Monthly Archives: August 2017

Gravitational Lensing

gravityMost of us have experienced using a lens in some way, whether it was using glasses, cameras, or our favorite, telescopes. A lens is a piece of glass or other transparent substance with curved sides for concentrating or dispersing light rays. They have the ability to bend light! Did you know that gravity can bend light in the same way? We call this gravitational lensing; when a large massive object, like a blackhole or galaxy, passes in front of our view of a distant light source and a distant galaxy. It bends the distant light in different ways, sometimes creating two or more images or creating an Einstein ring, a complete ring of the image.

 

gravity 1

The glass shape at the bottom of the stem of a wine glass, and looking straight through the glass has almost exactly the same optical properties as a massive galaxy or blackhole!

When you pass the glass over a light source or picture, it distorts the light into an Einstein Ring. This is one way Astronomers know about dark matter! According to Einstein’s theory of general relativity, the presence of matter (energy density) can curve spacetime, and the path of a light ray will be deflected as a result.

gravity 2

Written by: Mimi Garai

Watch what happens: LED in Liquid Nitrogen

It wouldn’t be surprising if nitrogen was your favorite elements. N2 is the most common molecule found in our atmosphere, making up roughly 78% of it. But here at camp, we have a different reason for why it is one of our favorite things to have around. We have a ton of liquid Nitrogen on camp and love using it to freeze things. We wanted to see what would happen when an LED (Light Emitting Diode) was submerged in the -321˚F liquid.

It turns out that something pretty cool happens… it changes colors! But why would cooling it down, taking energy away from the LED allow the color to change in a more energetic direction?

LED

To answer that we need to know how LEDs work. They are two-lead semiconductor light sources that emit light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes on a positive or negative band within the device, releasing energy in the form of photons.

LED 1

When an atom is at rest it’s electrons are at the lowest energy state possible. With LEDs, an electron is shot in, hits another electron which increases its energy, hopping up to the opposite band. When it starts to rest enough, it falls, giving off a photon (light particle). The bigger the hop in energy state, the greater the fall will be, and therefore the more energetic the photon will be.

LED 3

The electrons start off with a bit of thermal energy, but when submerged in the liquid Nitrogen some of the thermal energy is removed. When the thermal energy is removed it allows the distance between the bands (the band gap) to physically increase which in turn will increase the fall of the electron, increasing the frequency of light!

Written by: Mimi Garai

Microwave Plasma

We go through our daily lives encountering three of the states of matter; solid, liquid, and gas; nearly every moment, but the fourth, plasma, is much rarer for most of us. Plasma can be found around most forms of visible electricity, like lightning, but you can find it inside your microwave if you follow the steps below. Before you get started, however, this experiment MUST be carried out with immense care and with an adult present; it is very easy to get this experiment wrong and deal damage to not only your microwave, but yourself as well.

For this experiment, you’ll need a microwave, a toothpick, a microwave-safe glass container, three discs of cork (or any material you can stick a toothpick into and use to prop up the glass, and a match. Place the four discs of cork in the microwave so that one is in the center and the other three are around it far enough for the glass container can rest on top of them. This is essential, as air needs to flow between the inside of the glass container and the inside of the microwave. Stick the toothpick into the center cork disc, and set the microwave to 20 seconds, but don’t run it yet.

microwave plasma

Light the toothpick and cover with the glass container, closing the door of the microwave and hitting start. You should see arcs of plasma coming from the lit toothpick and while it’s tempting to leave it go and watch for a while, only let it run for a few seconds. Otherwise, the glass will get too hot and could shatter, spreading broken glass through your microwave and removing the housing for the plasma, potentially lighting your microwave on fire. After you’ve shut off your microwave, let it sit closed for about a minute, allowing the glass to cool down, otherwise the sudden inrush of cool air from the outside could shatter the still hot glass.

microwave plasma 1

Those plasma arcs were cool, but how exactly did we make them? Well, plasma is essentially ionized gas, requiring either an increase in heat or adding more electromagnetic force, both of which are happening inside the microwave. When an object is burned, the fire is actually stripping away electrons, ionizing the atoms around the fire until the electrons get recaptured. Microwaves work by establishing a standing wave of electromagnetic fields, which push and pull the electrons stripped away from the fire. This causes them to collide with the air molecules inside the glass, adding heat to the air and stripping away more electrons. This continues until the air is ionized to the point of becoming plasma, dissipating, and then ionizing into plasma again. The reason we can actually see the plasma also comes down to those electrons, as their collisions with the air molecules can add energy to the air’s electrons, which then fall back into their normal energy levels and release light, similar to the effect of fluorescence we’ve mentioned in previous pieces.

If you want to make plasma yourself, get an adult and try it, but please remember to be careful.

3 Things You Need to Know About the Eclipse

You may have heard about the solar eclipse that will be happening on August 21st. For just a few minutes, the moon will be in front of the sun, blocking its light and casting a shadow over parts of the earth. What do you need to know about the solar eclipse?

  1. This is rare

Solar eclipses occur on the Earth about once every 18 months. That might actually sound pretty frequent, but there is also a lot of Earth. The shadow path from an eclipse is about 70 miles wide, so if you were to camp out in a lawn chair and wait from one eclipse to another, it would take (on average) about 360 years! This technique for observing this phenomenon is not recommended.

However, if you are captivated by the idea of seeing a solar eclipse, it doesn’t have to be a once in a lifetime event if you are willing to do some travelling. The motions of the earth and the moon are very predictable, so scientists have already figured out when (and where) eclipses will be for a very long time. The map below is an example of these predictions. As you can see, North America will see its next solar eclipse in 2024!

Eclipse    2. It’s not totally happening everywhere

This very much goes along with point number one. This particular eclipse will be sweeping the nation from Oregon to North Carolina. That path, known as the path of totality, is where the sun will appear to be completely covered but the moon. However, that doesn’t mean that if you are in another location like us, you’re totally out of luck.

Eclipse 1

Other areas will be experiencing a partial eclipse during this time. This awesome app will show you what you can expect from the eclipse in your location. At AstroCamp, we will definitely be checking out the eclipse even though we are almost 700 miles from the path. However, it’s important to have proper protections or techniques when viewing the eclipse, which brings us to point number 3.

The app linked above also has the time of the eclipse. At its longest, the eclipse will last 7 minutes, so don’t be late!

    3.  The dangers of staring at the sun

You have probably heard that it’s not a good idea to stare at the sun. As you have probably noticed, the sun is very bright. Having the moon block out half or more of the sun may seem like it makes it safe to look at, but it doesn’t!

Eclipse glasses are a piece of safety equipment used to view the sun. These glasses block out 99.997% of the light from the sun to make it comfortable and safe to view. Wearing these glasses around in a brightly lit room, the wearer literally can’t see anything. They are close to being complete blindfolds, until the sun comes into view. This cannot be emphasized enough: without these glasses, you should not be looking at the sun!

If you don’t have these glasses, you are not out of ways to view the eclipse. Through a very simple crafts project, you can view a projection of the eclipse on the ground or another screen. All it takes is getting a piece of paper (construction paper works well as its a bit sturdier) and poking a hole through the center. Then, by angling the paper towards the sun and looking at the small point of light in the center, you can view a projection of what is going on with the sun and the moon.

Here in Idyllwild, the sun will be 62% covered. However, due to the sun’s immense brightness, it won’t look dark outside. In fact, if you were to look at the sun (DON’T), it wouldn’t look any different. If you want to see what is happening with the sun, strangely, the best thing to do is look down. Try to find and look at the shadows from any small openings, like a hole made with your fingers, or those made from the leaves on a tree, you will notice something interesting: All of the shadows have little eclipses in them!

Eclipse 3

DIY Chemistry: Coca-Cola and Milk

Mixing different liquids together to see what they taste like seems like a part of human nature. But have you ever mixed your favorite drinks together just to see if a chemical reaction will occur? This is an experiment that you can easily DIY, but we do not recommend drinking it. All you need is a bottle of coke and a bit of whole milk.

chemistry 2

Pour the the milk into the full bottle of coke to top it off and then put the cap back on. Mix gently and then keep an eye on it for about an hour.

chemistry

There is a chemical reaction that occurs between the Phosphoric Acid in the coca-cola and the calcium in the milk.

3Ca + 2H3PO4 ///\\\ Ca3(PO4)2 + 3H2

The reaction creates a precipitate, or solid matter, that is more dense than the liquids, therefore sinking to the bottom of the bottle. This precipitate is mostly just milk that has curdled, or become a solid.

chemistry 5

Now that you have separated the liquid and precipitate, try mixing them back together. A simple way to do this is by simply removing the bottle cap. There was a build of pressure in the bottle due to the chemical reactions. Once the bottle cap is removed the change in pressure allows the mixture to recombine. Enjoy!

Written By: Mimi Garai

Freezing Liquid Nitrogen in a Solid

Liquid nitrogen is super cold, -320 degrees Fahrenheit, but what if we could cool it down further or even freeze it into nitrogen ice? Watch this video and read more to find out!

Freezing Nitrogen

The solution lies in a summer day at the pool, sweat, or at least something tying them: evaporative cooling. When you get out of a pool and the water evaporates off of you, it is actually taking heat away from you because evaporation is something called an endothermic process, or something that takes heat energy away from a system. That’s actually the entire point of sweating; your sweat evaporates, cooling your skin.

Now, liquid nitrogen boils and evaporates at room temperature, but that process is too slow to cool it enough to freeze. We need to use evaporative cooling to bring it down from -320 to -346 degrees Fahrenheit, which means we need a lot more evaporation in a shorter period of time. For this, we turn to our vacuum chamber.

Inside the vacuum chamber, air pressure is dropping to nearly zero, so the liquid nitrogen boils away faster due to the ideal gas law. When pressure of a system decreases but temperature remains the same, volume must increase; this means more liquid is transitioning to the higher-volume gas. As the liquid nitrogen boils away faster and faster, it cools down the remaining liquid nitrogen until it eventually reaches the freezing point of -346.

Freezing Nitrogen 1

This solid nitrogen can’t stay, however. Once we equalize pressure inside the vacuum chamber with the outside, it reverts back to its liquid state. This method of producing solid nitrogen is actually the primary way of creating it in laboratories here on Earth. Out in space, solid nitrogen can be found on the surface of Pluto and Triton, one of Neptune’s moons.

Freezing Nitrogen 2

Written by: Miles Hensley

The Cleaning Secret of Bleach


If you’ve ever done laundry, you know that bleach stains dark clothes and brightens light ones, but why does it do that? Well, the answer is all down to chemistry.

Bleach 1

Inside the dyes we use in clothes, food, etc., there are chemicals called chromophores. These chromophores reflect a specific wavelength of light, causing them to appear a certain color, like purple in the case of the water in our video.

Bleach

However, when bleach is added to the equation, it goes through a process called oxidation, releasing oxygen molecules. This oxygen reacts with the chromophores, breaking up the chemical bonds between them. With their bonds broken, the chromophores reflect less color, an altered color, or even a wavelength of light outside the visible spectrum depending on the type of dye in use. The reduced or invisible color reflection is just seen by our eyes as white, making light colors look lighter, and the stronger dyes like the dark purple water shift to another color, appearing as a bleach stain on our dark clothes.

 

An Egg and Fire

This experiment is very easy to do but will blow your mind. We have said time and time again that light can bend and reflect in crazy ways. Here is another example of that.

Just by charring the outside of a raw (or cooked) egg shell and dipping it in water, you will be able to see something crazy! The egg appears to turn silver. But when you lift it up out of the water again it goes back to black?

Egg

The carbon soot that builds up in the outside of the egg is a combination of multiple sized particles of carbon. Those particles trap air along the surface.

Eff

This air layer traps light that is traveling through the glass, water, and air, and causes total internal reflection to occur. Total internal reflection is when light enters a medium and is reflected back and forth at the boundary of the medium, in this case the water and air boundary.

WELCOME TO OUR ASTROCAMP BLOG

We would like to thank you for visiting our blog. AstroCamp is a hands-on physical science program with an emphasis on astronomy and space exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and astronomical happenings. This blog has been created by our staff who have at least a Bachelors Degree in Physics or Astronomy, however it is not uncommon for them to have a Masters Degree or PhD. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science, space and astronomy information. Feel free to leave comments, questions, or share our blog with others. Please visit www.astrocampschool.org for additional information. Happy Reading!

Categories

Archives

Tags