Today’s Warm-UP • Complete CRCT Warm-ups for today. • Distribute the handouts in your team folder
Today’s Warm-UP • A boat leaves the dock and travels west reaching a velocity of 6 meters/second after 3 seconds. What is the acceleration? • A. 0.5 m/s2 C. 6 m/s2 • B. 2 m/s2 D. 18 m/s2
Today’s Warm-UP • Which of the following distance vs. time graphs represent decreasing velocity? • Graph _____ B
Today’s Warm-UP • 13. Which of the following distance vs. time graphs represent constant velocity? • Graph _____ C
Today’s Warm-UP • 14. Which of the following velocity vs. time graphs above represents positive acceleration? • Graph ______ D
Today’s Warm-UP • 15. Which of the following velocity vs. time graphs above represents no acceleration? • Graph ______ F
Science Standard • S8P5. Students will recognize characteristics of gravity, electricity, and magnetism as major kinds of forces acting in nature. • Demonstratethe advantages and disadvantages of series and parallel circuits and how they transfer energy. • Investigate and explainthat electric currents and magnets can exert force on each other.
Essential Question Why are some substances magnetic and other substances are not?
Textbook reference: Chapter 19 Keys to Understanding Magnetism
Key Idea A magnet is an object that is surrounded by a magnetic field and that has the property of attracting iron.
The spinning electrons in every atom produce tiny magnetic fields. In most materials the fields of atoms point in random directions so the magnetic fields cancel each other out.
In some materials the magnetic fields of electrons align with one another. A cluster of atoms with magnetic fields lined up in the same way is known as a magnetic domain.
Record in your notes: How is a magnet made? For an object to be magnetic, most of its domains (tiny magnetic fields produced by spinning electrons) must be aligned in the same direction.
Before magnetization After magnetization
Record in your notes: 1. A pole is the area of a magnetic where the magnetic effect is the strongest. Every magnetic has two poles – often called the north and south pole.
Magnets can produce: • An attractive force (pulling) whenunlike magnetic polesattract • A repulsive force (pushing) when like magnetic polesrepel. • Sounds a lot like the Law of Charges!
Record in your notes: 2. Magnetic force is caused by a magnet attracting (pulling) or repelling (pushing) other magnets and some other materials (e.g. iron and steel)
Record in your notes: 3. A magnetic field is area around the magnetin which magnetic forces act; concentrated into a pattern of lines that extend from the magnet’s north pole to its south pole.
Record in your notes: 4. Magnetic energy results when an object is moved a distance by a magnetic force.
Record in your notes: 5. Two Kinds of magnets - a) Temporary - easy to magnetize and demagnetize easily b) Permanent - hard to magnetize or demagnetize
Key Idea A compass points to the Earth’s North Pole because the Earth acts like a giant magnet.
Earth’s magnetic poles are not exactly the same locations as the geographic poles (axis where the Earth spins).
A compass can be used to find directions because its needle lines up with the Earth’s magnetic poles.
Consider the following: What would happen to the magnetic properties of a bar magnetic if you cut it into two pieces?
Losing Magnetic Alignment by: a)Dropping a magnet or hitting it too hard b) Putting magnet in opposite field for too long c) Increasing the temperature
Key Idea An electromagnet is a coil of current-carrying wire that acts as a magnet that can be turned on and off.
Record in your notes When a solenoid is turned on, a magnetic field is created.
Record in your notes If a piece of iron or other ferromagnetic material is wrapped by the coils of wire in a solenoid, a magnet is created when the current is turned on.
Record in your notes • The strength of an electromagnet can be increased by: • Increasing the electric current in the solenoid • Increasing the number of coil loops around the ferromagnetic material • Using a stronger ferromagnetic material (more iron content)
Examples of Electromagnet Uses: • A doorbell or an alarm
Examples of Electromagnet Uses: • A doorbell or an alarm • Moving junk cars
Examples of Electromagnet Uses: • A doorbell or an alarm • Moving junk cars • Recording data on your computer • Reading the magnetic strip on the back of a credit card
Examples of Electromagnet Uses: • A doorbell or an alarm • Moving junk cars • Recording data on your computer • Reading the magnetic strip on the back of a credit card • Electric motors
Big Idea about Electricity and Magnetism Electromagnetism - interaction between electricity and magnetism
Big Idea about Electricity and Magnetism a. Magnetic forces arise from the movement of electrical charge. b. Electrical forces arise from the movement of a magnet (induced current)