Tag Archives: Science

3D Printing an Asteroid

NASA has always been about accomplishing crazy. In the 1960s, the idea of people walking around on the moon was ludicrous, but NASA got them there anyways. Now, NASA is performing another crazy feat: sending a probe to an asteroid, collecting rock samples, and returning that probe to Earth. Additionally, the probe has created a digital map of the asteroid which we can recreate, simply by using a 3D printer.

OSIRISREx - 3D Printing Asteroid

In September 2016, the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer space probe (OSIRIS-REx for short) was launched aboard an Atlas V rocket. It quickly made its way into space and began its journey towards the asteroid designated 101955 Bennu. This journey lasted over two years as the robe used low-power thrusters and gravity assists from Earth to reach its destination.

Side by Side - 3D Printing Asteroid

Side by Side – 3D Printing Asteroid

OSIRIS-REx reached Bennu in December of 2018, and as it approached, it used its long-range PolyCam sensors to map out the surface of the asteroid. After arriving, OSIRIS-REx used its short-range cameras to take even higher resolution images of Bennu’s surface. NASA scientists used that data to create 3D models and released them to the public!

Rotation - 3D Printing Asteroid

Since we’re lucky enough to have a number of 3D printers here at camp, we decided to print our very own Bennu asteroid! You can see the results below, but if you want to have your own version of the asteroid, you can find the files at https://www.asteroidmission.org/updated-bennu-shape-model-3d-files/

Written By: Scott Yarbrough

Busting the Misconception Between Gravity and Atmospheric Pressure

A common misconception we see at AstroCamp is how gravity and atmospheric pressure work. It makes sense! The two seem interchangeable at a glance, however they both get weaker as altitude increases, and there can’t even be an atmosphere without gravity. Despite their similarities, the two are very different.

Gravity is a property of anything with mass. It’s one of the four fundamental forces in the universe, and it’s caused by an object bending spacetime around itself. The larger the object, the greater a force it will exert.

Pressure isn’t even a force (technically). It’s a measurement of how much force is being applied per unit area. A lot of force can be spread out over a large surface area so that the pressure is overall small, and a small force can be focused onto a small enough point to cause a high pressure.

When talking about atmospheric pressure, we’re talking about the average force per unit area the gas molecules are exerting on objects in the air. The air molecules are zooming everywhere and bouncing into everything. Every time they impact, they push with a tiny force.

Atmospheric pressure changes with 1) the rate of collisions and 2) the force of impact. More molecules mean more collisions, which leads to a higher air pressure. Similarly, heavier gases or gases moving at higher speeds will cause a higher impact force, also increasing the atmospheric pressure.

Air at sea level is being compressed by all of the air above it, weighing it down and increasing its density. When you increase altitude, the less air you have above you, so pressure goes down. This is why atmospheric pressure gets weaker the higher in altitude you go.

After learning how they both work, it’s easy to see why the effects of gravity and atmospheric pressure can get confused. But their differences are also prevalent enough that you should be able distinguish between the two!

Written By: Scott Yarbrough

Homopolar Motorcar

A homopolar motor is a device that relies on flowing electricity, magnetic fields, and the interaction between the two. It consists of a voltage source, neodymium magnets, and a conductor that allows electricity to flow. And it’s super easy to make yourself!

What you’ll need:

  • 1 AA battery
  • 2 neodymium magnets
  • Thick copper wire

 

————

Step 1

Place one of your magnets onto the positive terminal of the battery.

Holompolar Motorcar Step 1

Step 2

Use the already attached magnet to test the poles of the second magnet. Figure out which sides are repelling each other, and place the second magnet so that the repelling side faces away from the battery. This way, either both South poles or both North poles are facing outwards! (Note: it doesn’t matter which, as long as they’re consistent with each other!)

Holompolar Motorcar Step 2

Step 3

Shape your copper wire so that it can hook easily on the inside of the magnets. Try to maximize the amount of contact it has with the magnets on BOTH sides, so as much electricity as possible can flow. When it’s been properly shaped, hook the wire onto the motor!

Holompolar Motorcar Step 3

Instead of using a wire, you could use a sheet of aluminum foil! Lay it as flat as you can on a level surface, away from any metals that might attract your magnets. Make sure there are no tears or holes in the aluminum. Then place your battery-magnet motor on top! The aluminum will allow electricity to flow!

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When a magnetic field is applied to an object carrying electricity, it applies a force to that object. This is called the Lorentz Force. Due to the electricity flowing through the magnets, this force becomes a torque, causing the motor to rotate and drive forward!

Homopolar Motorcar Rollin

Written By: Scott Yarbrough

For Mimi by Twin Musicom is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/)

Artist: http://www.twinmusicom.org/

What is Jacob’s Ladder?

If you’ve taken our Electricity and Magnetism class, you’ve seen this device before! You press a button and an electric arc rises to the top of two tall wires. This is the Jacob’s Ladder! But what’s happening here? 

Jacob's Ladder

The base of the Ladder is a transformer — a device that changes an incoming voltage. In the Ladder’s case, it increases it by a huge amount. That voltage is put into one of the vertical wires, increasing its electric potential. The electricity needs to flow somewhere, so it ionizes the air to jump to the other vertical wire. As the electricity arcs, it heats up the ionized air, which causes it to rise. As the wire get further apart, it becomes more and more difficult for the electricity to reach, and the arc eventually stops. Then the transformer builds up the electric potential again, repeating the process all over again. Though as electricity flows through the wires, they heat up. The hotter they are, the slower the electricity flows. Eventually, you’ll notice the arc having trouble getting to the top as it travels slower and slower.

Jacob's Ladder 2

This is just one of the many cool electricity demos we have at AstroCamp! Be sure to check out this and all the others on your trip.

Written By: Scott Yarbrough

 

Asteroid to Meteorite to Crater

Every day, about 40 tons of space rocks reach the top of Earth’s atmosphere. These asteroids come in many different sizes and have been floating around in space for billions of years. Once they reach the Earth, however, they become meteors — more colloquially known as shooting stars.

Meteorite 1

Friction with the air causes the rock to ignite and luminesce. Most of these are pretty dim and can only be seen at night. And most of these are also too small for any chunk to reach the surface of the Earth; the heat and friction vaporize the meteors completely. However, sometimes the meteor is large enough to withstand the friction until it hits the surface. These are classified as meteorites. Very few of these are large enough to leave a significant impact, but every once in a while, a large meteorite touches down. When this happens, it compresses the surface, which will decompress moments later as a shockwave, traveling through the rock and carving out a crater.

Meteorite 2

Very rarely, an extinction-level event meteor collides with our planet. Such an event happened 66 million years ago, and is a possible cause of the major extinction event that killed all the dinosaurs. The impact is hypothesized to be a billion time stronger than the first atomic bombs, sending ash and dust into the air that blocked sunlight for more than a full year.

Meteorite

Thankfully, such events are incredibly rare, so the most you’ll have to be worried about is a small dent in your car — and even that is unlikely to happen!

Written By: Scott Yarbrough

What is a Tippe Top and How Does it Work?

At first glance, a Tippe Top looks like a normal spinning top. A few moments after you spin it however, the tippe top flips over and begins spinning on its thin stem, raising its center of mass upwards! This marvel of a toy stumped physicists and was popular among many well-known figures in the mid-1900s.

tippe top

The strange mechanics that add potential energy to the toy fascinated Nobel Prize winners Niels Bohr and Wolfgang Pauli. It was originally designed in the mid-1800s, but was reinvented in the 1950s and sold as a toy. Very popular at the time, it drew the attention of physicists who sought to figure out exactly what was happening.

tippe top physics

In order to flip over and raise its center of mass, the tippe top needs to translate some of its rotational momentum. It does so because its center of mass is actually lower than its geometrical center. As it spins, the rotational axis is offset from the point of contact with the table, which causes the top to trace out a circle on the table.

tippe top  gif

The friction with the table applies a torque that causes the top to tip over, changing its angular momentum. When it becomes horizontal, the top actually reverses its direction of spin! Once the stem hits the table, the torque causes the top to flip over! It’s spinning slower than it was before, and that energy has gone into gravitational potential energy!

It just goes to show that even simple-looking toys can have some cool and challenging physics behind them! You just have to stop and think about how they actually work.

Written By: Scott Yarbrough

Pendulums and Gravity

In the video above, I talk about how pendulums actually work. If you haven’t watched it, the principle is simple: an object is suspended from a fixed point and allowed to swing back and forth – the mass of the object and the time it takes to swing back and forth are independent of each other, relying only on the length of the string and the strength of gravity.

Normally, you’d think of gravity on Earth’s surface as being constant, but the Earth isn’t a perfect sphere, meaning that the force of gravity near the equator is slightly weaker than at higher or lower latitudes. And how did we discover this fact? Pendulums!

Pendulum and Gravity 1

In the year 1671, a French scientist named Jean Richer travelled to French Guiana. Among several experiments and astronomical observations during his two-year trip was to take measurements with a clock pendulum.

He set up the pendulum in the same way I did in my video, but he adjusted the length of the pendulum so that one half-swing took exactly one second, a common technique at the time. What he found was that the pendulum length needed to be slightly shorter than it did back in Paris, by about 3 millimeters. Though a small difference, it was significant enough to begin a discussion about the varying gravitational field of Earth.

Pendulum and Gravity 2

This was later proved by Isaac Newton by determining that due to the Earth’s rotation, it was thicker at the equator, meaning the surface was further away from Earth’s center of mass. This was further supported by Newton’s idea that gravitational force decreases as the distance between two objects increases.

Scientists started to use pendulums to take measurements of the gravitational field in other locations and began to create a model of the Earth’s true oblong shape. Since then, we’ve developed more accurate methods to measure the same thing, but they were pioneered by those first efforts.

Written By: Scott Yarbrough

Video Music: Funky Chunk Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

http://creativecommons.org/licenses/by/3.0/

Happy Earth Day!

Today is Earth Day! We spend this day celebrating Earth, raising awareness of things threatening the planet, and learning how to fix those problems! This year’s theme is plastic pollution and the threat it poses to humans and other life.

Plastics can be very useful, but the huge amount that is discarded incorrectly and dangerously is a serious issue. In one year alone, the state of New York uses enough plastic bags that, if they were tied together, they could reach the moon and back – 18 times! Worldwide, about 1 trillion bags are used and disposed of every year. And that’s not including other plastic items like drinking straws, plastic bottles, and single-use plastic containers.

earth day 18Much of what we use is not disposed of correctly! Each year, about 8 trillion tons of plastic waste ends up in our oceans. The waste congregates together, forming enormous “islands” of floating plastic where fish and other sea life cannot live. There are currently 5 of these huge clumps around the world – the largest of these is the size of Texas! If the current trend of littering continues, there will be more plastic by weight in the ocean than fish by the year 2050.

All this means, however, is that we have a long way to go to fixing this problem. And you can help out, too! Here are some steps that you can follow to start:

  • earth dayReduce! Minimize your use of plastics, because recycling is far from perfect, and many recycled plastics will end up in landfills anyways.
  • Refuse! Similar to reduce, but making a more conscious effort to reject using plastic products, such as not taking a straw at a restaurant.
  • Reuse! If you do use plastic products, be sure to avoid single-use items and instead choose something that you can continue to utilize over a longer period of time; or better yet, get yourself reusable, non-plastic items.
  • Recycle! When you do end up using and needing to dispose of plastic products, recycle them! But be smart about it. Only recycle products that you know are recyclable. Educate yourself on local recycling management procedures and what kinds of material they take.
  • Remove! Help to clean up the plastic that is already littering our planet! Helping can be anything from picking up trash yourself to supporting organizations that are tackling the problem at a larger level.

All in all, there is a lot to do, but education is the first step to solving these issues. Tell a friend or a family member what they can do to help! Let’s work together to make the world a better place.

If you want to learn even more about what to do or how to help, here’s the link to the official Earth Day 2018 website: https://www.earthday.org/

Written by Scott Yarbrough

Supernovas!

Believe it or not, supernovas have been known to humans for thousands of years. That’s not to say that ancient civilizations knew exactly what was happening when they saw them, but they were witnesses to some of the most powerful events in our universe. When certain stars reach the end of their lifetime, they explode in a spectacular way. These stars are most commonly very large, anywhere from a few times as massive as our sun to a few hundred times as large. These supernovas emit an incredible amount of light, the brightest of which can be billions of times more luminous than our sun.Supernovas

However, these explosions occur fairly rarely. Scientists believe that only a handful happen in the Milky Way every thousand years. But when they do, they are bright enough to be seen from Earth. In the year 1054, Chinese astronomers observed a new star near the constellation of Taurus. It quickly grew, until it appeared even brighter than the planets in our solar system. This visitor star lasted for about two years, eventually dimming until it could no longer be seen.

Supernovas 1In the 1700s, astronomer John Bevis discovered the Crab Nebula in the Taurus constellation, and it was later recorded by Charles Messier as the first object in his 110-object catalogue. Two hundred years later in 1928, another astronomer named Edwin Hubble connected the records of the Chinese astronomers and the object known as the Crab Nebula to be the same thing, separated by almost a thousand years. His theory was that the nebula was the remnants of a supernova, which was the source of the visitor star.

This turned out to be correct, and later it was determined that at the center of the nebula was a pulsar – a very quickly spinning neutron star left over by the explosion. This revelation led to the discovery of dozens of other supernova remnants. Over the past few decades, research into supernovas has greatly expanded our knowledge of astronomy and stellar evolution. We haven’t seen a supernova in our galaxy for a long time, and we’re due one in the near future. Astronomers have identified several stellar candidates that may explode sometime soon – and when one of them does, we’ll get to experience another visitor star for the first time in hundreds of years.

Written by Scott Yarbrough

Bernoulli’s Principle

Daniel Bernoulli was a Swiss mathematician and physicist in the mid-1700s. He excelled in the fields of statistics and probability, but also was influential in applying mathematics to physical mechanics. Particularly, he is known for his work in fluid dynamics, now known as Bernoulli’s Principle.

bernoulliMost simply, Bernoulli’s Principle is a derivation of the conservation of energy. The sum of all the energies in a steady flow of a fluid (a gas or a liquid) must remain constant. So, if the fluid is forced to move faster, it creates an area of low pressure to compensate.

This principle may seem simple, but it led to the development of two very important machines in the 1900s: the carburetor and the airplane.

The carburetor is the precursor to modern automobile and aircraft engines. Using Bernoulli’s Principle to control the flow of fuel and air, it allowed automobiles and airplanes to control their speed and acceleration with relatively high precision. More efficient methods have since been designed, but without the basis of Bernoulli’s Principle, these machines would never have been developed in the first place.

bernoulli 1Additionally, Bernoulli’s Principle is critical in the design of airplane wings and allowing them to generate lift. The bottom of the wing is flat, while the top part is rounded. As the wing cuts through the air, the gas going over the top has a longer path to take, which requires it to move faster than the air underneath the wing. This creates a low pressure area on the top of the wing. The pressure difference between the top and bottom causes an upwards force to be exerted on the wing, allowing the airplane to fly. While this is not the only source of lift, it is an important factor that allows airplanes to work the way that they do!

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!

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