Science/6/Investigation and Experimentation 7.0 Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
a. Develop a hypothesis.
b. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.
c. Construct appropriate graphs from data and develop qualitative statements about the relationships between variables.
d. Communicate the steps and results from an investigation in written reports and oral presentations.
e. Recognize whether evidence is consistent with a proposed explanation.
f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.
g. Interpret events by sequence and time from natural phenomena (e.g., the relative ages of rocks and intrusions).
h. Identify changes in natural phenomena over time without manipulating the phenomena (e.g., a tree limb, a grove of trees, a stream, a hill slope).
Science/8/Focus on Physical Science 1.0 The velocity of an object is the rate of change of its position. As a basis for understanding this concept:
a. Students know position is defined in relation to some choice of a standard reference point and a set of reference directions.
b. Students know that average speed is the total distance traveled divided by the total time elapsed and that the speed of an object along the path traveled can vary.
c. Students know how to solve problems involving distance, time, and average speed.
d. Students know the velocity of an object must be described by specifying both the direction and the speed of the object.
e. Students know changes in velocity may be due to changes in speed, direction, or both.
f. Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction. 2.0 Unbalanced forces cause changes in velocity. As a basis for understanding this concept:
a. Students know a force has both direction and magnitude.
b. Students know when an object is subject to two or more forces at once, the result is the cumulative effect of all the forces.
c. Students know when the forces on an object are balanced, the motion of the object does not change.
d. Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction.
e. Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).
f. Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion.
g. Students know the role of gravity in forming and maintaining the shapes of planets, stars, and the solar system.
Introduces students to the law of inertia through fun demonstrations, activities, and a funny YouTube video. Students analyze the role of inertia and unbalanced forces in various activities, sports, and life.
Students will formalize their understanding of their existing intuition regarding the tendency for an object at rest to remain at rest. Students will learn how to apply Newton’s First Law and explain the role of unbalanced forces and inertia in sports and everyday life.
Students will be able to:
State and explain the first part of Newton's First Law (an object at rest tends to stay at rest unless acted upon by an unbalanced force).
Give real life examples of the first part of Newton’s First Law.
State and explain the second part of Newton's First Law (an object in motion tends to stay in motion in a straight line at a constant speed unless acted upon by an unbalanced force).
Give real life examples of the second part of Newton’s First Law.
List and explain examples where inertia helps an NFL player, and where inertia makes an NFL player’s task more difficult.
See detailed list below for individual activity materials. Materials will depend upon the teachers’ choice of activities.
Anticipatory Set (Lead-in):
Offer a prize to any student that, after the lesson, can give an example or demonstrate an instance where an object starts moving without a force. Explain that although magicians might be able to create illusions where this seems to be the case, physicists are very confident that it does not happen for the objects around us.
Tell them that the laws of physics apply equally in the laboratory, at home, and on a football field. Share that you are going to watch a video on the science of the NFL and that by the end of the lesson, they will not only understand Newton’s First Law of Motion, but they will be able to apply it to many events in their life and in sports.
Part I: Introduction and Term Definitions (15-20 minutes)
After watching the NBC Learn video on Newton’s First Law, lead a more formal discussion on the First Law, and have them record the two parts on the activity worksheet:
“Try to think of an example where an object starts moving without a force.” Ask students to share any ideas and help them to understand the forces involved. For example, they might suggest that blowing on a piece of paper or dropping a rock are examples, but in both cases there are forces. Explain to them that this is the first concept of the law of inertia, “An object at rest will tend to stay at rest unless acted upon by an unbalanced force.”
Have a similar discussion for the second concept in the law of inertia: “Can you think of an example where an object speeds up, slows down, or changes direction without a force?” This tends to be more difficult, as people tend to think it is “natural” for things to slow down (due to frictional forces). Roll a ball or slide an object and discuss the surface and/or air friction involved. If you have a flat surface and a low friction cart, hovercraft, or block of dry ice, you can demonstrate that indeed “objects do tend to travel in straight lines at constant speeds unless acted upon by an unbalanced force.”
Similarly, explain and define the terms “unbalanced force”, “mass”, and “inertia”.
Share with the students that one of the advantages of studying physics is that much of it they already know, at least informally. Tell them that in a few minutes, they will be conducting a series of very fun activities and using the First Law to explain them.
NOTE: This video demonstrates some of the activities students will be performing as well as many other examples of the First Law in action. As an alternative to this video, you can do some of the demonstrations listed below and discuss them briefly. The video is a little fun and goofy and can also be shown at the very end of the lesson to reinforce the main concepts.
Part III: Inertia Activities (30-40 minutes)
Explain to the students that they will be conducting several relatively short activities, and for each one they will be asked to explain the role of inertia and unbalanced forces. Depending upon time, space, equipment, and level of students, choose appropriate activities from the list below (or other activities, as there are many good ones). These activities can either be set up at different stations through which the students will rotate, or you can get multiple sets of equipment.
It is recommended that the students do one activity and then write it up together as a class, for example the “Flick a Note Card” activity. From there, give them time in small groups to work through selected activities and remind them to include the following for each:
Sketch the setup
Briefly explain what happened
Explain the role of inertia
Explain the role of unbalanced forces
NOTE: If possible have them explore at least one activity for each part of the First Law (something tending to stay at rest, and something tending to stay in motion).
List of Potential Activities (most of these are demonstrated in the YouTube video, “Fun with Newton’s First Law”.
Flick a Note Card
Description: A coin sits on a note card that is placed on a cup. The card is flicked horizontally and the coin drops vertically into the cup.
Materials (per group): One cup, one note card, and one coin.
Catch a Coin off Elbow
Description: A small stack of pennies sit on a person’s elbow. The person quickly rotates the elbow down and snatches the coins in their palm.
Materials (per group): 5-15 pennies.
Crochet Hoop (or homemade loop), Pen Cap, and Bottle
Description: A loop sits atop a cup and a pen cap sits atop the loop. The loop is quickly pulled out from under the pen cap which then falls into the cup.
Materials: Loop (you can make one by cutting 1-inch strips of a file folder, double layering them and taping them into a loop as done in the video, or you can us a crochet hoop), pen cap or comparable object, cup, stick or ruler.
Note: The key to this is to make sure the pen cap is directly above the center of the cup. This is a relatively easy activity, and having students build the loop might be worthwhile. Loops can be several inches to a foot in diameter.
Whack a Stack
Description: Uniform wooden blocks are stacked and the bottom block is continually whacked out from underneath the pile.
Materials: 3-6 wooden blocks, 2-foot stick or piece of PVC pipe.
Note: This works slightly better if the wood grains are aligned and blocks are forced to move parallel to the grain.
Description: Students can use a hovercraft to demonstrate the straight line, constant velocity nature of motion in the absence of significant friction.
Materials: Small toy hovercraft.
Note: It is possible to use dry ice to achieve this, but this would probably be better as a class demo.
Carts, Mass Sets, and Ramps
Description: Students roll a cart down a small ramp or angled surface toward a stationary block or a book of appropriate mass. They can observe the different outcomes as they change the mass of the rolling cart and also the mass of the stationary object.
Description: A sheet or tablecloth is quickly jerked out from beneath some dishes or objects.
Materials: A thin smooth cloth without seams on at least one side (you can cut them off), random dishes or objects with smooth bottoms and relatively large mass.
Note: The key to this is a very quick motion. Snap the table cloth away in one quick motion. Make sure that any seams are cut off so that they do not hit the dishes.
Cool Stunt with cup, ball (or egg), toilet paper roll, and pie tin
Description: A pie tin sits on a cup. On the pie tin is a toilet paper roll with an egg atop the roll. The pie tin is smacked by a broom or stick and knocks the toilet paper roll out from beneath the egg. The egg falls into the cup of water.
Materials: Large plastic cup, aluminum pie tin or small cookie sheet with lip, toilet paper roll or comparable substitute (you can make this with paper), small ball or egg that can sit atop the roll, broom or thick stick.
Note: This is one of the more difficult activities and may be best to save for a class demonstration. The key is to make sure that the ball is directly centered above the cup and to make sure that the broom hits horizontally against the table edge and makes contact only with the pie tin and not the cup.
Have each group of students share their notes with the class for one of the activities.
Afterwards, either in class or for homework, have the students answer the questions on the “Post Activity Worksheet: Inertia”:
List ways in which inertia might help an NFL player in the course of a game.
List ways in which inertia might pose a problem to an NFL player in the course of a game.
List instances in your life where inertia has been a problem.
List instances in your life where inertia has helped you accomplish tasks.
Closure (Reflect Anticipatory Set):
If you have not shown the YouTube video, “Fun with Newton’s First Law” you can show and discuss it. Similarly, ask the students to think about and share a new example of the role of inertia in their lives.
Assessments & notes
Plan for Independent Practice:
Post Activity Worksheet: Inertia
Assessment Based on Objectives:
“Post Activity Worksheet: Inertia” can be used as an assessment.
Possible Connections to Other Subjects:
English: Write a creative essay describing how a particular sport would be different if the mass was inversely related to the inertia. In other words, objects or people with more mass have less inertia.
Adaptations & Extensions:
Discuss the role of inertia in auto accidents and the importance of seatbelts.