Science STAAR Need to Know 1 STAAR Reporting Category 2 Force, Motion, & Energy Middle School Science Science STAAR Need to Know

2 Energy The ability to do work or to cause change

3Science STAAR Need to Know Chemical Energy – Energy transformations Chemical energy – when light energy from the sun is converted to the energy in the bonds of the sugar molecules formed in photosynthesis.

4Science STAAR Need to Know Chemical Energy Examples of chemical energy changing into heat energy: Lighting a match Burning a wood fire

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6 Electrical energy- Energy transformations Electrical energy- flow of electrons (a current) Other ways of generating electricity: Water flowing through a dam in a river to move turbines Wind generators that use the energy of moving wind & operate a generator Nuclear power plants convert atomic energy into heat. Heat boils water to form steam & then follows the same energy transformations as coal power plants666

7Science STAAR Need to Know Many energy transformations… Electrical to mechanical: Electricity used to spin the CD (Spinning CD has mechanical energy due to its position or motion) Electrical to sound: A laser converts the digital information on the CD into electrical energy and this energy goes to the headphones as a vibration- this transmits Sound! Chemical to electrical: Batteries store chemical compounds that react when they are used to power something. This produces a flow of electrons which is electricity!!

8Science STAAR Need to Know Sound energy- Energy transformations Sound – consists of mechanical energy waves created by vibrations. Sound must travel through something (called “medium” or “media”) such as air, water, or a solid. The medium carries the energy of the wave from one place to another. Example: Air transmits the energy of the vibrating material in the headphones to your eardrums. A vacuum is a space that contains little or no matter. Sound can’t travel through a vacuum since there are no particles to squeeze together (compression) or spread apart (rarefaction)

9Science STAAR Need to Know Light waves do not need a medium to transmit energy! They can even travel through empty space.

10Science STAAR Need to Know Water waves are a form of a wave that transmits mechanical energy across the surface of water. A wave is a disturbance that transfers energy from one place to another.

11Science STAAR Need to Know Seismic waves are caused by earthquakes that transmit mechanical energy through the Earth’s layers.

Energy Potential Energy The energy that results due to an object’s position Kinetic Energy The energy derived from an object’s motion When is kinetic energy converted to potential energy during a roller coaster ride? Science STAAR Need to Know Highest Potential Energy Highest Kinetic Energy

13Science STAAR Need to Know Potential (PE) Stored energy

14Science STAAR Need to Know Kinetic Energy (KE) Energy due to motion of an object Speed & mass affect kinetic energy– Faster/heavier…more Kinetic Energy Did you know that the gas burned in a car engine is chemical energy being turned into Kinetic Energy? Rubber band flying through the air has kinetic energy

15Science STAAR Need to Know Before the yo-yo begins its fall it has stored energy due to its position. At the top it has its maximum potential energy. As it starts to fall the potential energy begins to be changed into kinetic energy. At the bottom its potential energy has been converted into kinetic energy so that it now has its maximum kinetic energy A waterfall has both potential and kinetic energy. The water at the top of Bridal Veil Falls has stored potential energy. When the water begins to fall, its potential energy is changed into kinetic energy. This change in energy also happens at Niagara Falls where it is used to provide electricity from the transformation of mechanical and electromagnetic energy.

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17Science STAAR Need to Know Energy Transformations Potential energy A rock sitting at the top of a cliff Roller coaster car at the top peak of a hill A swimmer posed to dive off the end of a diving board NO MOTION !! Kinetic energy A bouncing ball A moving roller coaster A track star running A girl skiing MOTION is the key!!!!

Energy Conversions Name the energy conversions in each of the pictures to the right using the following terms: Solar Energy Mechanical Energy Sound Energy Chemical Energy Electrical Energy Light Energy Science STAAR Need to Know

Energy Conversions Name the energy conversions in each of the pictures to the right using the following terms: Solar Energy Mechanical Energy Sound Energy Chemical Energy Electrical Energy Light Energy Science STAAR Need to Know solar to electrical electrical to light wind to electrical electrical to sound chemical to electrical

20Science STAAR Need to Know Forces may MOVE objects Forces may transfer energy between objects

21Science STAAR Need to Know 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.

GRAVITY 22Science STAAR Need to Know

23Science STAAR Need to Know You use force to move your body When you bend your arm, your muscles contract, which applies force to your arm bones. Your arm responds to this force by moving. During breathing, muscles contract (use force) to move air in and out of the lungs. The heart contracts (uses force) to pump blood through the blood vessels, carrying oxygen to the muscles.

24Science STAAR Need to Know All living things use force to move Emerging seedlings exert force on the surrounding soil. This force pushes the stem of the plant out of the ground. Plants exert force to open flower petals, curl & uncurl leaves & push roots through the soil. Force is used to move materials in & out of cells. Fish exert force to swim by pushing against the water.

Forces Consider the forces acting on these books. Are the books moving? Are the forces balanced or unbalanced? Science STAAR Need to Know Gravity pulling downward Table pushing upward Air pressure

Forces Consider the forces acting on these books. Are the books moving? A: NO Are the forces balanced or unbalanced? A: BALANCED Science STAAR Need to Know Gravity pulling downward Table pushing upward Air pressure

Forces Balanced Forces - occurs when multiple forces acting on an objects does not cause an object to change its speed Unbalanced Forces - occurs when multiple forces acting on an object causes the object to increase or decrease speed Science STAAR Need to Know Identify if these items are examples of BALANCED or UNBALANCED forces. Constant speed

What is the net force acting on these objects? Will these objects change speed? Science STAAR Need to Know 15 N 25 N 3 N 1 N 2 N

What is the net force acting on these objects? Will these objects change speed? © Hedgehog Learning 15 N 25 N 3 N 1 N 2 N NET: 10 N Down NET: 2 N Forward

30Science STAAR Need to Know In order for a force to move something, it must be an unbalanced force. This means that a force is stronger in one direction than the forces in the opposite direction.

Balanced & Unbalanced Forces 31Science STAAR Need to Know

Speed 32Science STAAR Need to Know

Velocity 33Science STAAR Need to Know

Speed – the distance an object travels in a certain amount of time Velocity – the speed and direction of an object Acceleration – a change in velocity An airplane flies from Dallas to Boston, a distance of 1500 miles, in 4 hours. Describe the flight of the airplane in terms of average speed and velocity. When does the airplane accelerate?

Science STAAR Need to Know Speed – the distance an object travels in a certain amount of time Velocity – the speed and direction of an object Acceleration – a change in velocity Average Speed: 375 miles/hour Velocity: 375 miles/hour to the northeast Positive acceleration occurs at takeoff; Negative acceleration occurs at landing

36Science STAAR Need to Know Data can be displayed & interpreted in many ways

ACCELERATION 37Science STAAR Need to Know

38Science STAAR Need to Know Force & motion are related

NEWTON’S 1 ST LAW OF MOTION 39Science STAAR Need to Know

NEWTON’S 2 ND LAW OF MOTION 40Science STAAR Need to Know

NEWTON’S 3 RD LAW OF MOTION 41Science STAAR Need to Know

#3 – every action has an equal and opposite reaction #1 – an object will only change speed if acted on by an unbalanced force - Law of Inertia #2 – the acceleration of an object is related to the its mass and the force acting on it F=ma

Identify which law of motion is being represented. Science STAAR Need to Know A moving red billiard ball hits the side bumper on the table and bounces backward at nearly the same speed. An airbag inflates to help cushion to rapid deceleration of the people inside the car during an accident. A powerful rocket engine producing more force is used on a more massive rocket to produce the same acceleration.

Identify which law of motion is being represented. Science STAAR Need to Know A moving red billiard ball hits the side bumper on the table and bounces backward at nearly the same speed. - 3 rd Law of Motion An airbag inflates to help cushion to rapid deceleration of the people inside the car during an accident. - 1 st Law of Motion A powerful rocket engine producing more force is used on a more massive rocket to produce the same acceleration. - 2 nd Law of Motion

Work 45Science STAAR Need to Know

Work – the energy needed to move an object over a certain distance The woman had to pick up a box with a mass of 5 kg and lift it a distance of 2 meters. How much work did she do? Would the amount of work change if she used a ramp to help her? 2 m 5 kg

Science STAAR Need to Know Work – the energy needed to move an object over a certain distance Force = mass x acceleration Force = 5 kg x 9.8 m/s 2 (gravity) Force = 49 Newtons Work = force x distance Work = 49 N x 2 m Work = 98 Joules A ramp would reduce the required force, but the distance would increase. The amount of work would not change. 2 m 5 kg

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49Science STAAR Need to Know A lever is a bar that rests on a support called a fulcrum which lifts or moves loads. A lever is a bar that rests on a support called a fulcrum which lifts or moves loads.

50Science STAAR Need to Know Types of levers

51Science STAAR Need to Know A pulley is a simple machine that uses grooved wheels and a rope to raise, lower or move a load. When a rope passes over a wheel, it changes the direction of effort (pull) needed to move the load. This pulley has 1 wheel, so it changes the direction of pull 1 time. The input force is the same as the weight using the pulley.

52Science STAAR Need to Know Wedge A wedge is an object with at least one slanting side ending in a sharp edge, which cuts material apart.

53Science STAAR Need to Know An inclined plane is a ramp used to reduce the effort needed to raise or lower an object over a vertical height. It is easier to climb stairs to get to a second floor than to climb straight up a rope. It is easier to walk up a long, gentle hill than to climb up a short, steep hill. Examples of inclined planes: Loading ramp; Stairs or wheelchair ramp Mountain road; Threaded screw. The ancient Egyptians used inclined planes, or ramps, to move huge blocks of stone to build the pyramids.

54Science STAAR Need to Know A screw is an inclined plane wrapped around a pole

55Science STAAR Need to Know Wheel & axle A wheel with a rod, called an axle, through its center lifts or moves loads.