Slide 1 / 106
Slide 2 / 106 3rd Grade Motion and Stability 2015-11-09 www.njctl.org
Slide 3 / 106 Table of Contents Forces and Motion Review Balanced and Unbalanced Forces Motion prediction from patterns Non Contact Forces Click on the topic to go to that section
Slide 4 / 106 Forces and Motion Review Return to Table of Contents
Slide 5 / 106 Review! How far do you have to walk to get to the chalkboard? How far away is your teacher's desk? Teacher How many steps do you have to take to reach the bathroom?
Slide 6 / 106 Review Those questions have one thing in common - what is it? is how we measure how far away an item is. "The chalkboard is 7 steps away." "The desk is 3 steps away." "The bathroom is 29 steps away."
Slide 7 / 106 Distance The farther away something is, the its distance is from you. The closer something is, the its distance is from you. Teacher What's farther from you now, your desk or your home?
Slide 8 / 106 1 Which object is the closest to you (and has the smallest distance from you)? A Your house B The Moon C The Sun
Slide 9 / 106 Review What takes longer to do, watching a TV show or washing your hands after dinner? What do we measure to figure this out?
Slide 10 / 106 Review To figure those answers out we need to measure! is used to show how long it takes to do something.
Slide 11 / 106 Time What are some units we use to measure time? Think about very small measurements and very large measurements! Make a list at your table.
Slide 12 / 106 2 When talking about how far away something is from you, we use the word. A time B distance
Slide 13 / 106 3 If you measured how long your desk is, you would be talking about a. A time B distance
Slide 14 / 106 4 If you measured how long it takes to walk from your house to your friend's house, you would be talking about. A time B distance
Slide 15 / 106 5 If you were timing how long it took to walk a mile, you would probably use as your unit. A seconds B minutes C hours D days
Slide 16 / 106 6 If you were timing how long it took to blink your eyes, you would probably use as your unit. A seconds B minutes C hours D days
Slide 17 / 106 7 If you were timing how long it took to fly from Africa to Spain in a airplane you would probably use as your unit. A seconds B minutes C hours D days
Slide 18 / 106 8 Which of these activities takes the longest to do? A Eating dinner (half an hour) B Brushing your teeth (two minutes) C Watching a movie (hour and a half)
Slide 19 / 106 Discussion Questions Does it take longer to walk or run home? Do people walk or run when they are in a race? Why? When you walk, are you going slow or fast? When you run, are you going slow or fast?
Slide 20 / 106 How fast do you go? The word describes how fast or how slow you go. How do you know whether you are going fast or slow?
Slide 21 / 106 Speed Objects with more speed can move a greater distance in a set amount of time. Teacher This is why the fastest runner reaches the finish line first.
Slide 22 / 106 Speed Objects with less speed move a shorter distance in a set amount of time. This is why it takes you longer to move somewhere if you are walking instead of running.
Slide 23 / 106 Speed Math Speed, mathematically, is distance divided by time. Distance Time = Speed Teacher Moving 10 meters in 5 seconds gives you a speed of (10 meters 5 seconds) meters per second.
Slide 24 / 106 9 A block is pushed 30 meters in 5 second. What is its speed?
Slide 25 / 106 10 A baseball is thrown 26 meters in 2 seconds. What is its speed?
Slide 26 / 106 11 From the last 2 examples, which is faster? A block B baseball
Slide 27 / 106 12 Which of these is the slowest? A A walking man B A running track star C A speeding car
Slide 28 / 106 13 You slide a book, which moves 6 meters in 2 seconds. What is its speed? A 2 m/s B 3 m/s C 4 m/s
Slide 29 / 106 Distance, Time, and Speed The following lab explains what distance, time, and speed are through various activities
Slide 30 / 106 Forces What is this man doing? What is this man doing? Teacher
Slide 31 / 106 Forces There is a name for pushing or pulling something. When you push or pull something, you are using a force! A force is a push or a pull. Similar to how we can measure distance in and time in, we measure force in Newtons (N).
Slide 32 / 106 Forces A force is a push or a pull, and is measured in Newtons (N). By the way, where did the word Newton come from? Teacher
Slide 33 / 106 14 This is an example of a. A push B pull
Slide 34 / 106 15 When you ring a doorbell, you the buzzer. A push B pull
Slide 35 / 106 16 This boy is pushing his wagon. True False
Slide 36 / 106 Motion When you or on something and make it move, you are causing motion! The harder you push or pull on something while it is moving, the more you change its motion. More force leads to more change in speed.
Slide 37 / 106 Motion Using a force on an object changes its motion. Imagine a ball rolling towards you. When it gets to you, you can push the ball away from you and slow it down. If you keep pushing hard enough, you can stop the ball.
Slide 38 / 106 Motion If you kick a soccer ball, it eventually stops. What pushes back on the ball to make it stop?
Slide 39 / 106 Friction The ball stops its motion due to a force called friction. Friction is the force from two surfaces rubbing against each other. Friction is always present when two objects rub against one another. What two objects are rubbing in this example? Motion of the ball Friction
Slide 40 / 106 Friction The friction force always acts against the object's motion. It always tries to slow things down. The grips on these socks provide more friction with the floor than the socks alone. Why is friction important to have with these socks?
Slide 41 / 106 Friction The friction between two objects depends on the surface of each object. What will move farther, a hockey puck pushed across a gym floor, or a puck pushed on ice? Teacher
Slide 42 / 106 Examples of Friction At your table, talk about what you know about these two sports and how friction is involved with them.
Slide 43 / 106 17 Which example has the most friction? A A skater moving on an ice rink B A box pushed on tile that slides far before stopping C A box pushed on gravel that stops moving instantly
Slide 44 / 106 Balanced and Unbalanced Forces Return to Table of Contents
Slide 45 / 106 Balanced and Unbalanced Forces We already know that a force is a push or pull. When you push on a ball, it moves. But, when you push on a wall, it doesn't. Why? When you play tug of war, even though both sides are pulling, the rope only moves in one direction. Why? Teacher
Slide 46 / 106 Balanced and Unbalanced Forces The answer is because of balanced and unbalanced forces! What do you think it means if a force is balanced? What do you think it means if a force is unbalanced? Teacher
Slide 47 / 106 Balanced and Unbalanced Forces Explain what is happening in this picture. Does this show the boys being balanced or unbalanced?
Slide 48 / 106 Balanced and Unbalanced Forces Explain what is happening in this picture. What is different about this teeter totter compared to the last one? How is this one balanced?
Slide 49 / 106 Net Forces In order to understand balanced forces, we should understand what net force is first. Net force is the total force applied to an object. 10 Newtons 5 Newtons Who is going to win this tug of war? How do you know?
Slide 50 / 106 Net Forces If one person pulls with 10 N of force on the left side, and the other person pulls with 5 N of force on the right side of a box, the net force is (10 N - 5 N) = 5 N of force to the left! 10 Newtons 5 Newtons 5 N more force to the left
Slide 51 / 106 Net Force Example Problem If you push with 15 N of force on the left side of a box, and push with 6 N of force on the right side of a box, what will the net force on the box be? 6 N 15 N?
Slide 52 / 106 Net Forces Try this example! force 2 = 5N force 1 = 5N What is the net force on the book?
Slide 53 / 106 18 What is the net force applied to this box? 3 N 8 N Teacher
Slide 54 / 106 19 What direction will the box move? A right B left C it will not move at all 3 N 8 N
Slide 55 / 106 20 What is the net force applied to this box? 2 N 6 N Teacher
Slide 56 / 106 21 What direction will the box move? A right B left C it will not move at all 2 N 6 N
Slide 57 / 106 Balanced Forces Balanced forces are two forces, equal in size, acting in opposing directions on the same object. When the forces on an object are balanced, the object does not move OR stays moving at a constant speed. Each finger is pushing with the same force on the toy car. What is the net force?
Slide 58 / 106 Balanced Forces When a book lies on a table, the forces on it are balanced. Gravity pulls down on it, but the table pushes up on it. table pushes up on the book SCIENCE As a result, the book doesn't move. gravity pulls down on the book
Slide 59 / 106 22 A student applies 5 N of force to the left side of a box. Another student applies 5 N to the right side of the box. What is the net force applied to this box? 5 N 5 N
Slide 60 / 106 23 What direction will the box move? A right B left C it will not move at all 5 N 5 N
Slide 61 / 106 Balanced Forces What are some examples of balanced forces? With a partner, come up with a list of 5 examples. Teacher
Slide 62 / 106 24 Which of these are a balanced force? A Two students push on a car, and it speeds up B A book slides to a stop across a table C Two groups play tug of war, and the rope does not move
Slide 63 / 106 Unbalanced Forces If the opposing forces are not equal, then they are unbalanced. When you throw a bowling ball, you are applying an unbalanced force. Teacher Name 3 other examples.
Slide 64 / 106 25 Which of these represents an unbalanced force? A Two forces push a box, resulting in a net force of 0 Newtons B A student pushes on a wall and does not move C You kick a soccer ball into a goal
Slide 65 / 106
Slide 66 / 106 Conclusion Questions For any object to stay completely still it must overcome what force that always pulls down? In all of the activities you did what did you notice was the difference between unbalanced and balanced? Explain in terms of force. In which direction did all the forces that went against gravity go? Were they always enough to stop the object from falling? Can you think of some other activities in your life that show balanced or unbalanced forces? Do you think you can try it in class ask your teacher.
Slide 67 / 106 Motion Prediction From Patterns Return to Table of Contents
Slide 68 / 106 Predicting Motion Lab Predict the motion when a... Ball collides with a wall? Ball is thrown straight up? Magnet and is near paper clips?
Slide 69 / 106 Predicting Motion Lab What forces are present? Gravitational force Collision force Magnetic force
Slide 70 / 106 Motion Prediction From Patterns How does the swing move? Where will the swing be next? Draw it on the picture.
Slide 71 / 106 Motion Prediction From Patterns This question is all about motion prediction. Some objects always follow a pattern of motion. A ball thrown straight up will come straight down, and a swing keeps moving left and right.
Slide 72 / 106 Motion Prediction From Patterns As a result, we can predict some objects' motion. Science does not just explain things. Instead, it allows us to make really good predictions of new things that will happen! We do this by observing something, and predicting what will happen in the future to it. We then do an experiment, measure and record data, then see if the prediction came true.
Slide 73 / 106 Motion Prediction From Patterns If our prediction came true, and it happens many, many times, we can create a theory (an explanation for what is happening). What if the prediction didn't come true? What do we do then?
Slide 74 / 106 Motion Prediction From Patterns A pendulum is a ball attached to a string, which is taped to some point. The ball attached to the string is allowed to move freely. It looks just like a swing!
Slide 75 / 106 Motion Prediction From Patterns Predict the path of motion for this pendulum. What is the reasoning behind your prediction? move the block for the answer
Slide 76 / 106 Motion Prediction From Patterns Draw the path of this ball if it is thrown in the direction of the arrow Teacher Draw the path that the kids will follow on the seesaw.
Slide 77 / 106 26 A ball is thrown off a building. Which diagram best predicts its path? A B C
Slide 78 / 106 Non-Contact Forces Return to Table of Contents
Slide 79 / 106 Non-Contact Forces Have you ever seen paper clips move towards a magnet without touching it? Why does an apple fall to the ground when you let go of it, even though nothing is touching it?
Slide 80 / 106 Non-Contact Forces As it turns out, forces are actually not as simple as just a push or a pull. Objects can apply a force to one another without actually touching. Things do not have to touch to cause a change in motion. These are known as non-contact forces. Do you know the names of either of the non-contact forces from the last slide?
Slide 81 / 106 Non-Contact Forces Gravitational, electrical, and magnetic forces are all examples of non-contact forces.
Slide 82 / 106 Gravitational Force Gravitational force occurs when two bodies physically attract one Earth, due to its extremely large mass, pulls objects (like cows on diving boards) towards it, even though no contact is being made.
Slide 83 / 106 Gravitational Force This is why a book speeds towards the ground when it is dropped. This is also why the moon does not move away from Earth.
Slide 84 / 106 27 Gravity acts as a non-contact force, pulling down on objects towards Earth. True False
Slide 85 / 106 Magnetic Interactions Lab Experiment 1: Bring the ends of two bar magnets near each other. Experiment 2: Using ring magnets and the stand, try to stack the magnets on the rod so that none of them touch (observe 2 rings first, then add the rest).
Slide 86 / 106 Magnetic Interactions Lab Experiment 3 Place a compass flat on your hand or table. Without being near a magnet, can you change the direction that the compass needle points? Experiment 4 Put the magnet near each of the objects you were given and write if they attract or not
Slide 87 / 106 Magnetic Interactions Lab Experiment 5 Using a stock or pencil, string, and a ring magnet, make a fishing pole. Use this to pick up a paperclip, then try to make a paperclip chain by touching one paperclip to the next.
Slide 88 / 106 Magnetic Force Notice that magnets tend to push or pull on one another and other objects. Magnets can apply a force to something without touching it due to a magnetic field.
Slide 89 / 106 Magnetic Force A magnetic field is the area in which a magnet can apply a push or pull force without touching the object. Objects in a magnetic field can be attracted or repelled by the magnet. These nails are in the magnetic field, so they move towards the magnet.
Slide 90 / 106 Magnetic Force You might notice sometimes magnets don't work if they are far from another object. The farther an object is from the center of a magnetic field, the weaker the force applied to it. The nails at the top are outside the magnetic field and are not affected by the magnet.
Slide 91 / 106 Magnetic Force Magnets have a North and South pole (just like Earth). The magnetic field goes from the North pole to the South pole. This is why like poles repel each other, and opposite poles attract each other!
Slide 92 / 106 Magnetic Force Earth itself is actually one giant magnet! It has its own magnetic field. That's how compasses work! The metal arrow lines up with the magnetic field of Earth. Teacher
Slide 93 / 106 28 A magnetic field goes from the North pole to the South pole of a magnet. True False
Slide 94 / 106 29 You have a magnet that has the North and South pole marked. How can you use this magnet to determine the North and South pole of other magnets? Students type their answers here Discuss this at your table. Click A on your responder when you are ready to share your ideas.
Slide 95 / 106 Magnetic Racing This lab explains and demonstrates magnetic forces by racing two magnets.
Slide 96 / 106 Electric Force Have you ever rubbed a balloon on your head and stuck it to a wall? Why does that happen? Have you ever gotten to school and then see you have pet hair stuck to your clothing? Why does that happen?
Slide 97 / 106 Electric Force This occurs because of electric forces. All objects have charge, which is just a group of positives and negatives. Just like how magnets two poles, (North pole and South pole), the two kinds of charges are called positive (+) and negative (-). Electric force is how these charges interact with one another.
Slide 98 / 106 Electric Force When the same magnetic poles come near each other, what did we say happens? What do you think happens when two positive charges come near each other? Teacher Opposite charges attract each other and identical charges repel each other.
Slide 99 / 106 Electric Force As you rub a balloon on your head, you are charging it by giving it negative charge. This turns the balloon into one huge negative charge. opposite charges attract This causes the positive charges in the wall to pull on the negative balloon and attract it to the wall! - + + like charges repel - - +
Slide 100 / 106 Electric Force Electric force is not just limited to balloons and hair. If you rub a glass rod with a silk cloth, it can attract small pieces of paper. This also applies to many other objects! Can you think of any other examples?
Slide 101 / 106 Electric Force Demonstration Click on the image to access a PHeT demonstration which shows how rubbing a balloon on a sweater can cause it to become attracted to a wall.
Slide 102 / 106 30 If you put a balloon with negative charges next to a sweater with positive charges, the balloon will move towards the sweater. True False
Slide 103 / 106 31 If you put a comb with positive charges next to another comb with positive charges, they will move towards each other (attract). True False
Slide 104 / 106 Electricity Lab What are electrostatic forces? Electrostatic Forces-forces of attraction and repulsion through charged materials
Slide 105 / 106 Electricity Lab Balloon and cloths Comb, fur, and water Comb, fur, and paper Comb, fur, and coil Socks, Carpet, and teacher Balloon and balloon
Slide 106 / 106 Building With Magnets The following lab is an overall project, giving a full demonstration on magnetism.