Jan. 12, 2015 Chapter B2: Forces, Machines, and Work P B33 Identifying Cause and Effect Vocabulary 1. Cause- a person, thing, or event that makes something happen 2. Effect- the result of a cause; what happens Cause Effect You hit the baseball. The baseball changes directions. You pedal faster. Your bike moves faster. Lesson 1: What makes things move? Vocabulary 1. force- a push or a pull 2. friction- the force caused by two objects rubbing together that slows down or stops moving objects Notes • Objects cannot move unless a force is applied to them. • Force is needed to slow down, speed up, or change direction. • When you change the direction of force, you change the direction an object moves. • More force is required to move heavier objects or to move objects faster and farther. Jan. 13, 2015 Lesson 1: continued Notes • Friction occurs between two objects that are rubbing against each other. • Friction slows down or stops a moving object. • Rough objects, like a rug, produce more friction than smooth objects, like tile. • An object will continue moving until a force is applied, such as friction. • Without friction people would not be able to walk or put food on a fork. • Friction causes heat between the objects. Jan. 14, 2015 Lesson 2: What are gravity and magnetism? Vocabulary 1. gravity- the force that pulls objects toward the center of the earth 2. magnetism- the force that causes magnets to pull on objects that are made of certain metals, such as iron 3. pole- a place on a magnet where magnetism is strongest Notes • • • • Without gravity, objects would float away. Gravity pulls objects toward the earth. The pull of gravity gives objects weight. Weight is the measure of the pull of gravity on an object. That is why mass and weight are different. Jan. 15, 2015 Lesson 2: continued Notes • Magnets attract objects made of certain metals. The force is called magnetism. • Every magnet has a north and south pole. • Magnets are strongest at the poles. • North and south poles are on opposite sides on the magnet. They attract each other, which means they stick together. • When the same poles are near each other, they repel, or push away. • When a magnet is hanging on a string, its north pole will point north (like a compass). Jan. 20, 2015 Lesson 3: How do simple machines help you do work? p B44 Vocabulary 1. work- something done whenever a force moves an object through a distance 2. simple machine- one of six kinds of tools with few or no moving parts that make work easier 3. lever- a simple machine made of a bar or board that is supported underneath at the fulcrum 4. fulcrum- the point on which a lever is supported and moves 5. inclined plane- simple machine that is a flat surface with one end higher than the other 6. screw- a simple machine used to hold objects together 7. pulley- a simple machine made of a wheel and a rope 8. wheel and axle- a simple machine that has a center rod attached to a wheel 9. gear- a wheel with jagged edges like teeth 10. wedge- a simple machine used to cut or split an object Notes • Work is done anytime you use force to move an object. • The amount of work depends on how much force is needed(how big the object is) and how far the object moves. • Moving two puppies is more work than moving one. • Pushing a ball two feet is less work than pushing it ten feet. • If an object does not move, no work was done. For example pushing the wall is not doing work. Jan. 21, 2015 p B46 Lesson 3: continued Notes • Simple machines make work easier. There are 6 types. • A lever is made of a bar or board. It moves across a point called the fulcrum. • Levers help you move objects by pushing on one end. • If you move the fulcrum closer to the object, you can lift it more easily. • A seesaw is an example of a lever. • An inclined plane is made with a flat surface that is raised on one end. • Ramps are inclined planes. • A slide and a hill are examples of inclined planes. • A screw is an inclined plane wrapped around a rod. • Screws hold things together. Jan. 22, 2015 p B48 Lesson 3: continued Notes • A pulley is a rope or chain that is wrapped around a wheel. • A pulley helps to move objects up and down. • We use a pulley to raise the flag and raise blinds up or down. • A wheel and axle is made by a rod attached to a wheel. • A wheel and axle can help move heavy objects. • Skates, wheel on a car, and a wheelbarrow are all examples. • A gear is a type of wheel with teeth. • They can help things turn and move. • A watch and a bicycle both have gears. • A wedge is made of two inclined planes together. • A wedge can split things apart. • Knives and axes are examples of wedges. • Animals use parts of their bodies as simple machines. • A rabbit uses its claws as wedges and its hind feet as shovels, or levers, to dig through the dirt. • A bird uses its beak as two levers fastened together to pick things up. • Beavers use their long teeth as a wedge to cut wood.
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