Acadeca Science Section 2: Circuits

Who was the Joule named after?

James Joule, a teenager during the industrial revolution

Who quantified Joule’s idea’s?

William Johnson, known as Lord Kelvin

What were Joule’s idea’s quantified into?

The Laws Of Thermodynamics

Kinetic Energy

The energy something has when it is moving

One thing is always true about Energy 

The total number of joules in a closed system never changes

Heat

Energy in transit between objects that are at different temperatures

A substance…contain heat, it only…or…heat

does not, emits or absorbs

Heat transfer always moves from

Hot to cold

Temperature

The average kinetic energy of the atoms in a substance

Atoms in any substance are…

constantly in motion

Usually, atoms in substances at…, on average,…

higher temperatures, move faster

Entropy

The amount of energy in a system that is unavailable to do work

Gravitational Potential Energy

The energy that an object possesses due to its position in a gravitational field

Is potential energy associated with the force of friction?

No, there is none

Electric potential energy

The energy associated with an objects position in an electric field

Voltage

The force that pushes electric current through a circuit

Electric potential

Electric potential energy divided by the charge directly proportional to the charged object

Electric potential is measured in

Volts

Electric potential is a description of

the environment around a particular object

Energy gain is given by

Delta E = W X H

Change in electric potential energy is given by

Delta E = q X V

Volt is named after

Alessandro Volta

Alessandro Volta is credited with inventing

the closest thing to a modern battery

When and who did the origin of the battery start with?

The 1780s with Lucia and Luigi Galvani

When the Galvani’s did their frog experiment, what did they theorize?

The movement was from the electricity inside the frog

Volta disagreed with their theory and said it was from the metals

True

Who was Giovani Aldini and what did he discover?

A nephew of the galvani’s, the left hemisphere of the brain controls the right side of the body

What does a modern disposable battery made out of

Carbon rod, Zinc rod, Sulfuric acid

What are modern disposable batteries called?

Primary batteries

What are secondary cells?

Batteries that can be recharged

While charging, what happens in secondary cells?

The terminals are switched and the lithium ions move to the other side

What is a circuit?

A closed loop that allows electricity to continually flow

What happens in a circuit?

When one area becomes negatively charged, protons in the circuit rush to neutralize that charge

Direct current

A current that always flows in the same direction

How do we quantify electric current?

Measuring the amount of charge that flows past a point per second

Current is measured in

Amperes

What were amperes named after?

Andre-Marie Ampere

What is a potentially fatal current to a human?

0.070 amps

What does an EKG device measure?

Voltage versus time

Ohms Law

I=V/R

Resistance and what is it measured in

Resists the flow of current, measured in Ohms

Conductive materials have…, and insulating materials have…

low resistance, high resistance

Voltage is more dangerous than Current

False, Current is more dangerous

Power

The rate of energy change over time

What is power measured in

Watts

When you flip a switch, what essentially happens?

It switches on an electric field to accelerate electrons

Substances with… have…

High temp, greater resistance (and vice versa)

What is the purpose of a resistor

To resist current by taking away energy from the flow of charge

If a switch is closed…

Current is running through it

If a switch is open…

the circuit is broken and there is no current

What are the 2 ways to connect resistors

Series and Parallel

If 2 resistors are in a series…

It is called a series circuit. The same current runs through both of the resistors

There is greater resistance and less current in a series circuit

True, greater resistance

When 2 resistors are parallel…

Its called a parallel circuit. The current has 2 options of where to go

If 2 resistors in a parallel circuit have the same resistance…

the same amount of current flows both ways

If 2 resistors in a parallel circuit have different resistance…

more current will flow through the resistor with the lower resistance

In a parallel circuit, total resistance is

decreased when you add more resistance (opposite of a series circuit)