Tag Archives: Energy

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!

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

Electric Motor DIY

An electric motor is a device used to convert electrical energy to mechanical energy. Electric motors are extremely important in modern-day life. They are used in vacuum cleaners, dishwashers, computer printers, machine tools, cars, subway systems, sewage treatment plants, etc, and you can make your own at home! Here’s how:

Materials:

  • Copper wire
  • D battery
  • Magnet
  • Electrical tape
  • Scissors

electric diy

Step1:

Coil the wire around a battery about 30 times. Wrap the extended ends of the wire through the coil, securing the coils in place.

Step 2:

Carefully file the enamel off of the bottom half of the extended portion of the wire.

Step 3:

Secure one wire post to each end of the battery, creating a small U-shape to cradle the coil.

Step 4:

Slide a magnet onto the battery.

Step 5:

Place the coil onto the posts and give it an initial spin!

diy electric 2

Electricity will flow from the battery through the coil of wire. Moving electricity induces a magnetic field in the coil, which opposes the magnet half of the time, and is attracted the other half. Give it a flick and watch the electrical energy from the battery be converted into the mechanical spinning you see!

Written By: Mimi Garai

How to: Kinetic Sculpture

Kinetic sculptures are moving art pieces, that usually do not have a motor, but alternatively use other forms of energy to propel the movement. Wind, water, or an initial manual push are common types of energy which kinetic sculptures harness. The art piece that we are going to make is going to harness energy given off from a flame.

What you need:

  • Clothes Pin
  • Skewer
  • Construction Paper
  • Tea Candle
  • Scissors

kinetic sculptures

Step 1:

Cut a spiral in the piece of construction paper.

Step 2:

Secure your skewer with the clothes pin perpendicular to the table and lightly place the center of the spiral on the point.

Step 3:

Place the tea candle on the clothes pin, under the spiral, and light it.

kinetic sculptures 1

The flame heats up the air around it. Since hot air is less dense than cold air, it rises. The air current flowing pass the spiral will push it, causing it to spin. There you have it, an easy DIY kinetic sculpture, harnessing energy to make moving art. What awesome science-art pieces can you come up with?

Written by: Mimi Garai

Ready, Set, No Flinch Pendulum! Thats Science!

The conservation of energy tells us that a bowling ball won’t swing higher than the initial height if there is no force added. But should we still believe that in a high risk situation? We are putting the laws of physics up to the test.

Caution: Do not try this at home without parental supervision.

Sir Isaac Newton says the total energy an object has will alway stay the same, unless you do something to change it (push or pull it). The system will start with a certain amount of potential energy, the energy possessed by a body by virtue of its position relative to others. When you raise the bowling ball to face level you are putting energy into the system in the form of work. Work is done when a force is applied to an object and the object is moved through a distance.

pendulum

When you let go of the bowling ball and it starts to swing the ball will gain kinetic (or moving) energy, and lose it’s potential energy proportionally. This proportional loss and gain ensures the total energy of the system remains constant.

At the bottom of the pendulum (when the bowling ball is closest to the floor), all of the potential energy has been converted to kinetic energy. Therefore, the amount of kinetic energy in the ball is equal to the total energy of the system.

Pendulum science

On the upswing of the pendulum, the kinetic energy will start to convert back into potential energy. This will happen until it reaches your face, where there is no longer kinetic energy, but instead the potential energy is equal to the total energy.

This pattern of gain and loss of potential and kinetic energy would continue on and on in perfect conditions. However, here on Earth, there is no such thing as perfect. With each swing of the pendulum there is a little bit of energy lost due to friction in the rope. This loss of energy will dampen each swing, causing the maximum height of swing to go down each time.

science pendulum

This is a great way to test yourself to see if you trust in the laws of physics. Would you have to guts to face up to the no flinch pendulum?

 

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

Electric Lighter vs Mints: Crystalline Energy

Have you ever wondered what electric lighters and Wint-o-green Lifesavers have in common? No? Well we here at AstroCamp wondered exactly that and the answer is a surprising one: they both involve energy released from crystals!

Electric lighters like this piezo ignitor don’t use the normal flint and steel ignition method of a normal lighter, and they don’t have a gas reservoir. Instead, they use a spark produced from a piezoelectric crystal (a crystal that releases a small electric charge when compressed, warped, or otherwise physically manipulated) to light a stream of gas coming from a stovetop or grill. When you press the button, a hammer strikes the crystal, releasing an electric charge that travels along the lighter until it lights the gas.

However, a different process is happening within the mints: triboluminescence. When you bite into the Lifesaver, you break apart the sugar crystals, which release small amounts of ultraviolet light. Ordinarily, this would be unobservable, as our eyes can’t see UV light, but the wintergreen oil inside the mints fluoresces under UV light. As a result, whenever one of those small pops of UV light are released, the oil absorbs that light and re-emits it in the form of visible light. It may look like sparks are being released, but unlike the piezoelectric ignitor, no electricity is being produced.

The ides of energy released from crystals may seem like something out of science fiction, but grab some mints and see how real it is.

Bang, Pow! Collision Science

When cars, billiard balls, or football players collide, their momentum doesn’t just disappear. It has to go somewhere. Some collisional energy dissipates as heat, and some causes the incoming objects to recoil. Take a basketball hitting the ground. Both the ball and the ground become a little warmer than they were before. The basketball also deforms, storing elastic potential energy, which changes into kinetic energy as the ball pushes off and launches back into the air.

BounceBounce

When a ball hits the ground, its center of mass keeps moving down for as long as the ball’s elasticity allows. As a result, the ball is vertically squished for a moment before it bounces back up. Image credit: http://ej.iop.org/images/0143-0807/34/2/345/Full/ejp450030f2_online.jpg

The heavier a thing is, the more momentum it has in motion. Inertia depends on mass, too: the lighter an object is, the easier its motion is to change. When a bug hits a car windshield, the bug’s path changes dramatically, while the car is almost completely unaffected. The bug’s inertia and momentum are comparatively small, so the dynamics of the collision are dominated by the car’s movement. The same science applies when we drop a stack of bouncy balls of various sizes.

BallStack

At first, all three balls move together towards the ground. When the basketball makes contact, it stretches and deforms, then reverses direction, putting it on a collision course with the next object in the stack. The basketball is much more massive than its neighbor, so its motion dominates when they crash into each other. Unlike a bug and a windshield, however, the balls don’t stick together. Instead, the basketball’s momentum is transferred to the smaller ball.

SuperBounceTime

Momentum is directly related to both mass and velocity. If momentum is held constant, then when mass goes down, velocity goes up. The smaller, lighter ball is launched with impressive speed! Adding a third, even smaller component to the system compounds the effect.

The Pendulum Challenge

Think you could stand still with a bowling ball swinging towards your nose? It’s tough! This scary experiment is governed by the same principle that decides the dynamics of a car crash and guides trick shots on a pool table: a gigantically important physical law called conservation of energy. This law states that if a system is left alone, its total energy doesn’t change.

Pendulum1

A system’s total energy is composed of two parts: kinetic energy (the system’s motion) and potential energy (stored energy determined by the system’s position). Let’s think about our bowling ball when it’s suspended at head height. It’s not moving, so its kinetic energy is zero. We know that if we stop holding it up, it will fall. This means it has potential energy! this case, the potential energy comes from Earth’s gravity pulling on the bowling ball.

When we release the bowling ball, it begins to move. In other words, its potential energy starts turning into kinetic energy. This happens bit by bit: when the bowling ball has fallen a few inches, it’s not going very fast yet, and it still has most of its original gravitational potential. As it falls farther, more of its gravitational energy is converted to kinetic energy, so the ball picks up speed. The tradeoff continues smoothly and proportionally until all potential energy has been converted to kinetic energy. The bowling ball moves fastest (has highest kinetic energy) when it’s closest to the ground (has lowest gravitational potential energy).

Diagram

Credit: BBC

 

No physical system is perfectly efficient. Air resistance and stretch in the tether damp the swinging bowling ball’s momentum. A tiny bit of energy is dissipated with each turn of the pendulum until, finally, it comes to rest. Since each pass of the bowling ball carries less energy than the one before, the pendulum swings a little lower every time. As long as you drop the weight cleanly from your nose, it’s perfectly safe to stay put.

Pendulum2

It’s one thing to know that the bowling ball can never swing back up to its original height and crash into your nose… it’s quite another to override your body’s instinct to flinch or step back!

Experimenting with Hand Warmers: Its Hot

Your body knows that internal organs are more vital than, say, fingers and toes. In cold weather, it wouldn’t be very efficient to pump warm blood to the outside of your body, because then the heat could easily radiate away! Conserving warmth in your core is a great survival tactic, but it’s uncomfortable for the body parts that aren’t receiving as much circulation. Luckily, science has a solution! We’ve seen it before. We’ll see it again. It’s one of the most wildly useful concepts in chemistry! Let’s take another look at exothermic reactions.

HandWarmer1
Switching views between a regular and an infrared camera allows us to see the crystallization reaction in terms of both heat and visible light.

Reusable hand warmers are a great everyday example of exothermic behavior. These handy pocket heaters rely on liquid sodium acetate to produce warmth. The liquid is supersaturated– it’s on the verge of crystallizing. When we trigger a crystallization reaction, the sodium acetate changes from liquid (higher energy) to a crunchy near-solid (lower energy). The leftover energy has to go somewhere. It’s released as heat!

HandWarmer2

The rectangular mark you see here is invisible to the naked eye. The infrared camera, however, “sees” the warm area where the hand warmer contacted the skin!

Sodium acetate releases heat energy as it solidifies. To return a hand warmer to its original, liquid state, all we have to do is put the energy back. Submerge the used hand warmer in boiling water, and the added heat reverses the crystallization reaction! Energy-consuming reactions like this one are called endothermic. After boiling, the packet is back in its original higher-energy state, ready to start the process all over again the next time cold weather strikes.

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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