Batteries Q&A

Q: What is a volt?
A: Unit of potential difference, measures the amount of work/unit of charge

Q: Describe what an anode is. Cathode?
A: Anode: Gives electrons to the cathode. Cathode: Receives electrons from the anode.

Q: What is the purpose of the electrolyte?
A: To separate the anode and cathode and allow for the electrons to flow through the battery

Q: How to batteries die? What makes a rechargeable battery different?
A: When there are no more electrons the anode can give. Rechargeable batteries are able to reverse this process.

Q: Which metals create the highest voltage?
A: A more reactive metal(anode) and a lesser reactive metal(cathode)

Q: How does a current differ from a volt?
A current is how fast the electrons move through the wire whereas the volt is how fast the electrons are initially pushed.

Q: Why must you need a wire for a battery to work?
A: You need something to connect the anode and cathode so the electrons can run freely.

Acids and Bases

Confused on how to remember acids and bases? Learn this catchy song to help!

Also, here are some things to remember about acids and bases:

Acid: a substance that given hydrogen ions in water (H+)

- 0-6 on the pH scale

-conducts electricity

-reacts with active metals to liberate hydrogen gas

-strong and weak acids

Base: a substance that produces hydroxide ions in water (OH-)

-conducts electricity

-8-14 on pH scale

Aluminum Foil in Copper ii Chloride

In the video above, and time lapse is shown of an experiment we performed in class.  By placing 1.25g of copper ii chloride in 40mL of water, we formed a solution. The copper and chlorine dissolved into the water because the molecule is an ionic bond. We knew it was an ionic bond because copper is a metal and chlorine is a non-metal. After the solution was formed, we placed a piece of aluminum into the beaker. The aluminum then begins to replace the copper in the solution, dissolving the aluminum, forming the copper solid at the bottom, and changing the solution into aluminum-chloride. This is called a single-replacement reaction. The pictures below can help give a better understanding of this.

Aluminum Foil in the Copper ii Chlroide (before and after)

  

Here you can see the different amounts of copper ii chloride in 40 mL of water and how the more copper ii chloride there is, the faster the aluminum replaces the copper.

Here is a single-replacement reaction formula. For our experiment, it would be Cu2Cl +  Al produces Cu2 + AlCl

When the aluminum(red) is placed in the copper ii chloride and water solution, the aluminum replaces the copper(green) because it is more reactive. This is called a single replacement reaction. The copper then forms a solid in the solution.

Here is what the solution looks like after completed. The copper has settled at the bottom and the aluminum has dissolved into the solution, forming aluminum-chloride 

Our reaction and a visual representation of what was happening with the atoms.

This is a before and after of what will happen to each solution. The bottom row shows the copper and aluminum reaction still replacing each other. The top rows shows the copper settled at the bottom and no more aluminum left.

Salt Crystals Presentation

Here is a presentation my friend and I gave on our successful making of salt crystals.

Thermal Energy & Energy Transfer

A Short Story on... Mechanical Energy

Emma loved science. Ever since she was a litte kid, she loved to invent new trinkets, or try out an imaginative experiment. One day, when she was five, she tied a string attached to a bowling ball (don't fret! The string was a super strong material she created just a year earlier) to an iron bar on her ceiling. Being the cute mischievous five-year-old she was, she had people come up to the bowling ball and she would pull it back towards their noses, telling them not to move. After letting it go, it would swing forward, then back, approaching the person again. She maniacally laughed each time the person flinched or moved, for she knew the bowling ball would not hit them.  As she grew older, she also grew more intelligent, until she became a roller coaster engineer. Emma wanted to create Earth's wildest coaster, without any chains. So, she started a contest in which anyone could submit a design of their dream roller coaster. However, no design would be doable, for people made ignorant mistakes, like having the tallest hill at the end of the ride, or three loops in a row, none having a clothoid shape. Sitting, there, she played with her Newton's Cradle, watching the first ball hit the second and the fifth swinging up. She wondered, How can people be so dull-witted? I might just have to enter my own contest..., which is exactly what Emma ended up doing. Her design was zany, adrenaline rushing, and utterly nerve-racking, but most definitely doable. She would call it, the Deathinator. All was going well on the project, and it was soon opening day. Excitedly, Emma was about to cut the ribbon, when all the sudden, the Earth collapsed in on its self! But of course, as Emma knew, energy can only be converted from one form to another, so her last thought was proudly, Maybe our planet will burst into a million asteroids and ---, but the rest, the universe may never know.

Q&A on Circular Motion

This is a Slow Motion video of how the water in the bucket is not spilling out because of centripetal force

Q: What is centripetal force?

A: Centripetal force is what we call a force that is perpendicular to motion. A centripetal force can be any force, gravity, tension, friction, but it must be perpendicular to the motion of the object.

Q: Why is centripetal force circular?

A: Centripetal force is circular because the force acting on the object is a continuous perpendicular force. If the force is not constantly being acted upon the object, then it the motion will not be circular.

Q: What are some examples of centripetal force?

A: A car uses centripetal force to turn: the friction of the tire on the ground causes the turn. Also, a swinging a ball on a string uses centripetal force because the string has a tension force, causing the ball to move in a circle.

Q: If you were to cut the string attached to the ball as it was moving, what would happen?

A: The ball would move in a straight line in the direction of the velocity because of inertia. Here's a picture that better explains it: 

Q: What is centripetal acceleration? 

A: For every unbalanced force, there is acceleration. Because centripetal force is not a balanced force, there is centripetal acceleration. Centripetal acceleration is in the same direction as the centripetal force, which is ALWAYS inward. To calculate centripetal acceleration, use this equation: 

Ta-da! Hope you now have a better understanding on centripetal force!