DO NOW MONDAY Find your new assigned seat

DO NOW MONDAY • Find your new assigned seat. • Write one thing (or more) that you enjoyed most about your Christmas break.

• Today’s PLAN – To be prepared for second semester in 7 th Grade Science – To illustrate Mastery on first semester 7 th Grade Learning Targets • Today’s DO – We will review CLASS EXPECTATIONS – We will look at and retake semester test (if necessary) and/or do enrichment over first semester learning targets – We will prepare our binders for second semester

CLASS EXPECTATIONS 1) Be on time. 2) Be prepared for class before class begins. 3) Sit down and begin work on your DO NOW as soon as you enter the classroom. 4) Speak ONLY when given permission. 5) Get up out of your seat ONLY when given permission.

Enrichment Directions • Go to my teacher website from the BCMS homepage. • Click on the Magnetism and Electricity Online Games Folder. • Click on each link in that folder and complete the activities one at a time, STARTING AT THE BOTTOM (videos). The information in the videos and jeopardy games that you learn will help you with the other games at the top of the list.

Magnetism

What are magnets? • Let’s first start off with what causes an magnetic field… • A magnetic field is created around any moving charged object.

Magnetism • Magnetism is the force of attraction or repulsion between magnetic poles.

What is charged that is moving within an atom? • Electrons (e-) • The atoms within most materials have paired up electrons spinning in opposite directions so the magnetic field that is created by one is cancelled out by the other.

• Some materials like iron, nickel, and colbalt have a single electron or pair of electrons that spin in the same direction creating a magnetic field or a small atomic magnet.

The atomic sized magnets line up to create domains within the material. The individual domains line up to form a magnet.

A magnet has two ends called poles (dipoles), where the magnetic force is the strongest. • No matter how many times a magnet is broken, each piece always has a north pole and a south pole. • There is no such thing as a monopole.

A magnetic field exists around a magnet or any moving charged object. Magnetic fields are like electric fields or gravitational fields in that they allow magnets to interact without touching.

Rules for drawing magnetic field lines (same as an electric field): 1. Magnetic field lines always go from the north pole to the south pole (outside a magnet).

Rules for drawing magnetic field lines: 2. Magnetic field lines are closed loops and never cross or intersect.

Rules for drawing magnetic field lines: 3. Where the magnetic field lines are closer the magnetic field is stronger.

Draw magnetic flux lines around the magnets below: S N

Magnetic Field around the Earth

What we do know… The north magnetic pole and the geographic North Pole do not coincide. The magnetic pole is about 1500 km (930 mi) south of the geographic North Pole and it wanders. A compass actually indicates the direction of magnetic north, not true north. Therefore a navigator must need to know the magnetic declination for a specific area. This is the angular difference between magnetic and true north. The details and mechanisms of how and why the Earth has a magnetic field are unclear. They do believe that it may have something to do with motions in the liquid outer core.

Brainpop - Magnetism