Newton’s laws can be complex for students to understand, but become easier with a robot to engage in learning. Students use the robots and attachments to conduct experiments and demonstrate understanding of the laws.
Subjects: ELA, Math, Social Studies, Geography
· Group Size: 1 - 4 students per Dash robot
· Time Required: 2+ hours (4 lessons)
· Online Lesson:
Demonstrate understanding of:
· Newton’s First Law of motion
· Newton’s Second Law of 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.
· When objects touch or collide, they push on one another and can change motion.
· Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects.
· Change presentation of concepts and level of expectations for each grade to match the standards.
· Online Resources for teachers: (these may be beyond most elementary student discussions)
· Small filled bags (a small piece of plastic or bag filled with rice or sand or other objects and tied that is about the same size as the balls that come with the launcher). A variety of objects that weigh more – such as fishing sinkers - can be used as fill in the bags.
· Rubber bands
This lesson can be broken into four classes or sessions:
· Class 1: Newton’s First Law (20 to 30 min)
· Class 2: Newton’s Second Law (20 to 30 min)
· Class 3: Newton’s Third Law (20 to 30 min)
· Class 4: Pushes and pulls (20 to 30 min)
· Unbalanced Force
· See handout – Newton Evaluation Rubric
Introduce Isaac Newton with books, science textbook, or video. Explain that one of Isaac Newton's most significant scientific works is his laws of motion. Tell students that these laws explain why things move the way they do.
Newton’s First Law (write on board)
Objects at rest remain at rest, and objects in motion remain in motion in a straight line, unless acted upon by an unbalanced force.
Place one of the balls for Dash’s launcher in a place where it won’t roll on the desk. Ask students what the ball is doing. They will probably say “sitting there or nothing”. Then ask why the ball is not moving. They will probably say because you are not throwing it. Write Newton’s first law on the board and underline “Objects at rest remain at rest”. Tell them this is what Newton meant. The ball will stay at rest or not move until some action is taken upon it. In other words, it is kind of lazy and wants to keep doing what it is already doing.
Now push the ball so it rolls. Ask what the ball is doing now. They will say it is moving. Now underline the part “objects in motion remain in motion”. Explain that Newton saw that once an object starts to move it will continue to move, like this rolling ball.
Next underline “in a straight line,” Ask - This ball will continue rolling in the direction that I push it until what? They will answer – “Until it runs into something that stops it”. That’s correct. It wants to keep doing what it is already doing – that is rolling or moving in the same direction until air or some other object slows it down or makes it stop. That is what Newton called an unbalanced force. Underline “unless acted upon by an unbalanced force.”
So now we understand Newton’s first law. Let’s all read it out loud together. We could rewrite Newton’s first law as “Things want to keep doing what they are doing until something stops them.”
Next explain that students are going to create an experiment or investigation with Dash to demonstrate Newton’s first law, and then write about it.
Hand out the Dash robots, two balls from the launcher accessory, the bulldozer accessories, tablets with the Go App, and masking tape.
Students conduct experiments and then write a paper explaining Newton’s first law and how they demonstrated that it is true. They may have difficulty with the “unbalanced force” tell them this can be their foot or anything else which stops the ball from rolling.
Next we are going to explore Newton’s second law. It is about the mass of an object and the speed or acceleration of it. (Write the second law on the board.)
Newton’s Second Law
Force equals mass times acceleration. f = ma
(Or a force acting on an object causes it to go faster.)
Put the ball on the table. Let’s take a look at our ball again. If I push it a little, or apply a little force, then it rolls slowly. But if I push it harder, or apply more force, then it rolls faster. So that is the Force and acceleration (underline those words).
Acceleration or the speed an object moves depends on the weight or mass of the object and the amount of force applied. If I apply a little force it will go slowly. If I apply a lot of force it will go faster. (once again demonstrate pushing the ball)
What if I have another object that weighs more, for example Dot? What do I have to do to make Dot move? I have to push Dot a lot harder than this light ball to make it move. The weight of an object is similar to its mass. (underline mass). If I push it the same amount as I push the light ball, then Dot moves slowly. So the more it weighs, the more force we have to use to get it to move.
So now you are going to conduct experiments or investigations with Dash which demonstrate Newton’s second law, and then write about it.
Hand out the Dash robots, the launcher accessory, the balls from the launcher accessory, the small filled bags, tablets with the Go App, and masking tape.
We have balls which have different weights which will represent a change in mass. What we want to know is how does this affect the change in acceleration or speed? If Dash exerts the same amount of force with the launcher, which will go further the plastic balls or the filled bags?
Propose your own hypothesis and then set up and conduct the experiment to test it. Then write a report about Newton’s second law and your experiment.
Next we are going to explore Newton’s Third law. (write on board)
Newton’s Third Law
For every action (force) there is an equal and opposite reaction (force).
What happens when I drop this ball? (Drop one of the plastic balls) It bounces. Why is that? The ball has an action which is pushing down on the floor. (underline action) The floor has a reaction which pushes on the ball in the opposite direction. (underline opposite reaction). We call that a bounce. (show in slow motion how the ball goes down, hits desk, and then comes back up).
When you play T-Ball and swing the bat and hit the ball, does it feel different than when you don’t hit the ball or just swing the bat? Why is that? When you swing the bat you are creating an action. And when you hit the ball you are experiencing the opposite reaction.
Now let’s conduct an experiment with Dash to prove Newton’s third law. In this experiment we will use the bulldozer accessory and balls. Groups will work together and have two Dashes push a ball toward each other until the balls collide. What do you think will happen? Propose your own hypothesis and then conduct the experiment to prove it.
Then write a report about Newton’s third law and your experiment.
How does the direction of a push or pull effect the motion of an object?
Let’s conduct an investigation which will compare the effects of different directions of pushes and pulls on the motion of an object. (write on board)
We will use Dash to provide the motion or force, and the balls are the objects. We have the bulldozer to push, and we have rubber bands for pulls. We need to propose a hypothesis and then conduct the experiment. Then we will collect data and prove our hypothesis. Finally we will write a report about the effects of pushes and pulls, and what we discovered in our experiment.
NGSS Elementary School
K-PS2-1. Plan and conduct an investigation to compare the effects of different strengths or different directions of pushes and pulls on the motion of an object.
K-PS2-2. Analyze data to determine if a design solution works as intended to change the speed or direction of an object with a push or a pull.*
PS2.A: Forces and Motion
Pushes and pulls can have different strengths and directions. (KPS2-1),(K-PS2-2)
Pushing or pulling on an object can change the speed or direction of its motion and can start or stop it. (K-PS2-1),(K-PS2-2)
PS2.B: Types of Interactions
When objects touch or collide, they push on one another and can change motion. (K-PS2-1)
PS3.C: Relationship Between Energy and Forces
A bigger push or pull makes things go faster. (secondary to K-PS2-1)
ETS1.A: Defining Engineering Problems
A situation that people want to change or create can be approached as a problem to be solved through engineering. Such problems may have many acceptable solutions. (secondary to KPS2-2)
MS-PS2-1. Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects.*
MS-PS2-2. Plan an investigation to provide evidence that the change in an object’s motion depends on the sum of the forces on the object and the mass of the object.
PS2.A: Forces and Motion (MS-PS2-2)
For any pair of interacting objects, the force exerted by the first object on the second object is equal in strength to the force that the second object exerts on the first, but in the opposite direction (Newton’s third law). (MS-PS2-1)
The motion of an object is determined by the sum of the forces acting on it; if the total force on the object is not zero, its motion will change. The greater the mass of the object, the greater the force needed to achieve the same change in motion. For any given object, a larger force causes a larger change in motion.
All positions of objects and the directions of forces and motions must be described in an arbitrarily chosen reference frame and arbitrarily chosen units of size. In order to share information with other people, these choices must also be shared.