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La Luna, My Moon and its Phases

The moon, it is always there in the sky watching us. Its no wonder that stories have been weaved through our history that tell of the mystical powers of the moon. One of the oldest depictions of the of the moon is located not too far from here in Knowth. The central chamber of the burial mound is said to hold this nearly 5000 year old map of the moons surface. Those who have seen it say that it has pits and mountains representing the craters and mountains we can see on the moon with the naked eye. The rest of the burial mound is decorated with circular and spiral patterns, all believed to be various depictions of the moon.

The truth is however, that the moon is no more mystical then any rock in the forest. The moon isn’t like all the twinkling stars in the sky, it doesn’t shine bright, in fact it doesn’t shine at all. I’m not trying to say that the moon isn’t important to our everyday lives, it is responsible for the ocean tides, changing day lengths and the magnificent eclipses that make us stop in our tracks.

You might wonder how the moon was created, of course no one knows for sure. There are theories that it was created at the same time as the Earth as just extra material that was spun out of Earth’s gravitational field. However, the most widely accepted theory is that there was a massive impact from an object the size of Mars while the Earth was still forming. This impact threw debris into space, and as the Earth reformed the remaining material collected into what we know as the moon.

Did you know that we always see the same side of the moon? The moon’s rotational period, or lunar day, is exactly the same as the lunar orbital period, or the time it takes to go around the Earth once. The Moon is in a geosynchronous orbit meaning it is locked in the same orientation with the Earth.

The moon is the brightest object in the sky, second only to the sun, however if it weren’t for the sun we wouldn’t be able to see it at all. The surface of the moon is actually very dark and it doesn’t produce any of its own light. The dust on the moons surface is very similar in color to coal, however even this dark dust can reflect a small amount of light. The moon reflects most of its light directly back towards the sun. This reflection towards the sun is what causes phases of the moon. As the moon orbits around the Earth, the angle of the sun to the moon to the Earth changes. In the diagram below you can see all the phases of the moon.

There are two types of eclipses, solar and lunar. Lunar eclipses happen when the Earth’s shadow blocks the light from the sun during its full moon phase. Since the shadow of the Earth is larger than the viewing disk of the moon, the whole moon goes dark. A solar eclipse happens when the Moon passes into the path of the suns light to the Earth during the new moon phase. The Moons shadow is much smaller then light coming from the sun, so thats why a solar eclipse has a specific viewing area across the Earth’s surface.

Long ago, Chinese people used to think that solar eclipse was a dragon swallowing the sun. They would make noise by banging on drums and yelling to try and scare the dragon away. Of course solar eclipses are only temporary, so the sun would always return.

Want to create your own eclipse?

Materials:

tennis ball, ping pong ball, flashlight and a table with a table cloth

Procedure:

  1. Place the tennis ball about two feet away from the flashlight, and the ping pong ball in between at about the one foot point. 
  2. Make the room dark.
  3. Turn the flashlight on  and make sure its pointed at the tennis ball.
  4. Move the ping pong ball around and observe where the shadow falls.
  5. The tennis ball represents Earth, the ping pong ball represents the Moon, and the flashlight is the Sun.
  6. What happens when you place the Moon on the other side of the Earth?
  7. If you would like to observe the phases of the moon for yourself, slowly move the ping pong ball in a circle around the tennis ball and observe how the light from the flashlight looks on it.

Intervention 2011

I’ve been away for the last couple weeks, but I haven’t been sitting around doing nothing. I’ve been incredibly busy officially introducing myself to the world. Back in May I was asked by Onizumi Hartstein to help design a children’s programming track for an internet creators convention that she started in 2010, Intervention. I was all too willing to help out and agreed to take point on several science experiment sessions specifically designed for kids aged 4-12.

This year was the first year for a children’s programming track at Intervention, so there were no rules or expectations. We planned a number of crafts, contests, dance parties, games and experiments for kids.

Since this convention focused on internet creators, there was a large focus on web comics and their fan base. I decided to focus one of my experiment sessions on the science of art. I taught the kids to experiment with light and color. We taught them how colors are created on TV or computer screens, how colors are combined to create other colors, how to separate colors, the colors of elements and we played with LEDs.

I decided to turn our participants into spies for the second experiment session. They were able to learn about fingerprinting, using invisible ink and decoding messages. The kids seemed to really enjoy the experiments and each one of them seemed to learn something they didn’t already know.

Of course we had to end with a little bit of fun! We decided to let the kids get a bit messy and play with explosions. We taught them about the reactions between diet cola and Mentos, water and Alka Seltzer, and we had a foam fight with baking soda and vinegar. All in all a huge success!

I’ll be sharing all of the experiments over the next few days. So get ready to have fun with


 

LadyAstrid with con creator Onizumi Hartstein


Mobius Victrola

I’ve decided to return to my family home in Birr. I love wandering the halls and gardens. It helps me clear my head. Maybe I’ll be able to make a plan while I’m here. Father loved science too and he was always tinkering in his lab. Now, it is my lab.

This afternoon I went down to the lab to check its condition. Everything was covered with thick canvas blankets which were themselves covered with a thick layer of dust and grime. I guess that’s what happens when no one enters a room in more than four years.

The lab was magical. As I pulled away each blanket, I find my trove of treasures growing. Under one, a dissection table. Beneath another, a whole row of microscopes of varying sizes. Under another, a table full of photographic equipment. The lab seemed to go on forever with every instrument that you could imagine, including many household objects that Father had snuck down here to tinker with.

One of my favorite inventions of his was a Mobius Victrola Phonograph. He had read a paper by German mathematician August Ferdinand Mobius that discussed a one sided object that lived in three dimensions. Father had created a Mobius strip out of old acoustic ribbon and connected it to a Victrola using two spindles and a foot pump. I was always amazed at how the the music never stopped, never needing to be flipped.

 

How do you make a Mobius Strip?

All you need is some paper, tape, and a pair of scissors.

  • Cut out a long, thin, strip of paper.
  • Holding it the tall way label the top left corner “A,” the top right corner “B,” the bottom left corner “C,” and the bottom right corner “D.”
  • Give the strip a twist and tape the two ends together so that “A” touches “D” and “B” touches “C.”

Here is where it gets interesting! If you start drawing a line around the strip, you’ll end up right back where you started. See, it doesn’t have a front or a back! The top and the bottom are the same with the twist in the strip connecting what was the top to the bottom resulting in one big side.

Another interesting property of the Mobius strip is what happens when you cut it. Start cutting your strip down the middle, like you are cutting two, thinner strips. But you don’t get two! You end up with a much larger, and thinner, Mobius Strip.

The Power of Steam


 
I sometimes wonder if people on a train really understand what is getting them from one place to another. I wonder if they understand that the power behind this train is one of the most amazing forces we have harnessed and that in harnessing that power we have cause a technology revolution. Steam is such a simple concept yet so powerful.

I remember when I was little sitting in the kitchen with Mum making tea and playing with my brand new pinwheel that Father had brought home from one of his many trips to Dublin. It was pretty when it spun. I remember Father coming in and telling me he wanted to show me a secret. He had me stand up next to the stove and teapot with my pinwheel and he put the edge of the pinwheel into the stream of steam. The pinwheel began to spin very fast! Father explained that instead of blowing on the pinwheel to make it turn the steam was making it turn. He explained that the pinwheel was now steam powered and being able to control the hot steam was all that was different between that pinwheel and making the steam train move.

Want to make a steam powered can?

You will need to gather:

  • A can of soda
  • A nail
  • A bucket of water
  • A one yard length of string
  • A lighter or matches
  • A gas burner or candle

Be careful! Steam is very hot and you will need an adult to help you for this experiment.

What should you do?

  • Holding the can over the sink use the nail to make a small hole in the long side of the can. Make a similar hole in the opposite side of the can.
  • Drain all of the soft drink from the can.
  • Push the nail into one of the holes. Turn the nail to the right until it lies flat against the can. In this way, the metal of the can is twisted to create a hole facing to the right. Repeat this same action on the opposite hole, still turning the nail to the right.
  • Tie the string to the hole on the tab at the top of the can to allow the can to hang vertically when suspended by the string.
  • Hold the can on its side with one of the holes facing up and lower the can into the bucket of water. Push the can into the water and fill the can with water to a bit under the holes you created.
  • Remove the can from the bucket.
  • Hold the loose end of the string and hang the can over the candle. Use the lighter or matches to light the gas burner or candle and wait until the water boils and the can spins. This will take some time because water takes a while to boil.
  • Once you see the can spinning, turn off the gas burner or blow out the candle and place the can in the bucket of water or in a sink to allow it to cool.

What’s really happening?

The flame heats the water inside the can until eventually the water starts to boil. When water boils it changes from liquid water into steam. The steam inside the can builds up pressure and starts to push out through the holes in the side of the can. When the steam is moving fast enough out of the holes, it causes the can to move in the opposite direction and the can starts to spin.

Water exists in three states, solid (ice), liquid (water) and gas (steam). When enough heat is added to or removed from water it will change between these states. In this activity, heat is added to liquid water causing it to boil and evaporate to form gaseous water, commonly known as steam.

Steam takes up a lot more space, called volume, than liquid water because water molecules in steam are more widely dispersed. There is a lot of empty space between the water molecules in steam and those molecules contain more energy and move more rapidly than the molecules in liquid water.

As the water in the can turned into steam, the steam filled the can. The pressure inside the can increased as more and more steam was produced. The holes in the can were the only spaces through which the steam could escape. The holes were bent at an angle to direct the flow of the steam. According to Newton’s Third Law of Motion, every action has an equal and opposite reaction. When the steam pushed out of the can in one direction the can was pushed in the opposite direction, making the can spin.

The pressure created when water turns into steam can be harnessed to make something move. In the Industrial Revolution, early locomotives, steam-boats and factories were powered by steam. The ‘choo-choo’ sound associated with trains is made by steam-powered locomotives. When the exhaust valve of a steam-powered locomotive opened, it released the train’s steam exhaust under great pressure, making a ‘choo!’ sound.