Week of March 23

Magnetism!

Big Idea: Forces between objects act when the objects are in direct contact or when not touching.

I can...

• Build and electromagnet to investigate magnetic properties and fields
• Explain how generators and motors produce their own magnetic field when an electric current flows through it

Vocabulary:  magnet, magnetic force, magnetic pole, magnetic field, electromagnetism, solenoid, electromagnet, electric motor, electric, generator, electromagnetic induction

Magnetic Force - feel the push and pull!

What makes some materials magnetic and some not magnetic?

•  Iron, nickel, and cobalt are the top 3 materials that have magnetic properties
• Materials are magnetic due to spinning electric charges 
• Magnetic force can act at a distance - just like gravity and electrostatic force
• Magnet have poles - a north pole and a south pole
• Unlike poles attract - like poles repel

Magnetic Field - the area surrounding a magnet

Magnetic charge flows from north to south; the magnetic force is strongest at the poles

The Earth is a Magnet!

The Earth's Magnetic Field

What does our magnetic field have to do with auroras?

What is going on inside magnetic materials?

• Whether a material is magnetic or not depends on the type of atom the material is made of
• As an electron moves around an atom, it makes an magnetic field - in substances like iron - a north and south pole are created
• In a substance like copper, the magnetic fields cancel each other out and therefore it is not magnetic
• In substances like iron, nickel, and cobalt, the north and south poles form areas called domains
• If the domains can line up, then the material can be become magnetic or be temporarily magnetized

Types of Magnets

 1.  Ferromagnets - these are materials that can be turned into magnets

2.  Temporary Magnets

• Some materials can be magnetized for a short period of time - the domains line and it becomes a magnet

3.  Electromagnets

• Electromagnets use an electric current to create a strong magnetic field that can be turned off and on
• Electromagnets are used to pick up heavy materials like scrap in a junkyard

• Electromagnetism results when an electric current and magnetic field interact
• When a magnetic field creates an electric current in a wire it is called electromagnetic induction
• Electromagnets are used in motors

• Electric generators use induction to change mechanical energy to electrical energy

How an electric generator works

Links:

Magnet Game

Bill Nye Magnetism

The Auroras

Magnetism and Electromagnets

Maglev Trains

Junkyard Magnet

Magnet and Compass Interactive

Generator Interactive

Magnets and Electromagnets Interactive

Week of March 16

Welcome to a new topic!  It is a very charged one!  

Electric Charge and Static Electricity!  

Big Idea - Forces between objects act when the objects are in direct contact or when not touching

I can...

• Recognize that the electrical force increases as electrical charges increase
• Recognize that the electrical force decreases when the distance between the charges increases
• Given a simple interaction between 2 objects not touching, identify objects, interaction, and direction of force on objects

Vocabulary:  electric charge, static electricity, electrical 

conductor, electrical insulator, semiconductor, electrical field 

and force, induction, current

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What is electrical charge?

• Electrical charge is a property of matter!

• Electric charge involves electromagnetic interactions between particles of matter 
• Matter can be overall negatively, positively, or neutrally charged by the loss or gain of negative electrons
• Charged objects exert a force on each other even if they are not touching - this is called electric force
• How strongly the electric force pushes or pulls depends on the amount of charge and the distance between the objects
• Charging objects involves moving negative electrons from one object to another - but they are not lost - just moved
• Electric charge is always conserved - this means that the total amount of charges always remains the same - they just trade places 

• Objects with the same charge (like charges) - repel each each other
• Objects with different charges (unlike charges) - attract each other
• The closer the charged objects are, the stronger the electric force

How Do Objects Become Charged?

• Objects become charged when they gain or lose electrons
• This can happen 3 ways:  friction, contact, induction (charges are rearranged int he object without touching it)

What is Static Electricity?

You guessed it! The best example of static electricity is lightning!

Static Electricity is the build up of charges - lightning works likes this :

• During storms or windy conditions, negative charges (electrons) build up in the bottom of clouds due to friction mostly
• When enough negative charges build up, they induce or induction occurs and electric discharge happens in the form of lightning 

Conductor and Insulators

• Some materials are better conductors of electricity than others
• Most metals like copper are very good conductors - meaning they allow the charges to move freely 
• Other materials like plastics, rubber, and wood are not good conductors - but they are used to insulate metals that conduct electricity - this stops a lot of shocks and electrical fires!
• Semiconductors are a special type of conductor used in computer chips - their main material is silicon
• Semiconductors conduct electricity better than insulators but not as well as a material like copper - but they are perfect for usage in electronics 

Links:

Bill Nye Van de Graaff

Nat Geo Lightning

March 11-16

It's All About the Friction!

This rock stays in place due to static friction forces!

This polar bear slides over the ice due to kinetic (sliding)friction forces

Big Idea! - Forces have magnitude and direction

I can....

• Experiment with kinetic friction and drag by using an object that has limited friction

Vocabulary:  drag, kinetic friction, static friction, acceleration

Question 1:  Study the pictures below - which ones show examples of static friction and which ones show examples of kinetic friction    

 Example 1 

                                                                   

Example 2

 

                       Example 3

                                Example 4

Example 5

Links:

Air Track Gizmo 

The Science of Curling

A World Without Friction - MIT Video

Bill Nye Friction - video

Week of March 2

1.  Inertia is a Property of Matter!

Big Idea - Forces have magnitude and direction

I can...

• Investigate what happens to a stationary and a moving object when their net force = 0 and when their net force does not = 0 - and how this relates to the concept of inertia
• Recognize that free fall results from the gravitational attraction between the Earth and an object

Question 1 - Look at the picture below - explain how it relates to the concept of inertia.

2.  How Do Objects Move Under the Influence of Gravity?

Felix Baumgartner - on the edge of space!
Jump from Space! - video

Question 2 - On October 14, 2012, Felix Baumgartner became the first person to break the sound barrier and the record for highest sky dive jump.  He reached his maximum or terminal velocity - about 840 mph -  30 seconds after he jumped out of the capsule.  He was 24 miles above the Earth!

• What factors influenced his acceleration?
• What forces were at work as he fell back to Earth?
• Why do objects in free fall reach a terminal velocity - or stop accelerating?

Mass versus Weight

Question 3 - Use the picture above to explain the difference between mass and weight.

Question 4 - What 2 factors determine the force of gravity?

Question 5 - What 2 factors keep the planets in orbit around the Sun or satellites in orbit around the Earth?

Question 6 - What would happen if the Moon suddenly broke free of the Earth's gravity pull?

Links:

Bill Nye - Inertia is a Property of Matter - video

Tablecloth Trick - video

Asteroids Game - game to play 

Football and Newton's 1st Law - video

Gravity Trailer - video

Gravity Visualized - video

Water in O g - video

Feather and Hammer on the Moon - video

Solar System Planet Motion Animation

Space Junk 3D  - video