phenomena. Much of the science behind forces and motion can be investigated by first understanding
the three basic laws of motion, as stated by Sir Isaac Newton in 1666.
1 An object at rest tends to stay at rest, and
an object in motion tends to stay in motion
at a constant speed and in a straight line,
until an outside force affects it. This is the
definition of inertia.
2 The more force put on an object, the more
it accelerates. The more mass an object
has, the more it resists acceleration.
Force equals mass times acceleration.
3 For every force, there is an equal but
opposing force. For every action, there
is an equal and opposite reaction.
See if you can find applications of these three laws of motion in your daily experiences.
They govern just about everything that moves, pushes, pulls, launches, flies, zooms, or just stays still.
FOUCAULT PENDULUM
BALL FOUNTAINS
Inquiry Starters: How does the pendulum bob knock down all the balls in
a circle, when it looks like it swings along a straight line? Is the pendulum
really a perpetual motion machine? What makes the pendulum at COSI
keep moving?
Inquiry Starters: What makes the balls stay up in the stream? What prevents
the balls from shooting straight up and out of the stream? Is there anything
special about the stream of water that keeps the balls moving?
What’s Going On? According to Newton’s first law of motion, an object
that is free from all outside forces travels at a constant velocity along a
straight-line path. The only way for the pendulum to trace out the path
along the circle is for the Earth to rotate under the pendulum. The force of
friction, molecules rubbing together due to interaction between the air and
the cable, would eventually slow the pendulum to a stop. (An electromagnet
was installed in the pendulum at COSI to keep it moving.) The balls around
the base of the pendulum are set so two will be struck about every fifteen
minutes and land in the center of the base.
Try This: Go to Adventure and check out the Sand Pendulum, a compound
pendulum, in the Temple of Inspiration. Compare and contrast how both
exhibits work.
➜ OCEAN
What’s Going On? Newton’s Laws of Motion on equal and opposite
reaction work to hold the ball in place within the stream. Because the ball
is off-center in the stream, it will spin. If the ball begins to leave the stream,
the reaction force, caused by the spray of water, is usually strong enough
to pull it back in. Because the ball reacts to small movements by returning
to the stream, the ball is in what we call “stable equilibrium.”
Try This: Go to Gadgets and check out Newton’s Nozzles. Compare and
contrast how the balls stay afloat.
EROSION TABLE
➜ OCEAN
Inquiry Starters: What is the relationship between the speed of the water
and how much material it erodes? Which is “harder,” rocks or water?
If sand is so easily eroded by water, why are sandbags used to hold
back a flood?
What’s Going On? Water is pulled by gravity to lower and lower levels.
As the water moves, it exerts a force of change, called erosion, upon the
surface over which it travels. Erosion is the process by which pieces of soil
and rock fragments are carried from one location to another.
Try This: Can you build a structure out of sand that the water will not erode
or crash through? Is there a point where the sand stops absorbing water?
Make a course for the water and turn the valve to allow the water to run
down the slope.
Fun Fact: While rock, soil and sand often seem “harder,” water can create
amazing erosion patterns over millions of years – like the Colorado River
carved out the Grand Canyon.
BIG GIANT LEVER
➜ BIG SCIENCE PARK
Inquiry Starters: How much weight can you lift with the help of this lever?
Observe the distance between the ropes and the fulcrum, or pivot point,
of the lever. What relationship do you notice about the distances?
How does this simple machine help you do work?
What’s Going On? That is a real car you are lifting! By using a class one
lever, you can lift a 2,437 pound 1961 Mercury Comet. In a class one
lever, the fulcrum is between the load (the car) and the effort (you).
The distance from the fulcrum affects the amount of work required to lift
the car. Double the distance equals half the effort.
PULLEY CHAIRS
➜ GADGETS
Inquiry Starters: What is the difference
between the three chairs? How many
pulleys make the work of lifting yourself
easiest? What is the relationship between
number of pulleys and ease of work?
Do simple machines always make the
job easier?
Fun Fact: The tension on the cable on the high wire unicycle can support
the weight of an army tank!
What’s Going On? Simple machines,
like pulleys, lower the amount of effort
(force) needed to complete a task.
Work is defined as force times distance.
Simple machines make the job easier, but
you have to work longer to do the job. A
one-pulley system means you pull the length of a rope the same distance
you are lifting yourself (hard work). In a two-pulley system, you lift yourself
with half the force but must pull the rope twice the distance.
HOOP AND STICK/HULA HOOPS
Try This: While at COSI, sign up for a Gadgets Café to invent
something wacky!
Try This: For another great body-on way to experience a class one lever,
ride the High Wire Unicycle on the Mezzanine level. (Please see rules and
regulations at the High Wire Cycle for riding requirements!) Are you strong
enough to do the work? What is the load?
➜ PROGRESS
Inquiry Starters: How can you get the hoops to spin? What is necessary
to keep the spin going? What is momentum and how can you build up
momentum? How can you transfer energy to the hoops?
What’s Going On? Friction is a very important force. Without friction, it
would be very difficult to move. Molecules rubbing together allow you to
slide, grip, stop, and go. By applying a force with the stick or your body,
you transfer energy to the hoop and it spins. Momentum, the mass times its
speed, is built up as you apply more and more spinning, or centripetal force,
to the hoop. Centripetal force causes the hoop to keep spinning outward.
Try This: If the weather allows, take a ride on the Centripetal Generotor in
Big Science Park. (Please see rules and regulations at the Rotor for riding
requirements!) Instead of just observing the forces of friction, gravity,
centripetal force, and inertia, the Rotor applies these forces to you, the
rider! Midway through the ride, the floor drops down, causing the force
from friction to be greater than the force of gravity. These forces stick you
to the wall. But be careful! When the
ride slows down and gravity wins
out again, all these forces may also
cause a wedgie!
Fun Fact: The Rotor spins at the same
speed as a long-play vinyl record
(remember those?).
Fun Fact: Simple machines don’t always make a job easier. Sometimes
they make a job silly! Rube Goldberg machines use as many pulleys,
levers, wheels, screws and other parts as possible to create an interesting
invention. Visit www.rube-goldberg.com for great activities.
BALL LAUNCHER & GRAVITRON WALL
➜ GADGETS
Inquiry Starters: How does the air build up to make the ball shoot out?
Where does the air come from? Will the ball always trace the same path or
can you change variables to get a different result? What happens when the
balls reach the wall? What happens when you use several balls at once?
What’s Going On? Lifting the weight transfers potential (stored) energy to
the weight. As the weight falls, the potential energy is converted to kinetic
(active) energy. The kinetic energy is transferred to the ball as the air
molecules hit the ball, launching it into the air. When the ball reaches
the Gravitron wall, it has high potential energy again. Then gravity really
takes over and the ball starts to drop. As the ball moves downward through
all the contraptions on the wall, it is converting its potential energy to
kinetic energy.
Try This: Observe the ball launcher on the mezzanine level. Does it work the
same way? Keeping gravity and energy in mind, help your children design
their own Gravitron with things you have around your house.
Forces and Motion
Forces and Motion are concepts that thread through many scientific theories and everyday
www.brainpop.com
www.howstuffworks.com
R E S O U R C E S F O R F U RT H E R E X P L O R AT I O N
Continue the fun of forces and motion at home! Check out these resources
and discuss how forces and motion are a part of everything around you!
www.cosi.org
www.sciencespot.net
STRUCTURES (BRIDGE BUILDING)
➜ GADGETS
Inquiry Starters: What forces act upon bridges and buildings? How do
those forces change as the structures become larger? What are some
ways to make your bridge stronger?
A C T I V I T I E S F O R K I N D E R G A RT E N A G E A N D Y O U N G E R
What’s Going On? Gravity is the most important force to remember when
building something. Gravity pulls straight down, but there are always
equal and opposite reactions as the ground pushes back. Building a
strong foundation is essential to keep the structure sturdy, as forces can
come from every direction!
Parents, below you will find fun questions to ask your child as they explore
the little kidspace exhibition area.
Try This: Design a bridge or structure at home out of materials found
around the house. Can your structure support weight? What happens
to your structure when you apply forces, like wind or vibrations from
earthquakes? Make your structure stronger and add forces again!
This is called a “vortex.” What do you notice about the balls? Is anything
touching them? Feel the air coming out the machine. What does the air feel
like? How can the balls stay up in the air? Take a different ball and try to
make it balance in the air. Does it work the same way? Cover up one of the
holes that the air is blowing out. What happens? If you like this exhibit, go
see Newton’s Nozzles in Gadgets and Ball Fountains in Ocean.
FIGURE 8
➜ SPACE
Inquiry Starters: How does the path of the ball relate to the path of a
spacecraft? Does the weight or the size of the ball affect the route it
takes? In space, is the shortest distance between two points a straight
line? What role does gravity play in space, and how can astronauts
use it to their advantage?
What’s Going On? As planets orbit the sun, many forces act upon them.
An object in motion tends to stay in motion at a constant speed and in a
straight line, until an outside force affects it. In space, that force is gravity.
This exhibit allows you to experiment with interplanetary gravity, trajectories,
and “slingshotting”.
Try This: Try placing the ball at different places and exert the same amount
of force on it. Observe how the path changes or stays the same. Now pick
a spot and try again. How does understanding how the ball moves around
the target help you land a spacecraft?
THRUSTERS
➜ SPACE
Inquiry Starters: How do the thrusters respond to the forces you apply
to them? What role does friction play in moving the thrusters?
What’s Going On? Air valves are strapped to the ends of 18-foot swinging
boom arms suspended from the ceiling. Activating these valves creates
action-reaction effects and simulates rocket control in space.
Try This: Pick a position on a thruster’s route (use the glow-in-the dark box
on the ceiling) and try to position the thruster to stop there. How close can
you get it? What factors do you have to take into account that would not
be in place on land? Why is investigating this concept important to space
travel? Go to the Armchair Astronaut area in Space or to Ocean and find
the Remotely Operated Vehicles. Compare and contrast the motion of
all the vehicles.
GO TO THE BRIGHT YELLOW MACHINE
WITH THE BALLS FLOATING ABOVE IT…
FIND THE YELLOW BOX
THAT LOOKS LIKE A FUNNEL…
Can you look down inside of it? What happens if you drop a ball right in?
What happens if you roll a ball in a big circle? What happens if you use
a different ball? Use more than one ball at a time. Where do the balls go?
There are lots of vortexes at COSI! Try the one in Space with balls that
glow in the dark or the one by the Guest Services Center in the Atrium.
GO TO THE WATER ARCADE…
Put on a rain slicker—you may get wet! Sit on a stool and play with the
water squirters. Try to move one of the objects in the arcade. What does it
do? What is moving the object? Can you change the object’s direction?
Move to another squirter and try something else. Do you notice a difference
between the two squirters? Were there any objects the water could not
move? Check out the fountains in Ocean. What can you aim the water at?
TRYATTHIS…
HOME!
P A R E N T ’ S
G U I D E
Try these cool activities at home to learn even more about Forces and
Motion! Work together, adults and kids, to learn and have fun. Try to
find examples of Forces and Motion at home, like your garage door
opener or swing set. It’s amazing how much science is in your house!
MAKE YOUR OWN PENDULUM
Pick a spot for your pendulum. You’ll need
a flat surface for the base and a place to
➜ Length of string
swing from. You can try a kitchen cabinet
➜ Washable marker
handle and the countertop below, or you
➜ Large sheet of paper
can make a tower with toys like Tinker Toys
➜ Tape
or LEGO and use the floor as a base. Tie one
end of the string around the washable maker
and attach the other end to the tower or handle, making sure that the tip
of the marker touches the paper. You may need to tape the paper to the
surface underneath so it stays in place!
MATERIALS NEEDED
Once your pendulum is all set up, pull the bob (the marker) back and let
it swing. Does it move like you thought it would? What pattern does the
marker trace on the paper? What forces are acting on the pendulum?
If the lines the bob produces are wobbly, try attaching the marker
differently. If you push the bob instead of letting it swing, what patterns
appear on the paper? Can you get your bob to trace a circle or a
spiral? What keeps stopping the pendulum?
HOMEMADE RUBE GOLDBERG MACHINE
Before starting, if you have a computer at home,
visit www.rube-goldberg.com for inspiration.
MATERIALS NEEDED
➜ Kitchen gadgets
➜ Tools
➜ String
➜ Rubber bands
➜ Tennis ball or racquetball
➜ Fasteners,
like Velcro or tape
➜ Lots of space!
Find as many wacky objects as you can
around the house. (Make sure you ask
an adult if it is OK to play with these
objects!) Using the tennis or racquetball
as a guide, make the craziest track for
the ball to roll though, fly over, snake
down and just move. How can you
make the ball’s path longer? What
gadget makes the coolest effect? What
forces act upon the ball at each point?
HOW TO USE THIS GUIDE
Experience COSI exhibits in a whole new way by using the
questions, information and activities found in this guide.
Get more out of your visit to an exhibit by making hypotheses,
asking questions and using all your senses to observe the exhibit.
What is going on around it? What do you hear? How does it feel?
Inside you’ll find starting questions (Inquiry Starters), information
(What’s Going On?) and suggested directions on where to go next
(Try This). The “Try This At Home” activities panel will further engage
all the members of your group to continue learning at home.
WHAT IS INQUIRY LEARNING?
COSI’s exhibits are designed according to the principles of
inquiry. The inquiry method of learning engages the learner by
encouraging you to ask questions, make observations, and draw
conclusions. This way, you truly learn about the content and the
processes of science.