Tag Archives: Physics

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

The Coolest Molecules

CAUTION: This experiment uses dry ice (-109˚F) and liquid nitrogen (-321˚F). Proper safety equipment should always be used when handling these substances.

Physics tells us that pressure, volume and temperature are all linked when talking about gases. So what does this have to do with solid carbon dioxide (dry ice) and liquid nitrogen? When dry ice is placed into a balloon at room temperature, which is then tied off, it will start to warm up.

molecules

Since the ambient air temperature is roughly 65˚F, the air that surrounds the balloon is more than 150 degrees warmer than the dry ice! This hug difference adds energy to the dry ice turning it into gaseous carbon dioxide through the process of sublimation. Sublimation is the phase transition of a substance directly from the solid to the gas phase without passing through the intermediate liquid phase.

molecules cool

Now that there is a balloon full of carbon dioxide gas we can cool it down with something colder than dry ice. This is where liquid nitrogen comes in. The balloon gets dunked into a bowl full of the -321˚F liquid! Cooling the gas in the balloon down means that it loses energy making the molecules start to clump, making the balloon lose volume. It will turn the carbon dioxide gas back into a solid through the process of deposition. Deposition is basically the opposite of sublimation, turning the gas directly into a solid.

molecules done

This process of cooling and warming to change the balloon’s volume can be repeated over and over again. Or, with the inflated balloon, dunk it in the bowl of liquid nitrogen, take it out, and before it can expand again, rip it open to see the solid carbon dioxide for yourself!

Written By: Mimi Garai

 

Free Energy or Toy

Electricity is one of the most useful discoveries of our relatively recent history. It lights the rooms we hang out in, give power to some vehicles and allows for communication across vast distances. In 1800, Italian physicist Alessandro Volta discovered that particular chemical reactions could produce electricity so he constructed the voltaic pile (an early electric battery) that produced a steady electric current.

energy

Since then, electricity has been adapted to try to fit the needs of people better. In 1891, inventor Nikola Tesla wanted to make a way to transmit electricity without the use of wires, so that more people could have access to a cities source. He created the Tesla coil, a resonant transformer circuit to try to do just that.

However, with this new technology came challenges. It turns out that spraying electricity into the air is a waste. Whether the power would be used or not, it’ll eventually dissipate. It is also quite dangerous without the use of proper equipment. The large arcs of electricity that you see are about 650,000 volts! For comparison, the electricity that comes out of your wall is at about 120 volts, which is dangerous in it’s own right.

energy zoom

Today, Tesla coils are not used for free energy, or really anything useful. However, they are used far and wide in classrooms as scientific demonstrations! They are also, really fun to play with, as long as you do so safely. Faraday cages or grounding rods should always be used, and can even be used to control the flow of the electric discharge!

Written By: Mimi Garai

Pendulum Waves

You’ve already seen the way a no-flinch pendulum works, so now we are changing it up. This contraption is host to many pendulums next to each other but not touching. When you raise them up and let them go all at once, you can see something truly mesmerizing.

pendulum wave

They will all start to fall at the same rate, thanks to the laws of gravity, but after the first swing the will not be synchronized. This is due to them being uncoupled, or not connected, and to the length of each individual pendulum. The pendulum furthest away has the shortest length and the closest pendulum has the longest. All of the pendulums in the middle gradually become longer as they get closer.

The period of a pendulum is mostly dependent on its length. Since the lengths gradually increase, so will the periods, causing them to become out of sync. However, that can cause some pretty visually pleasing effects!

pendulum wave middle

Of course, given enough time, all of our pendulums will eventually line back up again in the end. But not before going through some other awesome patterns, as well as what may look like chaos.

pendulum wave end

This is not the easiest DIY project, but it is possible to recreate, so give it a try. Or you can always find it online or in store, but either way it is definitely worth seeing in person. Let us know what you think!

Written By: Mimi Garai

To Infinity Table and Beyond

Light, it’s properties, and the ways it can be manipulated are as fascinating as they are beautiful. It can be bent, slowed down, absorbed, and reflected. It turns out that the study of optics looks into all of these different interactions. But what happens when you want to mix the science of optics with a bit of real-world fun? You get an infinity table!

Infinity tables are named as such due to the illusion that the lights go on forever down into the depths of the table. But how can that be?

Infinity Table

To answer this, you not only need to know how the table was made, but also what optical properties those materials have. The three materials that makes these tables unique are LED lights, a normal mirror, and a two way mirror. The LEDs of course provide the visually pleasing light source. The normal mirror on the bottom of the table allows for the light to be completed reflected back up. And finally, the two way mirror allows for half of the light to escape the box of the table, and the other half to be reflected back down.

Because half of the light can escape through the two way mirror, with each bounce, half of the light is lost from the box. This is how the light appears to grow dimmer as you look down further into the apparent depths of the table.

Infinity Table 1

These tables are not the easiest to make at home, however it is not impossible. A simple home goods store may have all of the supplies needed. Just be sure to have adult help and supervision if you are to attempt this, given that glass is involved.

Written By: Mimi Garai

DIY Eggshell Geodes

Geodes, seemingly ordinary rocks hiding pockets of crystals inside, have fascinated amateur geologists for centuries, but did you know you can make your own geodes with just what’s in your kitchen?

diy geodes

Materials:
Eggs
Something to hold the eggs (a piece of the carton works well for this)
Water-soluble solid (salt, sugar, baking soda, etc.)
Food coloring
Water
Saucepan
Heat-resistant container

diy geodes 2

Process:
Crack eggs as close to the narrow end as possible to save as much shell as you can
Heat water to nearly boiling and pour it into the egg, cooking the membrane inside so you can remove it. (if you don’t remove the membrane, it will mold and turn the crystals black)
Bring your water to a boil in the saucepan, gradually adding about half as much salt by volume as you have water
Keep adding salt until no more dissolves into the water
Add the mixture to your eggshells
Add the food coloring to each egg
Wait a few days for the water dissolve
Admire your results

So how does this exactly work? When you’re boiling the water, you’re adding energy to it in the form of heat, allowing it to dissolve more of the solid than it normally would. At this point, there’s so much solid (in our case salt) dissolved in it that there’s nearly no space left between molecules. This now “super-saturated” solution gradually loses energy as it cools down, forcing the solid out of solution slowly. This slow release allows the solid to instead build a growing network of crystals inside and outside the eggshell. This is actually a similar process to how geodes form in nature: water with dissolved minerals seeps into air pockets inside rocks, slowly depositing the minerals as the water flows through the rock. Try it for yourself!

Light: Just Flip It and Look You Will See

It is no surprise that we experience and use scientific phenomenons every day. But, did you know that our eyes do that too? At camp, we have a science experiment that demonstrates how our eyes take in light. This hole in the wall is a great model for an eye. Your eye has a few major components: cornea, lens, iris, pupil, retina, and macula, to name a few. For our purposes, let us focus on the iris and pupil. The pupil in an eye is basically just a hole. The iris is a muscle that can expand and contract to change the size of the pupil. The purpose of the pupil is to allow light to enter your eye.

light

light eyeLight, on Earth’s scale, travels in straight lines. So how does any of that light ever make it into your eyes for you to see the world around you? The key is reflection. Light bounces off of objects, and if it bounces just right, that information will make it all the way to you. However, the only light you will ever see are the rays that make it all the way through those tiny holes.

So why is the image that is formed upside down? Due to light traveling in straight lines, when the light that bounces off of someone’s head, that same information makes it through the hole. Any other reflection of light will slam into the wall, unable to pass along the data. Same thing goes for light bouncing off of someone’s feet. Because the light is entering through the small hole, it must intersect and thus the image is inverted. However, we don’t see the world upside down. Our brains have adapted to this phenomenon, and flips the images automatically! Our brains are amazing!

light more

Written By: Mimi Garai

Effortless DIY Electric Train

The relationship between electricity and magnetism is as old as space and time, but is a complicated one. As light propagates, electricity and magnetism flow in and out of each other, forever connected. This connection can allow for some pretty interesting phenomenons in physics.

DIY trainDue to induction, we can get the “train” to propel forward.  Induction is the act or process by which an electric or magnetic effect is produced in an electrical conductor or magnetizable body when it is exposed to the influence or variation of a field of force. This means that moving electricity induces magnetism, and moving magnets induces electricity.

DIY train 1Our “train” is composed of a battery and two strong magnets whose fields are repelling each others. It’s track is a long solenoid, or tightly coiled copper wire. The battery sends a current through the solenoid, which creates a magnetic field. That induced magnetic field then interacts with the magnets, repelling one magnet (pushing it) and attracting the other (pulling it). This push from one end and pull from the other creates a net forward motion (or if it is the exact opposite, then it will bounce out of the track due to a net backward motion).

If the two magnets are aligned with the battery such that their fields are attracted to one another, then there will be a net of zero movement. This is due to the induced magnetic field pulling the magnets in opposing directions. But, don’t take my word for it, give it a try for yourself!

DIY train gif

Written by: Mimi Garai

DIY Polar Opposites

Oil and water won’t mix no matter how hard you try. They have different densities and different polarities. But what happens when you mix oil and milk?

Milk is an emulsion. It is made of mostly water with lipids throughout. Lipids are organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents.

DIY Opposites

DIY oppositeWater is a “polar” molecule, meaning that there is an uneven distribution of electron density. Water has a partial negative charge (-) near the oxygen atom due the unshared pairs of electrons, and partial positive charges (+) near the hydrogen atoms. Due to the polarity, the attractive forces are very strong in water molecules. Oil is nonpolar, which means the attractive forces are pretty neutral.

diy spinning

Any liquid, to be able to mix with another needs to have nearly equal amounts of attractive forces among the molecules of both liquids. When you add oil to a bowl of milk something bizarre and amazing happens. You will see hundred of spheres form. The spheres are drops of milk which are surrounded by a layer of oil. These are technically bubbles!

But these bubbles are pretty hard to pop. You can even stir them and see how they move through the layer of oil! Give it a try for yourself.

Written by: Mimi Garai

 

DIY Limestone Caves

Most stone is made over millions of years, cooked in the core of our planet. That stone then erodes over time due to wind, acids found in rain and groundwater, and other natural weatherings. Chalk is a type of limestone formed by the shells of microscopic marine organisms.

diy caves

The process of erosion can produce beautiful features in earth’s crust, like arches, stacks, and caves. This process usually takes tens of thousands of years.

But we can make a limestone cave in just a matter of minutes. All you need for this DIY chalk cave is a block of chalk and vinegar.

cave diy

2CH3CO2H(aq) + CaCO3(s) > 2Ca(CH3CO2)2(aq) + CO2(g) + H2O(l)

cave diy crazy

The vinegar, a weak acid, reacts with the calcium compound, dissolving it. It then forms carbon dioxide gas, water, and an aqueous calcium solution. This same process takes place for real caves, but the acid in rain and ground water is much more diluted, therefore taking much much longer to see the results.

diy cave pic

Written by: Mimi Garai

 

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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