2011-2012

Current electricity

When electrons move, they carry electrical energy from one place to another. This is called current electricityor an electric current. A lightning bolt is one example of an electric current, although it does not last very long. Electric currents are also involved in powering all the electrical appliances that you use, from washing machines to flashlights and from telephones to MP3 players. These electric currents last much longer.

Electric circuits

For an electric current to happen, there must be a circuit. A circuit is a closed path or loop around which an electric current flows. A circuit is usually made by linking electrical components together with pieces of wire cable. Thus, in a flashlight, there is a simple circuit with a switch, a lamp, and a battery linked together by a few short pieces of copper wire. When you turn the switch on, electricity flows around the circuit. If there is a break anywhere in the circuit, electricity cannot flow. If one of the wires is broken, for example, the lamp will not light. Similarly, if the switch is turned off, no electricity can flow. This is why a switch is sometimes called a circuit breaker.

You don't always need wires to make a circuit, however. There is a circuit formed between a storm cloud and the Earth by the air in between. Normally air does not conduct electricity. However, if there is a big enough electrical charge in the cloud, it can create charged particles in the air called ions(atoms that have lost gained some electrons). The ions work like an invisible cable linking the cloud above and the air below. Lightning flows through the air between the ions.

How electricity moves in a circuit

Materials such as copper metal that conduct electricity (allow it to flow freely) are called conductors. Materials that don't allow electricity to pass through them so readily, such as rubber and plastic, are called insulators. What makes copper a conductor and rubber an insulator?

A current of electricity is a steady flow of electrons. When electrons move from one place to another, round a circuit, they carry electrical energy from place to place like marching ants carrying leaves. Instead of carrying leaves, electrons carry a tiny amount of electric charge.

Electricity can travel through something when its structure allows electrons to move through it easily. Metals like copper have "free" electrons that are not bound tightly to their parent atoms. These electrons flow freely throughout the structure of copper and this is what enables an electric current to flow. In rubber, the electrons are more tightly bound. There are no "free" electrons and, as a result, electricity does not really flow through rubber at all. Conductors that let electricity flow freely are said to have a high conductanceand a low resistance; insulators that do not allow electricity to flow are the opposite: they have a low conductance and a high resistance.

For electricity to flow, there has to be something to push the electrons along. This is called an electromotive force (EMF). A battery or power outlet creates the electromotive force that makes a current of electrons flow. An electromotive force is better known as a voltage.

                     

 

 

Electromagnetism

Electricity and magnetism are closely related. You might have seen giant steel electromagnets working in a scrapyard. An electromagnet is a magnet that can be switched on and off with electricity. When the current flows, it works like a magnet; when the current stops, it goes back to being an ordinary, unmagnetized piece of steel. Scrapyard cranes pick up bits of metal junk by switching the magnet on. To release the junk, they switch the magnet off again.

*(source) http://www.explainthatstuff.com/electricity.html

 

Click the link below to HEAR Static Electricity!

Electricity___Optical_Noise__Electrical_Crackle_And_Interference.mp3

*www.sciencemadeesimple.com/static.html

4th Grade students switch focus from LIFE science to PHYSICAL science.  The first area students study is about STATIC ELECTRICITY.

You walk across the rug, reach for the doorknob and..........ZAP!!! You get a static shock. 

Or, you come inside from the cold, pull off your hat and......BOING!!! Static hair - that static electricity makes your hair stand straight out from your head. What is going on here? And why is static more of a problem in the winter?

To understand static electricity, we have to learn a little bit about the nature of matter. Or in other words, what is all the stuff around us made of? 

Enjoy some pictures that were taken of the students while completing an experiment about static electricity.

To read more about all the interesting aspects of ELECTRICITY- check out the rest of the webpage http://www.sciencemadesimple.com/static.html 

 

 

 

 

 

 

Current Electricity: Building circuits to light a bulb!

Click this LINK to read what NASA science for kids has to say about circuits!!

 

When you flip a light switch on and off, you are closing and opening a circuit. A circuit is the path that electricity follows. For electrons to travel (creating an electric current), the circuit must be closed. When you flip the light switch off, you are opening the circuit and the lights turn off. When you flip the switch on, the circuit it closed and the lights come on.

 

Let's take a closer look at circuits . . .

 

Here are common circuit parts along with how the part is drawn in a circuit diagram:

 

 Voltage source
 Conductor
 Load
 Switch

Series Circuits
A series circuit allows electrons to follow only one path. All of the electricity follows path #1. The loads in a series circuit must share the available voltage. In other words, each load in a series circuit will use up some portion of the voltage, leaving less for the next load in the circuit. This means that the light, heat, or sound given off by the device will be reduced.

*The Nasa Science Files: Kids: Dr.D's Lab:Circuits

 

 

 

 

 

 

 

 

Parallel Circuits
In parallel circuits, the electric current can follow more than one path to return to the source, so it splits up among all the available paths. In the diagram, some current follows path #1, while the remainder splits off from #1 and follows path #2. Across all the paths in a parallel circuit the voltage is the same, so each device will produce its full output. 

 

                                

 

 

One of the last areas of study in 4th grade Physical Science is Gravity and Forces on Earth.  We had a great video conference with NASA where students were able to ask questions about space and see pictures depicting microgravity.  Part of the lesson was to explain that astronauts also take animals and insects into space to view how microgravity affects thier life as well.  Click the spider below to connect with the NASA sight that will make your skin crawl- even in space!!

                                                         

 

                                            

                                                               
Wrapping up the Electricity Unit, students created thier OWN electronic game boards!!  They did a wonderful job.  Look at the pictures to see students testing out each others games! 

What they did to create these gameboards: They worked with a partner to create TWO questions per lesson.  They posted the question on one side of the board and possible answers on the other side.  Using thier what they learned about circuits, they linked the correct answer to each question.  With a battery, light bulb and a few wires, they were able to discover the correct answer by making the light glow!

 

 

Below are pictures of students creating an ELECTROMAGNET!!!

       


         

We have recently learned all about ELECTRICITY!! Enjoy some pictures of students creating a series circuit- you will get a JOLT from!
             

 

 

Here are some clips to get a student interested in the subject matter we will be learning! Enjoy!

Gravity: