and a tripod and headed outside.

It was warm, and everything cast shadows from the moon's light. The first thing I did was to set up my camera and tripod and point it at my house. After changing the camera's settings, I took a picture. Here's what I got:

Tuesday, September 4, 2012

Guess the Details

Here are some pictures I took. See if you can guess some things about the photos:
  1. Approximately what time of day the photo was taken at, or if it's computer-generated
  2. Which parts of the photo were computer-generated, if any
  3. The season (for outdoor photos)
To view the images better, click on one. I'll give answers later.

House

Crayons

Calendar Blue Moon
Weeds and Grass

Saturday, September 1, 2012

Mathematically Diving

Diving can be done well or poorly, depending on how good the diver is. Sometimes, beginning divers will do "belly flops", smacking the water horizontally instead of cutting into it like a needle. Whether a dive is a good one usually depends on whether the diver went straight into the water or not. Experienced divers can do this without thinking much about it, as if it were like walking; beginners, however, have a lot more trouble.

In time, people get used to diving; machines, however, can't learn, and are always just as clumsy. If the machine contained a computer, it would need a computer program to help it dive. The program would need to use a math formula. Here's what we'll start out with: v1= v2 tan θ, where v1 and v2 represent forward and downward velocities, and θ is the vertical angle in degrees.

 

Here's how it works: the forward and downward velocities of a good dive have the same ratio as the sine and cosine of the vertical angle of the diver (represented by θ. See picture), so the formula is v1 / v2 = sin θ / cos θ. Since sin/cos = tan, the formula becomes v1 / v2 = tan θ; multiply both sides by v2, and you get v1 v2 tan θ.

To use the formula, you figure out what angle you'll be diving at and how fast you'll be falling when you hit the water (the downward velocity, v2). When you put those numbers into the equation, you can do the math and get your forward velocity (v1), so you know how fast you have to run off the diving board.

However, you might not know how fast you'll be falling (v2) when you hit the water, so let's calculate it now. If you fell h feet in s seconds, your average speed in the time you fell was h ft per s sec, which is the same speed as h/s ft per sec. Since acceleration while falling is as good as a constant (ignoring air resistance), and you start at zero, your final speed is twice your average speed: 2h/s ft per sec. Insert that into the equation and you get:

Now we have another problem: s, the amount of time before you hit the water. To get rid of s, we just need to state it in terms of another variable. After falling for 1 second, your speed will be 32 ft per sec. After s seconds, your speed will be 32s ft per sec. We also know that your speed will be 2h/s ft per sec. Therefore, 2h/s = 32s. Work it out and you get s = √h / 4. The very complicated equation you see to the right is what we have now. And if we simplify it, we get the final equation you see below.




Saturday, August 25, 2012

"Flipping Quarters" Solution

A couple of pieces of good news: First, in this post will be the answer to the problem I gave called Flipping Quarters; and second, I'll even work through the solution!

Friday, August 17, 2012

How I Got Blender


In a couple of my posts, you may notice some computer generated images or animations. They were created with Blender. In this post, I'll explain how I got it and started using it.

A long time ago, I wrote a BASIC program that drew a circle; the user would give the program a number, and it would draw a circle that size. There was a problem, though: the circle had a lot of holes in it. I solved the problem by filling the circle, but that was like cheating. I told my dad about the problem, and he showed me a book about graphics.

I looked through the book, but didn't find anything about my problem. I did find a section with nice, colorful computer-generated images, however - and some were so good they looked like photos! At one point, there was a series showing the construction of a photo-realistic image of a room, starting with the edges, then moving on to the surfaces, texturing, lighting, etc. Here's a similar series I made using Blender (but not photo-realistic):
Edges
Surfaces
Color
Lighting
Bump-Mapping, Reflections, Specularity, and Compositing
It looked so simple, I was hooked. I had to make my own computer-generated image that looked like a photo. I asked my dad to get me some software for 3D animations, so he searched on Google and found Blender. It looked like fun, and it was free, so we got it.

I followed some video tutorials I found on blender.org to make some nice images, and then I started making my own stuff. It was a lot of fun. I raved about it to my sister, but she just got sick of it and hated to even hear the name "Blender." Eventually, though, I convinced her to take a tutorial and make some balloons, and now she uses it to create images, like me. She uses it for art, but I also use it to show people how things work.

So that's how I got Blender. If you're interested in trying it out, just go to the download page on blender.org, and download it. Maybe you'll find it as fun and useful as I do.

Tuesday, August 7, 2012

Flipping Quarters

Here's an interesting puzzle involving chance:

A man in a park asks you to play a game with him. It's a form of gambling. To play, you must pay the man $5, then flip a coin repeatedly until you get heads. As soon as you get heads, you stop flipping. If you only flipped the quarter once, he'll give you $1. If you flipped it twice, you get $2. Three times, $4. Four times, $8. Each extra flip gets you twice as much money, so the longer it takes before you get tails, the more money you get.

Should you play, if you have a lot of time and the man will play as many games as you want? How much money, on average, would you gain (subtracting the $5 fee)?

I will give the solution in a later post.

Wednesday, July 18, 2012

Cumulus Clouds



Cumulus is the Latin word for pile or heap, and cumulus clouds certainly fit their name! They look like fluffy mounds of whipped cream floating in the sky, and often have a shape similar to that of a cauliflower.

 Cumulus clouds form when relatively warm, moist air rises and cools below the dew point. The moisture in it then condenses into tiny water droplets, which form the cloud. The relative humidity (how "full" the air is with water) helps determine the height at which the moisture condenses at, which is the base of the cloud.
In this little video I made, you can see how the clouds form, with the moist air appearing a light mist rising out of the ground. The moist air is not visible in reality, but I added it to help illustrate the idea:


A cumulus cloud constantly undergoes change, as long as moist air continues to rise under it. The water droplets at the edge of the cloud usually evaporate, so the cloud loses water as it gains it. In a time-lapse, the clouds appear to boil.

Here are the main types of cumulus clouds:

Cumulus Humilis

Cumulus humilis clouds are small things with little vertical development. They indicate that the temperature of the atmosphere in the area does not drop very much with altitude, if at all. When seen in the morning, they signify an unstable atmosphere, possibly resulting in thunderstorms.
These clouds are the most likely type of cumulus cloud to be seen during Winter.

Cumulus Mediocris

Cumulus mediocris has a greater vertical development than that of cumulus humilis, but is not as large as cumulus congestus. When these clouds are seen in the morning or early afternoon, they often indicate storms later in the day.

Cumulus Congestus

Also known as towering cumulus, cumulus congestus are tall, towering clouds that often precipitate (rain, hail, etc.). They are similar to cumulus mediocris, but are a lot larger and taller. They often develop from cumulus mediocris clouds, but may develop from other types of clouds as well. If this type of cloud continues developing, it can become a cumulonimbus cloud. The one in the picture above became a small one within a few minutes.

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Sunday, July 8, 2012

Bird-Watching


Few people watch birds very closely nowadays, or go to any lengths to identify them. That's their loss - bird-watching is fun, educational, and a way to pass the time when you're bored. After bird-watching for a year or two, you can identify birds a lot more easily, and you aren't as clueless when people ask, "What kind of bird is that at your feeder?"

So what do you need to bird-watch? Binoculars are essential; without them, many small markings can be indistinguishable. A field guide is also important. David Allen Sibley's guides are probably best, but anything will work as long as it covers your area thoroughly enough. And that's it. There are other little things that may be helpful, like a camera or a notebook, but these are all you really need.

If you already know a little about bird identification, then you're ready to start looking for birds to identify. But if you're a beginner, you may need a little more help. You might see a large black and white bird land in the snow, and open your field guide to figure out what kind of bird it is. You know the bird you saw must be somewhere in the book, but you don't know where to begin - and it would take you all day to check every single page.

I had the same problem when I first started identifying birds, only the birds were a lot tougher than a Black-Billed Magpie (the black and white bird I just mentioned). I checked the index, only to find a bunch of bird names. That wasn't helpful. I checked everywhere else, trying to find clues as to where I should look in the book. Still no help. In the end, I checked the whole book. I found a few birds that looked like my bird, but the bird was gone so I couldn't compare any more.

What should you do to prevent this from happening?

In good field guides, the birds are grouped according to family, or similar types; the ducks are with the ducks, and the ravens are with the ravens. This makes things simple; once you figure out the family, the possible bird types are greatly reduced.

For beginners, however, determining the family is exactly the problem. If you aren't good at recognizing bird families, try this: look at a lot of pictures of birds, and read about their habitats and behaviors. If you do this, it will make bird identification easier. The longer you spend reading about and studying a bird's characteristics, the more likely you'll be to recognize it when you see it.


Some tips:

- In The Sibley Field Guide to Birds, Sibley has a lot of good rules for birdwatching. Here's a quote: "Practice seeing details. Much of the skill involved in identifying birds is being able to sort out the details of the bird's appearance from a distance."

- Take a notebook with you when you bird-watch. If you see a bird, take notes on the bird's behavior, location and appearance. If you can draw a rough sketch, do that too.

- If you are having trouble identifying a bird, take a few photographs of it. Then you will have a record of it even after it flies away, which can be very helpful.

Swallow
A Violet-Green Swallow in flight
- Sometimes, bird families contain very different-looking birds. Believe it or not, bluebirds are in the same family as robins: both are thrushes. If you run into a family like this, you may wish to break it up and study each genus (a subclass of family) separately.

- Some common bird types to study are: Duck, Finch, Goose, Gull, Hawk, Hummingbird, Pigeon, Swallow, Sparrow. Even if one of them isn't in your area, study it anyway; chances are you'll see it on a vacation.

- When buying binoculars, try them out before you buy them. If you don't, you could end up with something that doesn't focus right, or worse.

Tuesday, June 12, 2012

A Big Thunderstorm


On the day after the June 5th Venus transit, which was the last until 2117, we had the first big thunderstorm of the year.

Before the storm, it rained. Usually we don't have rain followed by sunshine followed by more rain, so when it stopped raining, I thought that was the end of it. It wasn't. When I looked up at the sky, I saw some gigantic clouds. You know the puffy cumulus kind that float by on a sunny afternoon? Well, these clouds were similar to those, only about 20 times larger. These were cumulonimbus clouds - the most dangerous type of cloud. And they were heading my way.

Not long after I went back inside, it started getting dark. Rain began to fall, followed by hail. Lightning flashed again and again as the hail pelted against the windows. I heard that there were 3 tornado warnings. When I looked outside, I couldn't see very far at all, so a tornado could come and I might not even notice until it tore the roof off. I got excited, and started watching very carefully for tornadoes. I've already seen a tornado once, but that wasn't enough; I want to see a few more. Anyway, sometimes the hail would quiet down, so I thought there could be a tornado nearby. Other times it would start rumbling on the roof, so it sounded like a tornado was coming. And meanwhile, I ran from window to window, checking for tornadoes. I never saw any.

Some of the hailstones in that storm were really big - the size of Ping-Pong balls, and larger. Anybody that walked out into the storm wore buckets or metal lids on their heads. If a hailstone hit them on the head, it would hurt a lot - those hailstones fell so hard they even dented our cars, one of which was totaled!


Not only were the hailstones large, but they were numerous. They filled the gutters and rain spout, causing the rain to spill over the sides or leak into the roof. I saw water running out of an air vent in an overhang on the outside of our house. My dad went outside and cleared the rain spout so the rain could drain to the ground more easily, but he didn't realize the hail in the gutters was a problem until much later.

After my dad cleared the rain spout, I noticed that a lot of lightning was flashing directly overhead. It wasn't reaching the ground: the clouds were zapping themselves. This was a good time to take some pictures. I set the camera to take long exposures, and aimed it up at the sky. Unfortunately, the lightning flashed at all the wrong times, and when it didn't, it was almost invisible or was at the edge of the picture. I didn't get anything good until the storm died down.

I later learned that many thousands of people's property was damaged during the storm - not only from the hail, but also from tornadoes. There were at least 20 in Colorado that day. And I never even saw a single one.


Tuesday, May 29, 2012

The May 2012 Solar Eclipse


May 20, 2012 was a day for which I'd been waiting for more than 2 years. I had never seen a solar eclipse before, and this one would be visible from right where I lived - who could ask for anything better than that?

I didn't worry about how to view the eclipse until the day before the event. Up until then, I thought I could view it through a telescope with a solar filter, or maybe with a pair of eclipse glasses - but on the night before the event I still had nothing, and it was too late to get anything shipped from Amazon on time. I had to come up with another plan. I knew I'd definitely be able to view it with a pinhole projector (a fancy name for a board with a tiny hole in it), but I knew from experience the image of the sun would be either small or faint. I wanted something better. I couldn't use my dad's telescope to project the image; the first time I tried that, I ended up melting the lens from the powerful focused rays. I started thinking of how I could use lenses to project light onto a white surface. Then I realized that my toy 1.25" refracting telescope I'd had since I was about 5 would project the sun's image wonderfully. My refractor lets in so little light you can hardly feel the rays of the sun focused on your finger, so melting plastic wouldn't be a problem. If things worked well, that telescope would be what I'd use.