Unit F: Chapter One

1. Unit F: Chapter One Forces and Motion

2. Science Question of the Day • What causes the noise when you crack your joints? _________________________________ _________________________________ _________________________________

3. Gravity • Gravity is a specific kind of _____________. • A force is simply the ________ or a _________ on an object. • Can you think of some examples of pushes and pulls on objects? ___________________________________ _______________________________________________ • Take my soccer ball for example… • How about my yo-yo…

4. Gravity • Kicking the soccer ball I am applying a force quickly to an object. • Forces can also be added over ________________. • What are some examples of forces applied over time? • Think about my car… • Or an elevator…

5. Gravity • Some forces are ___________________ acting on us. • Gravity is an example of a ____________ that is always acting upon us no matter where we are!

6. Gravity: Take notes about the video here. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________

7. Gravity • Each piece of ____________________ in the universe no matter how large or how small _______________ on one another. • This force is called ___________________. • We see this most on Earth with how objects ________ ___ _______ ________________ like my bouncy ball. • Our gravity keeps everything _____ the earth, even the oceans! • If we didn’t have __________ or we had a weaker __________________ force, our water and some of our atmosphere might ___________ _____ into space!

8. Gravity • Even though gravity is what keeps us ______ the Earth, it is a pretty ___________ force. • My bouncy ball and soccer ball _____________ have gravitational force. • Do you think if I put them on the ground they will roll toward one another? ___________ • Let’s find out…

9. Gravity • What do you know about that? They didn’t roll together! • Why not?______________________________________ ________________________________________________ • It’s not because of their size. ________ has nothing to do with gravitational force. • It depends of the ____________ of the objects and the __________________ between them. • Think about the planets. Jupiter is huge, but it’s gravitational pull is ______ stronger than say Uranus. It’s all about the ________, baby!

10. Mass and Gravity • The more an object ______________ (weight is relative, but we’ll use it here since we are all Earthlings, I think…) the _____________ gravitational pull it has. • Remember, we said that some objects can be very _____________, but ___________ a lot while some objects can be very __________ and weigh a ____________ amount. • Take a marble and a beach ball for example. Which has more mass? ________________________________ ________________________________________________

11. Distance and Gravity • The _________________ you are to something the _________ gravitational pull you will feel. • We notice this when we think about the sun and the Earth. • The sun is about 330,000 times more ___________ than the Earth, but we feel the Earth’s gravitational pull _________because we are ______________ to it than the sun. • Did you know that if you are standing on a mountain top you have ________ gravitational pull from the Earth than you do if you are standing at _____ _________?

12. Can gravity be measured? • Yes! Gravity can be measured in a unit called _______________. • Any ideas as to why it is called a newton? __________ ________________________________________________ • When we step on the scale we are measuring the __________ of ____________ on ourselves. • We can express our weight in _______________ just as we can in ________________ as newtons.

13. Time for a laugh… • When NASA first started sending up astronauts, they quickly discovered that _____________ _______ would not work in zero gravity. To combat the problem, NASA scientists spent a decade and $12 billion to develop a pen that writes in zero gravity, upside down, underwater, on almost any surface including glass and at temperatures ranging from below freezing to 300 C.The Russians used a pencil. • Get it? The Russians… Wow, that was funny!

14. Time for a little practice… • Read “Gravity” and complete questions 1-6 for homework. The teacher asked little Johnny, “What is the definition of infinity?” Little Johnny replied, “Tonight’s homework assignment.”

15. Science Question of the Day • Why does pepper make you sneeze? _____________________________________ _____________________________________ _____________________________________

16. Speed and Velocity • When you apply ____________ to an object, you are putting the object into _________________. • We can observe the motion in many ways: • Did the object move quickly? __________ Slowly? ______ • How far did the object go? __________________________ • Which direction did it move? _______________________ There are many ways in which we can observe motion. Two ways we are going to look at today are ___________ and _______________.

17. Speed • Let’s think about a pitcher and a baseball. • How fast is he or she really pitching and how can we determine this? ________________________________ ________________________________________________ • How far is the pitcher’s mound from home plate? ________________ • How long did it take for the baseball to go from the pitcher’s glove to home plate? ____________________ • The relationship between the ________ and the _______ is the ____________.

18. Speed • To calculate the speed, you must ___________ the ____________ by the ____________. • Let’s try that in the classroom. • How far am I from my volunteer? ________________ • How many seconds did it take for the ball to reach my volunteer? ______________________ • Let’s do some math! ____________________________ ________________________________________________ • We just used a ratio in real life! Ms. White would be so proud! • It is a comparison of the distance ___________ to time that __________________ during the motion.

19. Speed • We could even take this further and figure out how far my ball could travel in an hour. ________________________________________________ • How many feet are in a mile? _____________________ • What equation could we make in order to determine how many miles per hour my ball traveled? ________ ________________________________________________ ________________________________________________

20. Speed • Speed is difficult to calculate at a __________. • For example, the wind could affect how quickly my ball is moving or the track in which it moves. • If I’m driving a car, I may speed up or slow down depending on traffic patterns. • This is why we determine the __________ speed of objects. • Here’s an example: A trip from here to Disney World is 756 miles. This trip can be made in 12 hours and 49 minutes. • What average speed must we go to get there in this amount of time? _____________________________________________ _____________________________________________________

21. Speed:Take notes about the video here. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________

22. Velocity • Another way to observe motion is ____________. • Velocity is the ________ of an object going _____ a particular ______________. • Suppose two cars pass each other in opposite lanes of an east/west highway. Both cars are traveling at 75 mph, so both have the same speed. But the cars are going in different direction, so they have ___________ _______________. • One car has a velocity of 75 mph heading east and the other is 75 mph heading west.

23. Velocity • Velocity is simply _________ with a _______________. • Think about a race car on a circular track. • The speed may stay ____________, but the velocity changes when the car changes ___________________.

24. Momentum • Could you tell the difference between a bowling ball that was painted like a soccer ball and a real soccer ball rolling down a bowling lane? ________________ • When they hit the pins you could! The bowling ball would knock the pins over, but the soccer ball would only move a couple of pins. • This is because the bowling ball is ______________ and would have more ______________________.

25. Momentum • ________________ is the measure of how hard it is to ________ _________ or _________ an object that is in motion. • Think about football players. Is it easier to stop the quarterback or the lineman? ____________________ • Duh, the quarterback because he is smaller and lighter. • You can determine the ________________ of an object by _________________ the _________ ____________ the velocity.

26. Momentum • Let’s figure out the momentum of the bowling ball. • The ball weighs 8 lbs. • It is traveling at 3 mph. • What is it’s momentum? • How about the soccer ball? • It weighs 1 lb. • It is also traveling at 3 mph. • What is it’s momentum? • Obviously, the bowling pin is the linebacker in this example.

27. Conservation of Momentum • When the bowling ball struck the pins it created a collision. • There is a law of science that states that an object’s momentum ______________ a collision stays the _________ as momentum _____________ the collision if no other forces act on the object. • We can see this by the bowling pins absorbing the force of the bowling pin and scattering in the lane. • This is called the ________ of the ________________ of momentum.

28. Time for a little practice… • Read “Speed and Velocity” and answer questions 1-6 for homework tonight.

29. Science Question of the Day • What is static electricity and how does it work?

30. The Laws of Motion • There are several laws that were discovered by scientists thousands of years ago that describe how objects move. • We all know about Newton and gravity, but some you may not have heard of are Galileo, Aristotle, and Ptolemy. • Over the next few days, we will discover Three Laws of Motion.

31. First Law of Motion • An object at _______ tends to ________ at rest, while an object in _____________ tends to stay in _________ in a straight line until an ___________ force acts on it. • What does this mean? • Objects do not change their velocity unless some force _________ on them. • Example: A hockey puck sitting on the ice does not move until something makes it move. • The puck will continue to travel in the same direction across the ice until a stick changes it or friction slows it down.

32. Friction • Friction is a force that ___________ motion whenever _________ surfaces rub against each other. • Friction is only present when other forces such as ____________ or _________ ___________ are present and act to _______ an object against something else. • Friction is what causes objects that are rolling to ________ once the energy that keeps them moving is ________ than the energy that was required to make them move. • Let’s roll this ball and see what happens.

33. Inertia • Objects tend to ____________ a change in motion. • For example, when you are in your car and you go around a curve, your body tends to want to go in the opposite direction. This is because of ______________. • This is the property that makes it hard to __________ a car when it is parked, or _________ to stop it once it is moving. • Sometimes the first law is called the ______ of ________, but inertia is not a law; it is a ______________.

34. Balanced & Unbalanced Forces • Before we can learn about the Second Law of Motion, we must first learn about ____________ and _________________ Forces. • Which one of these pictures if balanced? Unbalanced?

35. Balanced Forces • We have been learning about forces such as gravity, inertia, friction, etc. • Most of the time, object have _________ than one force acting on them at a time. • A ball rolling across the floor is experiencing all three of the above stated forces. • ________________ forces are forces that are acting _______________ on an object, but are acting in ________________ directions.

36. Balanced Forces • When the forces are balanced, either the object does _______ move, or it moves at a constant ___________. This is called the ________ _____________. • Think about a skier. What forces of motion are acting on him? _______________________________________

37. Balanced Forces • The skier continues down the slopes because the forces of gravity, inertia, and friction are all _____________. • Once he reaches the bottom of the slopes, the force of ___________ will overtake the forces of gravity and inertia, and the skier will eventually stop. • This is when ____________________ Forces take over.

38. Unbalanced Forces • Unbalanced forces cause a _________ in velocity making the object speed up, slow down, or change direction. • In a game of tug of war, two teams are ___________ on the rope. If they are both ___________ with equal force, than the forces are _________________ and the net force is ______________; the rope does not move. • However, if a team pull harder, then the rope starts to move in their direction. • This is an unbalanced ___________.

39. Unbalanced Forces • Think about the following scenarios. How are unbalanced forces acting on the objects? • Speeding up a car • Slowing down a car • Changing the direction of a car Here’s a hint: friction!

40. Forces:Take notes about the video here. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________

41. Time for a little practice… • Read “Balanced and Unbalanced Forces” and answer questions 1-5 for homework due tomorrow.

42. Science Question of the Day • How and why do cats purr?

43. Second Law of Motion • This law explains how an _________________ force changes the motion of objects. The __________ of an object is equal to its mass _______ acceleration • When unbalanced forces act on objects it ___________ the ___________ of the object (its speed, direction, or both). • The rate of this change is called ______________________. • This law states: • The ___________ the force, the greater is the _____________, or change in __________________. • The greater the ___________, the __________________ is the acceleration or change in velocity.

44. Second Law of Motion • So basically, the ________________applied, the __________ it will go. The ______________applied, the _________________ it will go. • And, the _____________you have in an object, the _____________________is needed for acceleration, • Take a miniature car for example vs. a real one. • I can push the miniature with one finger with very little effort, and it shoots forward. • If I tried to do that with my car I would probably break my finger.

45. Second Law of Motion • The _________________ in which force is applied is the direction in which the object ________________. • For example, if an object is already moving and we push it from behind it will simply speed up. • Let’s have a little race.

46. Second Law of Motion • If the _________ is applied from the _______________ direction the object is moving, then it will __________ down the object. • For example, if we were to play bumper office chairs (and we won’t for safety sake), and I were to push my chair into someone else’s chair then it would slow down or stop their motion. • We see this in front-end collision crash tests.

47. Third Law of Motion For every __________ force, there is an ________ and __________ reaction force. • This basically means that forces always come in pairs. • For example, as I am pushing down on this floor with my feet, the floor is pushing back. • The forces are always ___________ and ____________. • If the floor did not push back, I would fallright through.

48. The Laws of Motion:Take notes about the video here. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________

49. Time for a little practice… • You and a partner will be rotating through several mini-experiments and recording your results over the next few days. • All the activities are designed to help you understand the different laws of motion. • At the end of each rotation you will fill out your research guide. This is your final product that will be due next week. • Please make sure your put effort into your research guides as they are worth 100 points!