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Luckily, this project doesn’t actually create a portal through space and time, but it does use a simple trick of light. With two mirrors that reflect and transmit light differently, the infinity mirror creates a series of ever-weakening illusory reflections. The mirror in the back of the infinity mirror is a full mirror that reflects, or bounces back, almost 100% of the light that strikes it. The panel at the front of the infinity mirror (with the reflective window film attached to it) can only reflect about half of the light that strikes it. The other half of light that strikes this partial mirror is transmitted, or passes through it.
When the LED lights turn on in-between the two mirrors, some of the light escapes through the front partial mirror and into your eye. The rest is bounced back off of the rear mirror, only to be halved again when it hits the partial mirror at the front. This cycle continues over and over again seemingly to infinity; however, because a percentage of light escapes with each and every cycle, the reflected images of the LEDs look a bit dimmer and dimmer than the one before. Eventually, there is too little light escaping the mirror for our eyes to detect it, and the rest of the ‘infinite’ images fade to darkness.
THE MORE YOU KNOW:
Partial mirrors or “one-way mirrors” are used by police investigators to monitor suspected criminals while they are being questioned. This half-mirrored panel actually transmits and reflects light equally in both directions. But the unique effect comes by having different light conditions in the two rooms on either side of the mirror; one room must be much brighter than the other for the illusion to work.
With lots of light filling the interrogation room, most of the light seen in the one-way mirror on this side is reflected back from within this room, and the very small amount of light transmitted through from the dark room is drowned out. Anyone standing in the bright room will observe a mirrored reflection.
With very little light in the dark observation room, most of the light seen in the one-way mirror is transmitted through the glass from the other room, and the very small amount of light reflected from within this room is drowned out. Anyone standing in the dark room observes a clear window into the other room.
GOING ONE STEP FURTHER:
Make your own infinity portal mirror, and let your scientific brilliance shine on and on and on and on and on and on and on… !!!
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Like every object around us, our bottle rocket follows three simple rules of physics. These rules were originally written down by a scientist named Isaac Newton over 300 years ago; and we call them Newton’s Laws of Motion because they describe how an object will move when a force (a push or a pull) acts upon it.
The First Law says that when an object has no forces acting upon it (like an empty water bottle sitting on a table) it will never move all on its own, but remain at rest (like when we pick up the bottle, or knock it over!). On the other hand, an object that is already moving will continue to move in a straight line until a force causes it to stop or change its direction (like how gravity, wind, or resistance from the air influences our bottle rocket’s flight).
The Second Law says that objects of higher mass (that is, heavier objects) require more force to get them to move than do smaller objects. In the case of our bottle rocket, the force that makes it blast off comes from a chemical reaction between the distilled vinegar and baking soda. This reaction is the same one that makes foamy lava in the well-known volcano experiment because it produces a lot of Carbon Dioxide gas bubbles. Since the Carbon Dioxide gas is contained within the bottle rocket, pressure will continue to build up until it is strong enough to actually push out the bottle stopper. But consider this: if we used a larger (heavier) bottle for our rocket experiment, but still had the same amount of pushing force from the Carbon Dioxide, would you expect the rocket to fly as high? Why not?
The Third Law says that for every force, there is another force of equal strength and in the opposite direction. In other words: For every action, there is an equal and opposite reaction. For our rocket’s flight, it is easy to see that there is a lot of action (force) pushing downward from the tail-end of our rocket. But it’s less easy to see that this same exhaust flow creates an upward push on the bottle itself, a reaction force that is called thrust. If we had not flipped the bottle upside-down before it blasted off, the exhaust would have escaped upward and our rocket would have actually flown down toward the ground!!!
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Around the 4th of July, some people like to launch fireworks from their backyard. These commercial fireworks are actually low-grade explosives that would be very dangerous if they exploded at ground level. That’s why fireworks are equipped with a solid-fuel combustion rocket to launch them high above the spectators before safely setting off the gunpowder mortar.
3…2…1…blast off for rocket science!!!
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Oil is a hydrophobic substance, which means that it does not mix with water. Without the help of certain chemicals to bind them together, oil and water molecules repel each other. Even if you vigorously stir them together, the oil and water will eventually separate back into distinct layers.
Vegetable oil will naturally float on top of the water because it is less dense than the water. This is also why oil spilled in the ocean will float on the surface of the sea. This also explains why it is a bad idea to spray water on a grease fire, because the water will sink under the oil and evaporate, launching steam-driven hot oil everywhere! This also explains why you were probably more than a little bit disappointed when you initially placed the bottle filled with vegetable oil on top of the water bottle. Nothing really happened because the oil was able to stably float above the water. But when the water bottle is inverted over the vegetable oil, then small droplets of water begin to sink downward through the oil, displacing equal drops of vegetable oil that float upward!
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Hourglasses are devices that can be used to measure the passage of time. Typically, hourglasses are made of two glass bulbs that are joined together at a very narrow neck. This construction allows grains of sand (or sometimes other types of materials) to trickle from one bulb to the other in a regulated flow. The rate at which the sand flows through an hourglass can be affected by a lot of factors, including: how much sand is in the hourglass, how wide the neck is, or even how large the grains of sand are!!! Hourglasses that are made by professionals are meticulously designed to last for a certain length of time.
Images of hourglasses have been spotted in art from ancient times. One of the earliest forms of an hourglass, called a clesydra or a water clock, was used in ancient Egypt during the 16th century BC! Modern hourglasses can use very innovative materials to keep track of time, including magnetic granules that make interesting sculptural creations as they interact with a magnet inside of the base!
GOING ONE STEP FURTHER:
Don’t wait another second, it’s time to make your own liquid hourglass!
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The most commonly accepted explanation for this experiment is a phenomenon called laminar flow. Laminar flow happens when a fluid moves in thin sheets or layers that glide alongside each other, but never actually mix together. As the inner container is rotated, the sticky (or viscous) fluid will begin to twist after it, one layer at a time. As the layers of dyed syrup remain separate within their original layers of syrup, the dots will appear to stretch and blend together; however, the layers of color are simply overlapping, giving the appearance of blending together! From the side, the overlapping layers of colors give the appearance of mixing together. But if you look downward into the gap between the two containers, you will actually see how the thin layers have rotated, but not actually mixed together!
When you rotate the inner glass in the other direction, the layers of fluid simply twist back until the layers of colored syrup all line up in their original formation.
When you turn on the kitchen faucet at home, you might notice a lot of ripples or bumps in the stream of water—maybe some water droplets even jump out of the stream! This is because the water is very likely moving in a turbulent flow. Turbulent flow is characterized by an uneven flow of liquid, causing small swirls and ripples within the stream.
There are special faucet attachments that can create a more stable Laminar Flow stream of water. These faucets produce very clear and glass-like water streams that are often used in decorative fountains and even in amusement park water displays!
Happy New Year, science friends! Just go with the (laminar) flow!
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Electric Motors are used in many different electronics today. They can be found in electric cars, planes, trains, elevators, kitchen blenders, ceiling fans, computer disk drives, electric toothbrushes, vacuum cleaners, washing machines, electric toys, and even in your cell phone to make it vibrate when a friend calls! In each of these cases, the motors use electrical energy to create mechanical energy that can be used to rotate, vibrate, or drive an object. The arm of the motor (called the Drive Shaft) spins around when the motor is connected to the battery by a closed circuit of wires. A circuit is a closed conductive path that allows electricity to flow from a power source (like our AA battery) to run an electric appliance. If any one of the wires comes undone or is unplugged, the circuit can no longer allow electricity to flow and the motor will not run.
Because we attached an unbalanced weight to the Drive Shaft, the spinning weight will cause the Scribble Bot to continuously tilt from one side to another, causing the Bot to jitter around and seem to move on its own. This motion is especially visible when we attach markers to the Bot.
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Motors come in many shapes, types, and sizes. An especially large and powerful electric motor is now responsible for driving the largest truck in the world! The GVW BelAZ 75710 is a Russian mining truck that weighs a whopping 800 tons (1,600,000 pounds) when it is fully loaded. The truck is so massive that it requires four giant electric motors to get it running!
On the other hand, Engineers at the Cockrell School of Engineering at the University of Texas have recently designed and built a type of “nanomotor” that is 500 times smaller than a grain of salt. The microscopic drive shafts can spin 300 times every second, making them faster than a jet engine! Scientists hope that these nanomotors can help to deliver medicine to precisely targeted parts of the human body.
GOING ONE STEP FURTHER:
Build your custom Bot, and start Scribbling!
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Dry Ice is the solid form of Carbon Dioxide (CO2), which we know as a gas at regular temperatures. Amazingly, Dry Ice can only remain solid in very cold temperatures (at least 109 degrees below zero!!!). At everyday room temperature, the Dry Ice does not melt into a liquid like water ice; instead, Dry Ice sublimates, which means that it turns directly from a solid into a gas!
The molecules that make up a solid material are much more densely (or tightly) packed together than the molecules of the same material in its gaseous form. When we place the solid carbon dioxide (the Dry Ice) into the deflated balloon, we are inserting a large amount of CO2 molecules that are very tightly packed together but don’t take up much room inside of the balloon. As the Dry Ice is warmed by the heat of your hands, the solid CO2 will sublimate into carbon dioxide gas. Although there is always the same number of molecules of carbon dioxide in the balloon, the gaseous CO2 takes up WAY more room (it has a greater volume). This causes the balloon to inflate from the inside!
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Why do the bubbles float inside the tank? The carbon dioxide (CO2) gas that is formed from the sublimation of the Dry Ice is actually heavier than your breath that is filling the bubbles. The lighter bubbles are buoyant (able to float) on the surface of the heavier CO2 gas layer—even though you cannot see the invisible carbon dioxide!
Why do the candles go out when you pour the tank-air over them? While the air inside of the tank will get a bit cooler due to the very cold Dry Ice, the temperature is actually not the reason why the candles are extinguished. Also, the air pouring from the container is definitely not moving fast enough to “blow out” the candles. Fire needs 3 things to burn: a source of heat for ignition, fuel to burn, and oxygen to feed the flame. When the dense carbon dioxide pours out of the pitcher, it acts much like an invisible liquid that pushes away the oxygen around the candle flames. Without its constant oxygen source, the fire quickly goes out.
Why does the mega-bubble grow without having to blow it up? Much like the Self-Inflating Balloon experiment, the sublimating Dry Ice becomes CO2 gas. The gas is far less dense than the Dry Ice, and takes up a lot more space. The bubble solution film acts as a stretchy lid that will contain the sublimating CO2 gas inside the bowl, but is still able to grow quite large as the expansive gas is pushes outward from inside. When the bubble finally bursts, the misty air flows downward because it is cooler and more dense than the air around it…and so it sinks!
THE MORE YOU KNOW
Since its discovery in 1835 by the French Inventory Adrien-Jean-Pierre Thilorier, Dry Ice has been used as a packing and preserving coolant. Because Dry Ice does not leave behind pools of liquid after it warms, it is much preferred over “wet ice” (frozen water) for the purpose of refrigerated commercial shipping.
When Dry Ice is added directly to a food product (like when making ice cream with CO2, freezing fruit, or carbonating a soda product), the carbon dioxide will react with water molecules in the food to create carbonic acid. This chemical gives the food a sour, acidic flavor, but can also add a very distinct fizz!
***Remember to ask an adult for assistance with these chilling Dry Ice experiments.***
And please use your new Freezing powers for Treats, and not for Tricks this Halloween!!!