Addresses NGSS Level of Difficulty: 1 Grade Range: K-2 OVERVIEW In this activity, students will compare two forces of energy on the motion, velocity, and direction of an object. Students will examine how the collision of a moving object with another object causes the object to change direction. Topic: Push, Pull, Speed, Direction Real-World Science Topics An evaluation of the force created when kicking as compared with pushing the object An examination of the ability to control direction of a moving object using different parts of the body (hands as compared with feet) A evaluation of the ability to change the direction of a moving object by colliding it with another object (stationary and moving) Objective After completing this activity, students should be able to explain the strengths of forces created when pushing an object using two different methods. They will be able to share strategies on controlling the direction of a moving object and the ability to strike a target. They will describe how an object changes direction when colliding with another object. NGSS Three-Dimensions Science and Engineering Practices Planning and Carrying Out Investigations With guidance, plan and conduct an investigation in collaboration with peers. Scientific Investigations Use a variety of Methods Scientist use different ways to study the world. Disciplinary Core Ideas PS2.A: Forces and Motion Pushes and pulls can have different strengths and directions. Pushing or pulling on an object can change the speed or direction of its motion and can start or stop it. PS2:B Types of Interactions When objects touch or collide, they push on one another and can change motion. PS3.C: Relationship between Entergy and Forces A bigger push or pull makes things speed up or slow down more quickly. Crosscutting Concepts Cause and Effect Simple tests can be designed to gather evidence to support or refute student ideas about causes. 1
Background Information How does an object move? What are the causes of motion? An object moves when a force is placed against that object. Motion can be caused by either a push against the object or a pull on the object. How does force and pressure change the speed of an object? The Laws of Motion were theorized during the 1600s, by a scientist named Sir Issac Newton. The first law suggests that an object not subjected to any force will either remain still or remain moving at the same speed. A change in the amount of force placed upon an object will increase the speed or velocity of the object. How does causing a moving object to collide with another object change its speed and direction? An object not interrupted (by pushing or pulling) by another object or force will remain moving in the same direction in the same path and at the same speed. However, if the object collides with another object, that object will change directions according to the location of the impact on the object and the force from the object. Key Vocabulary Force a push or a pull on an object that causes a certain amount/power (magnitude) and direction Velocity the measure of how much the motion of an object has change Collide to meet or connect by touching Newton s First Law of Motion an object at rest stays at rest and an object at motion stays at motion unless acted upon by another object Direction the route or point towards which an object goes Materials Needed for Activity Materials Needed for Activity Kick balls or Rubber balls for each two pairs of children Small ball such as a tennis ball Poster board Markers Tape Chart paper Small orange construction cones (usually found with the physical education supplies) (If you don t have access to the cones, use the gym walls as your target background.) Handout on Force and Motion Teacher Preparation Ideally, this lesson will take place in the gym or in an outdoor location with a flat surface area where balls can roll. Areas such as black asphalt area where children play basketball or sports games are ideal for this activity. Draw a small target on poster board large enough for all students to see, but appropriate to be used as the target for the tennis ball. 2
STEPS FOR JUST FOR KICKS 1. Warm-up Activity: Hang the target up on the board while the students are watching. Ask the students what they know about the image on the poster board. Take two or three responses. Show the students the tennis ball. Tell them you are going to attempt to hit the target with the tennis ball. Ask the students to vote whether or not they believe you can hit the target with the ball. After counting their votes, ask them what is needed to hit the target. Ask them if the ball could hit the target if you stood there and held it in your hand. Now, toss the ball at the target using a light amount of force so that you miss the target. Ask the students to describe what happened. Ask them to tell you what to do in order to be more successful in hitting the target. 2. Tell the students that they are going to learn about motion and force. They are going to make targets and investigate how force impacts speed and direction of an object. Ask them if they know what is meant by force. Allow students to share ideas. Explain to them that the tennis ball did not hit the target because of the amount of force applied. Ask them if they think the ball needed more or less force. Discuss their ideas. 3. Next, demonstrate to the students how to create a target. Create a target by drawing three circles inside one another on the poster board or construction paper. Put the students in groups of three to make their targets. Remind the students that you would like them to work carefully and quickly. Allow no more than 5 minutes to draw their targets. 4. Escort the students to the gym or outdoor area for the next portion of the lesson. Once at the gym, tell the students they are going to compare the motion of the ball using two different movements. First, they are to sit on the floor with their legs crossed and attempt to roll the ball at the target. Next, they are going to stand up and kick the ball at their target. Each person in the group will do each motion. Finally, they can attempt to throw the ball at the target. Have the students divide up so that each group has enough space. Pass out the tape and have them place their target signs on the wall (or the cones). 5. While the students are working in groups and comparing the three types of force, walk around the gym, and encourage them to work cooperatively. Check that all students are taking turns and that they are following directions. 6. Bring students together to review what has occurred in the first part of this activity. Ask which of the three methods caused the force that hit the target. Ask them to explain why/how kicking versus pushing versus throwing the ball was better. Discuss how each caused a different speed. Ask which method they thought was easiest for maintaining control over the direction of the ball. 7. Now, tell the students that they will learn something else about motion and force. Demonstrate to the students by selecting a student to roll a ball across the floor. As the ball rolls across the floor, roll another ball towards it so the two balls collide. Ask the students what occurred. Second Grade: Describe the first law of motion to the students. Tell them that it states that all moving objects will keep their same motion unless interrupted by the collision of another object. Ask them if they can think of other examples of the law of motion taking effect. Some examples are found in sports like soccer, football, and basketball or in play such as crashing a bike or skateboard. 8. Allow students to perform the same behavior. One student can roll the ball across the floor. The other can roll a ball in the pathway of the first ball. The students should record what happens to the ball as it collides. Did the ball stop, continue moving, or change directions? 3
STEPS FOR JUST FOR KICKS 9. Bring the student together and discuss what they learned about motion and force. Ask them how does force affect the way a ball moves. Ask them to name some other ways they can use their body to cause force on a ball. Do they think their suggestions will cause more force or less? Would that be a good way to hit a target? 10. First and Second Grade Complete the handouts on Force and Motion Extension Activity Students will now conduct an experiment examining the speed and energy created from pushing a suspended ball as compared with pulling one. They will compare quantitative data (number of swings) and qualitative data (speed) of a suspended ball. The teacher will affix a rope of at least eight feet in length to tennis balls by tying the rope around the ball and putting a knot in the rope. Tie the rope securely so the rope will remain on the ball for this activity. There should be enough rope remaining to tie the tennis ball to a horizontal bar such as a broom or bar from playground equipment. Tell the students they are going to learn about the speed and energy created when pulling an object as compared with pulling it. Take the students to the playground area. Pose questions about pulling and pushing the tennis balls from the bars on the equipment. Make predictions about (1) which will have faster speed and (2) which will swing the most times (back and forth) on the bar. Conduct the experiment. Divide the students into groups of four. Have them pull the balls and release them. They will count number of swings per 5 seconds and count the number of swings until the ball comes to a complete stop. They will do this for pulls. Then, they will push the balls and document the same information (number of swings per 5 seconds, etc.) The students will discuss their findings. Sources http://www.physics4kids.com/files/motion_intro.html http://facstaff.gpc.edu/~pgore/physicalscience/forces-motion.html http://www.physicsclassroom.com/class/newtlaws/u2l1c.cfm http://ag.arizona.edu/pubs/garden/mg/botany/plantparts.html 4
STUDENT HANDOUT Name: Date: Force and Motion You examined three ways to make a ball hit a moving target. Think about the three methods. In the box below, draw the one which one worked the best. 5
STUDENT HANDOUT Why do you think this was the best strategy for causing the ball to hit the target? Use what you have learned about motion, force, and direction. A student from another class wants to know what you found out today about a moving object colliding with another object. Explain what you did today and what you learned. 6