14Forms of Energy Mechanical Energy Ex: wind, water falling over a water fall, sound
15Forms of EnergyThermal EnergyEx: stove, heaters, matches
16Transfer of Heat- REVIEW Conduction- pot on the stoveConvection- hot air rises cold air sinksRadiation- from the sunReflection- heat bouncing offHeat energy is caused by the motion of particles that make up matter. When you rub your hands together, you are converting mechanical energy into heat energy.
36Review Questions Name 3 things that are insulators. List 3 things that are conductors.What is the difference between an open and closed circuit?What is the difference between a series and a parallel circuit?What type of metal attracts other metals?
41Answers to Trivia Questions Can sound travel under the water? Yes sound can travel under the water. It moves four times faster through water than through the air. It can travel such long distances that whales can hear each other when they are nearly a hundred miles apart.Is there sound on the moon? No, there is no sound in space. Sound needs something to travel through like air or water.What is the speed of Sound? Sound travels through air at 1,120 feet (340 meters) per second.
49Force The greater the force, the greater the change in motion. The bigger an object is, the less effect a force will have on it.The smaller an object is, the more effect a force will have on it.
50How do things move? Above Below Ahead Behind Up Down Horizontally VerticallyRightLeft
51FrictionFriction is a force that opposes motion. Friction acts in a direction opposite to the object's direction in motion. Without friction, the object would continue to move at a constant speed forever.
52What Really Happened with the Apple? Probably the more correct version of the story is that Newton, upon observing an apple fall from a tree, began to think along the following lines: The apple is accelerated, since itsGravity is the attractive force between all objects in the universe. It is the force that pulls objects to the earth.
53Galileo, a famous Italian scientist who lived in the 1500's, was the first to discover the force of gravity. In his famous experiment he dropped two cannonballs, one 10 times the mass of the other, at exactly the same time from the Leaning Tower of Pisa. Which cannonball do you think hit first? Before you answer the question set up your own Galilean type experiment. Explanation: Both objects should hit the ground at the same time. Even though the two objects had different masses, gravity pulls each down to the ground at the same rate. Galileo discovered that gravity accelerates all objects at the same rate
54MagnetismSIX things to know about magnetsAlmost everyone knows these six basic facts about how magnets behave:A magnet has two ends called poles, one of which is called a north pole or north-seeking pole, while the other is called a south pole or south-seeking pole.The north pole of one magnet attracts the south pole of a second magnet, while the north pole of one magnet repels the other magnet's north pole. So we have the common saying: like poles repel, unlike poles attract.
55A magnet creates an invisible area of magnetism all around it called a magnetic field. The north pole of a magnet points roughly toward Earth's north pole and vice-versa. That's because Earth itself contains magnetic materials and behaves like a gigantic magnet.If you cut a bar magnet in half, it's a bit like cutting an earthworm in half! You get two brand new, smaller magnets, each with its own north and south pole.If you run a magnet a few times over an unmagnetized piece of a magnetic material (such as an iron nail), you can convert it into a magnet as well. This is called magnetization.
59Balanced and Unbalanced Forces F12-F13 A book resting on a desk illustrates balanced forces. However, a book dropped from a desk illustrates unbalanced forces. In this case, gravity has overcome the balance of forces
67On the weather channel a hurricane's path is explained in terms of velocity. People want to know how fast a hurricane is traveling but they also need to know in what direction it is traveling so they can evacuate if necessary. For instance, the weatherman will report a hurricane's velocity as five kilometers per hour moving in a northeasterly direction.
68Acceleration is the rate of change in velocity Acceleration is the rate of change in velocity. A roller coaster is constantly changing its velocity as it travels up and down and around. To calculate the acceleration of a roller coaster, divide the change in velocity by the time it takes the velocity to change.
69Momentum How hard it is to slow or stop an object in motion.
70Review An object’s speed in a particular direction An object slows down, speeds up, turnsAn object’s place or locationA measure of the distance an object movesA measure of how hard it is to stop an object
72BuoyantProcedure 1. Make a boat of some type out of your foil paper. 2. Put your boat into the container of water and begin to place marbles in one at a time (See Rule # 2) 3. Place your marbles evenly throughout your boat. Make sure you balance your weight evenly.Rules 1. You only have one attempt. You may not start over once you begin placing marbles in the boat. 2. You must wait three seconds before you can place another marble in your boat. 3. When your boat sinks, count the number of marbles in your sunken boat.
73Conclusion 1. In what way does the size of the boats make a difference in the amount of marbles they hold? Please be specific.2. In what way does the design of the boats make a difference in the amount of marbles they hold? Please be specific.3. Please describe which design held the most marbles and why.4. What would you do different next time?
74Newton's first law of motion says that an object in motion will stay in motion and an object at rest will stay at rest unless acted on by an unbalanced force. In the car your body was in motion, traveling at the same speed as the car. When the car stopped, your body stayed in motion. If you were not wearing a seatbelt and you were traveling very fast, your body could continue to move forward through the windshield!
75Inertia Inertia keeps an object still or keeps it moving. A moving object will keep moving until something stops it.An object that is not moving will not move until something moves it.
76If a bowling ball and a soccer ball were both dropped at the same time from the roof of a tall building, which would hit the ground with a greater force? Common sense tells us that the bowling ball would. We know that gravity accelerates all objects at the same rate, so both balls would hit the ground at the same time. Therefore the difference in forces would be caused by the different masses of the balls.
77A speeding bullet and a slow moving train both have tremendous force A speeding bullet and a slow moving train both have tremendous force. The force of the bullet can be attributed to its incredible acceleration while the force of the train comes from its great mass.
78Imagine a rocket is being launched from the earth Imagine a rocket is being launched from the earth. Hot gases are pushed out from the bottom of the rocket as the rocket is thrust upward. The force of the gases pushing against the surface of the earth is equal and opposite to the force with which the rocket moves upward. The motion of the rocket can be explained by Newton's third law, for every action there is an equal and opposite reaction. In other words, when one object exerts a force on another object, the second object exerts a force of equal strength in the opposite direction on the first object. Likewise, when a skeet shooter fires his shotgun at a clay disc flying through the air, he experiences the recoil upon the shotgun. The "kick" felt by the shooter is the reaction force upon the shotgun which is equal in magnitude to the force that pushes the pellets.