Motion & force

Inclinded plane, ball runs, s & Newton

Questioning is the foundation of all learning.
The first step in rejecting not knowing is to ask, why?
Sweetland

Introduction

Contents Overview

Activities
Expansion activities
- Ball runs & coasters
- Structures and bridges
K'Nex® vehicle album
Football Helmet timeline
Newton's Cradle with bowling balls

This page includes activities related to force, mass, and movement. With subtopics that include: energy, conservation of energy, potential energy, kinetic energy motion, speed, slope, mass, height, gravity, friction, and Newton's Laws.

I did the activities originally with K'Nex systems. Years later, with the kits out of production, I thought the activities could be modified using different systems or using posterboard or cardboard.

While the activities can be done with different setups here is some information to decide what materials might be best for you.

Vehicle - Cars or marbles or ...

First, decide if you want to use cars or marbles. If cars, what kind of cars. I used cars, because I wanted to adjust the cars weight in later exploration. If you don't desire this, you may mant to use marbles.

K'Nex® vehicle album
Hot wheels

If marbles (spheres), decide what kinds

Tracks

Then decide car tracks or marble run and how to make them.

Originally I used.

K'Nex downhill run - In the beginning I connected two sets of K'Nex x-treme Downhill Thrill Play Set #12026. The set is no longer available new, however, most of the parts are available from other sets, except the red ramps. K'Nex for instruction sets for parts or substitutes.

You could use K'Nexs for a frame and replacement tracks. There are different brands of racetrack tracks available some with two parallel tracks, and a variety of hotwheel tracks, or could use posterboard. However, it may take a bit of creativity to figure how to keep the car on a poster board track if you use K'Nexs for the framework. Maybe fold the edges or glue narrow side strips on the sides.

If use marbles, you could use a wider incline plane and marble runs. They can be made easily by rolling paper or folding craftpaper.
If you are interested - explore tracks made with Rolling Spheres - Tracks & energy

Related Units

Motion - Motion unit: Spinners: tops, zoomers, twirlers, rollers: wheels, wheels & axles, cups, & spheres unit with plans & activities
Gravity friction & motion - Motion: force, gravity, acceleration, inertia, friction, & energy unit plans & activities
Relative position & motion - unit plans & activities
Investigation directory
Helmet safety and testing - Science article mostly related to football - Use to create challenges to test different kinds of containers (helmets) for eggs in an egg crash or drop. Include timeline of football helmet development.

Activities in this page

While these activities can be done with different kinds of tracks, cars, or marbles and spheres. I will stick to one combination for each activity. Adjust according to your needs.

Exploration of force - hand clap.
Will it get up the hill? - release from top of hill to see if it will go all the way up the other side.
How far will it roll or travel? - roll objects down an inclined and see how far they travel.
Down Hill Crash and Slide -
Down Hill Long Track
Down Hill Runs from Different Heights
Double Down Hill Vibrations

Exploration of force - hand clap

Start with the hand clap challenge and move to the will it get up the hill activity when you believe it might be necessary to keep the learner's attention. You can always return to Newton, magnets, and more as you deem appropriate.

Challenge

Move your hands toward each other so one hand feels a small push and the other a strong push?

What happens when you do? They move.
What is the force on each hand? One is more than the other.
Which is more? The one moving forward
Which is less? The one moving backward.

What if they are brought together fast? There is a clap.

What direction is each hand pushing, when they clap? left right & right left. Each in the direction of their motion.
Which happens first? neither. They happen at the same time. One does not cause the other.
How do the forces compare? When you clap, each hand feels the same force.
Which force is strongest? They are the same. Equal strength in the opposite direction.
Even if you hold one hand perfectly still and strike it with the other, both hands still experience the exact same force.

If we summarize what happens we can use Newtons' three laws of motion.

Newton's laws of motion

1. Newton's First Law (Law of Inertia) - An object at rest stays at rest, and an object in motion stays in motion, unless acted upon by an external force.

Before the clap: Your hands sit perfectly still. They will not move on their own because their inertia keeps them at rest. If there is an external force. The contraction of your chest and arm muscles - acts upon them. And they swing. After your muscles push your hands into motion, your hands want to keep moving forward. They would continue right past each other if they did not crash into one another, which makes them stop.

2. Newton's Second Law (Law of Acceleration) Force equals mass times acceleration. F = m*a. The harder and faster your muscles contract (acceleration), the more force your hands generate. The mass of your hands is the same (constant), therefore, how fast you swing your arms directly relates to the impact force. The clap: This second law also dictates how the hands stop. When your palms collide, their speed drops to zero almost instantly. Because the stopping time is short, the deceleration is large. This large deceleration creates a huge spike in force, which causes the stinging sensation in your palms and forces the surrounding air outward to create the clapping sound.

3. Newton's Third Law (Action & Reaction) For every action, there is an equal and opposite reaction.The Collision: When your right hand hits your left hand, your right hand exerts a forward force on the left one (the Action). Simultaneously, your left hand exerts an equal and opposite backward force on your right hand (the Reaction).The Result: Even if you hold your left hand completely still and strike it with your right hand, both hands feel the exact same amount of sting. Your stationary left hand pushes back on your moving right hand with the exact same amount of force that it receives.

Further consideration

Consider two magnets. They can attract or repel. They happen together at the same time. One is not causing the other. Their interaction causes the force and if strong enough, motion.

When two forces interact one is not causing the other. Both forces are the same cause: their interaction.
Consider how gravity pulls objects. Each object pulls on the other. Neither one pulls on the other. They pull on each other. A basketball falling to the ground results in gravity pulling on the ball and gravity pulling on the Earth with the same force.

Whenever one object exerts a force on another object, the second object exerts an oppositely directed force of equal magnitude on the first object.

It helps to remember that because these action/reaction forces act on different objects (one on object A, and the other on object B), they do not cancel each other out. For example, if you push a heavy wall, the wall pushes back on your hands with the exact same force, which is why you feel it!

Action-reaction pairs never cancel out, but different forces acting on the exact same object can cancel out.

It depends on how many objects you are considering.

Examples:

1. Forces that NEVER cancel out (Newton's Third Law).

These forces always act on two different objects. You cannot add them together because they are happening to different things.

The Rule: Object A pushes Object B, and Object B pushes Object A.

Example: You jump off a small boat. You push the boat backward, and the boat pushes you forward. Why they don't cancel: One force is acting on the boat, and the other force is acting on you. Because they act on separate objects, they cannot cancel each other out. Both you and the boat will move.

2. Forces that CAN cancel out (Balanced Forces)

These forces all act on the exact same object. You can add them together to find the net force.

The Rule: Multiple external forces push or pull on Object A at the same time.

Example: You and a friend push on opposite sides of a heavy box. You push right with 50 Newtons, and your friend pushes left with 50 Newtons.Why they cancel: Both forces are acting on the same box. Because they are equal in size but opposite in direction, on that single object, they balance out to zero. The box stays perfectly still.

Summary

Action-Reaction Pairs: Two forces + Two different objects = Never cancel.
Balanced Forces: Two forces + One single object = Can cancel
Forces always come in pairs. - You can never have a single, isolated force in the universe
They always act in opposite directions. - If Magnet A pulls Magnet B to the left, Magnet B pulls Magnet A to the right. And they happen at the same time.
They happen at the same time. - The action doesn't cause the reaction a split second later; they exist together as one single interaction
They act with equal magnitude on each object in the interaction. - Even if a massive truck crashes into a tiny bug, the bug exerts the exact same amount of force on the truck as the truck exerts on the bug.
Forces in these paired interactions are always the same types of forces. - If the action force is a gravitational pull, the reaction force must be a gravitational pull. If the action is frictional drag, the reaction is a frictional drag. You will never have a magnetic action cause a gravitational reaction.

Assess by asking to explain the forces.

Between two hands pulling on a rubber band. Rubber band pulls equally on both hands in the opposite direction it is being stretched.
Forces on a blown up balloon. Balanced air pressure inside pushing out and outside pressure pushing in.
Forces on a filled balloon with the air escaping. On a filled balloon the air pressure inside pushes outward in all directions. When released the unbalanced forces push the balloon around the room. They are unbalanced, because the force, where there is now a hole, has no outside pressure to hold it in so the air just leaves. Therefore, there is a force pushing up on the balloon but none pushing down, because there is a a hole there. The result is more air pressure pushing up on the balloon than air pressure pushes down with the resulting motion up.

What other situations that involve forces are the same as these hand clapping examples? When any two objects collide.

With a background on forces, your're ready to explore!

Will it get up the hill?

Challenge

If a car is released at the top of one side will it travel up the other side?

Materials

K'Nex downhill run - I connected two sets of K'Nex x-treme Downhill Thrill Play Set #12026.
Vehicle used is pictured to the right and it is modified in later explorations as seen in the K'Nex® vehicle album. Cars were adjusted to add washers, as weights or mass to explore how that effects the different runs.

U shaped track set up — Double downhill set connected

Procedure

Set up the track and have a pair of learners release and return a car a couple of times.
After a few trials and everyone is satisfied a car will not make it up the other side suggest they could explore some more to what relationships they can discover.

Follow up explorations

The learners were next challenged to collect data to show a relationship between the release height of a vehicle and the height to which the vehicle will climb up the other side of the valley or U shaped run.

Suggestions:

Consider only vertical distance when making the measurements.
Measure to the nearest centimeter.
Decide on test run heights: select three - 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm
Record: release height
Record: climb height
Review the data.
Graph the data.
Make a rule for how high a ball needs to be released to make it over a hill that is a certain height.
Explain why or how your rule works.

Lab worksheet

Decided on procedure:

Car will be released from the top of the hill and we will measure how high, off the floor the car travels. Then repeat from 10 cm from the top, 20 cm from the top and 30cm.
The height will be measured from the floor vertically to the high point on the ramp that the car reaches. Threee trials will be run for each.

Trials	Top of hill	10 centimeters	20 centimeters	30 centimeters
Distance rolled trial 1
Distance rolled trial 2
Distance rolled trial 3
Total
Average

Graph (Graphing notes)

Graph paper

Discovery and relationship

How Far will it roll

Challenge

How far will cars (or spheres marbles) roll or travel from the bottom of an inclined plane when they start from different distances up the inclined plane?

Suggestions

Decide how to measure the starting point. Measuring directly up the included plane is the easiest and can be marked on cardboard if you use a carboard inclined plane. Like in the photo.
The other option is to measure the verticle height of the starting point. Which is probably better if you are going to change the height of the inclined plane during the exploration rather than the starting point.

Possible procedure

Set up the inclined plane and decide how to measure and record a starting point, how many starting points to explore, and how many trials for each starting point.

Then decide how to record data and plot in a graph.

Notes:

Lab worksheet

Trials	10 centimeters	20 centimeters	30 centimeters	40 centimeters
Distance rolled trial 1
Distance rolled trial 2
Distance rolled trial 3
Total
Average

Graph (Graphing notes)

Graph paper

Down Hill Crash and slide investigations

Focus questions
Procedure
Photo album
Sets of data and graphs

Focus Questions

How far can the car push a bale of different weights?
Can the car crash into a bale and not move the bale?
What is the least amount that the bale will move?
How does adding weight (washers) to the bale change the distance it will slide when it is hit by the car?
How does changing the angle change how far it will slide?
How does adding weight to the car change the distance the bale will slide?

Note:

I starteed with a U shaped track to focus on the idea that the cars lost energy when the car wouldn't go all the way up the other side. This led to a conversation about conservation of enery and what happens to the motion energy if it is conserved.

When learners explored having the car go down the track and collide, they wanted to take the U track apart to let the crash happen on the flat tile floor. When they did, the vehicle or ball would run off the end of the track, onto the floor, crash, push the slider across the floor and crash into the wall. When light weights were added, they too would slide across the floor and hit the wall.

Therefore, we decided to reassemble the u shaped track and let the slider slide up the hill.

Set up a U shaped track.

Procedure

The K'Nex® DownHill Thrill layout was used (pictures in album below) and K'Nex® vehicle album. The end of one of the plastic bales was cut off so that washers could be put inside. The bale was placed at the of the first dip. The first runs pushed the bale up the jump and across the tile floor. Later runs didn't.

Modified the plastic hay bale (cut the topoff so we could insert washers) and placed it at the bottom of the hill at the point where two tracks met.
Placed a ruler beside the track to measure the distance the bale slide.
Longer slides slid up the hill and across the floor until the bale came to a rest.
Longer slides were easier to measure.
As more washers were added the bale would slide up the hill stop and slide back down.
An observer positioned at the bottom of the track watched carefully to see how far the bale slide before it rolled back.
Three trials were made and recorded in a spreadsheet and graphed with the software.

Learners who participated were a mixed age group from 10-12 years old.

Sample graph & data

Graph of crash and up hill slide

See additional data and graphs

Photo album - Down hill system

Set up of down hill system

Underside and side view of down hill system

Set up with bale at bottom where tracks meet

Bottom of ramp with bale and car

Action!

Three sets of data and graphs

Set 1 Chart and Graph of Down Hill Crash

Car rolls down ramp and crashes into the bale with different mass (number of washers).

Bale slides on ceramic tile.

Number of washers in bale Distance bale slid on tile	0	1	2	3	4	5	6	7	8	9	10	11	12	13
Trial 1	66	41	32	25	28	24	31	20	14	15	13
Trial 2	72	79	56	45	30	35	30	78	21	15	13	65	7	17
Trial 3	100	80	74	33	42	44	41	25	17	15	19	9	9	8
Mean	79	67	54	34	33	34	34	41	17	15	15	37	8	13

Set 2 Chart and Graph of Down Hill Crash

Car rolls down ramp and crashes into the bale with different mass (number of washers).

Bale slides up jump ramp - Layne

Number of washers	0	1	2	3	4	5	6	7	8	9	10	11	12
Trial 1	51	36	10	7	6	4	1	3	2	1	2	1	1
Trial 2	65	41	8	7	5	5	2	3	2	2	3	2	2
Trial 3	56	42	9	6	6	5	3	3	2	2	4	3	3
Mean	57	40	9	6.7	5.7	4.7	2	3	2	1.7	3	2	2

Graph of Down hill crash and up hill slide

Set 3 Chart and Graph of Down Hill Crash

Car rolls down ramp and crashes into the bale with different mass (number of washers).

Bale slides on carpet.

Number of washers in bale Distance Bale Slid in inches	0	1	2	3	4	5	6	7	8	9	10	11
Trial 1	49	23	11	8	7	5	4.5	4.3	4.5	4	3.5	4.5

Graph of down hill crash and slide on Carpet - Alexa and Kalie

Expansion activities

Will it make the turn?

Challenge learners to collect data to show the relationship between turns and the speed of the ball or car.

Create different kinds of turns with a track or ball run.

Different diameters: 10 cm, 20 cm 30 cm
Different angles of the turn 30 degrees, 45, degrees, 90 degrees, 180 degrees ...
Insert each turn in the track or ball run and release the ball from three heights: 10 cm, 30 cm, 50 cm
Repeat with each of the other turns.
Record the data: type of turn, height, results
Review the data
Graph the data
What is the difference in the turns A, B, and C?
Make a rule for safe turns on coasters or ball runs.

Lab worksheet

Procedure

	Turn -	Turn -	Turn -
Start distance -	Trials	Trials	Trials
Start distance -	Trials	Trials	Trials
Start distance -	Trials	Trials	Trials
Summary

Graph (Graphing notes)

Graph paper

How fast is fast?

Challenge learners to collect data to determine the speed of a ball or vehicle as it moves across a smooth surface or track.

Practice how to releases it so it rolls approximately the same speed each time.
Release a vehicle or ball from a point marked on a ramp.
Determine three distances from the bottom of the inclined plane or ramp and place markers: like 100 cm 200 cm 300 cm
Find the time it takes the vehicle or ball to reach each of the distance markers.
Do two or three time measurements for each distance.
Record the data: time to reach each distance marker.
Average the times and calculate the average speed in cm/s
Was the ball’s or vehicle's speed constant? Explain.
Use your data to determine a pattern to predict the speed of the ball or vehicle at different distances or if the car started higher or lower on the ramp. (Extrapolate & interpolate)
Justify your answers.