Fantastic Experiments With Forces.pdf

MIND-BLOWING SCIENCE EXPERIMENTS

NA F T

STIC

EXPERIMENTS

WITH



FORCES

WITH

Please visit our website, www .gar ethstevens.com.

o

F

r a free color catalog of all our high-quality books,

call toll free 1-800-542-2595 or fax 1-877-542-2596.

Cataloging-in-Publication Data

Names: Canavan, Thomas.

antastic experiments with for Title: F ces / Thomas Canavan.

Description: New Y ork : Gareth Stevens Publishing, 2018. | Series: Mind-blowing science experiments | Includes index.

Identifiers: ISBN 9781538207 499 (pbk.) | ISBN 9781538207 437 (library bound) | ISBN 9781538207314 ( 6 pack)

Subjects: LCSH: F orce and energy--Experiments--Juvenile literature. | Science--Experiments--Juvenile literature. |

Science projects--Juvenile literature.

Classification: LCC QC73. 4 C317 2018 | DDC 531.113--dc23

Published in 2018 by

Gareth Stevens Publishing

111 East 14th Street, Suite 349



ork, NY 10003 New Y

Copyright © Arcturus Holdings Limited

Author: Thomas Canavan

Illustrator: Adam Linley

Experiments Coordinator: Anna Middleton

Designer: Elaine Wilkinson

Designer series edition: Emma Randall

Editors: Joe Harris, Rebecca Clunes, F rances E vans

Photographs by Shutterstock.

All rights reserved. No part of this book may be r eproduced in any

form without permission fr om the publisher , except by a reveiwer.

Printed in the United States of America

CPSIA compliance information: Batch CS17GS

or further inf : F ormation contact



Gareth Stevens, New Y ork, New Y ork at 1-800-542-2595.

Inside this book you’ll find a whole range of exciting science experiments

that can be performed safely at home. Nearly all the equipment you

need will be found around your own house. Anything that you don’t



e

s

t



n

n

t

C

o

Some Light Reading

...........................................................................

Last Man Standing

.............................................................................

Up to the Water Mark

.........................................................................

The Attractive Balloon

......................................................................

Faling Prices

......................................................................................

Arch Power

.........................................................................................

Low Pressure Affront

........................................................................

Crater Making

kaT e Pen for

No

—

Hey

....................................................................................

a Spin

...........................................................................

Pressure!

............................................................................

The Balancing Forks

..........................................................................

The Last Straw

...................................................................................

Prepare for akeoff T

...........................................................................

Glossary & Further Information

Index

......................................................

..................................................................................................

31

s



...........................................................................

4

.............................................................................

6

.........................................................................

8

......................................................................

10

12

14

........................................................................

16

18

...........................................................................

20

............................................................................

22

..........................................................................

24

26

...........................................................................

28

......................................................

31

32

n

g

i e t

d

a

R

h

i

L

g m

e

o

S

A peli of textbookss i prety heavy to carry

arounds i,nt i’? But can you imagine lifting that

same peli usn igu jst your breath? Itseems easy

enough to lift a sheet of paper or a feather with

u jst your breath b,ut somethn ig as heavy as a

Half f ll a w STEP ONE

at er bottle

stack of books? Is there a scientifc trick waiting

to be learned?

Half f ll a water bot tle STEP ONE

1

2

Half f ll a wat STEP ONE

er bottle

Half f ll a water bot tle STEP ONE

Half f ll a wat STEP ONE

er bottle Half f ll a w Half f ll a w

STEP ONE STEP ONE

at er bottle a t er bottle

a

T

pe the handle and open end of

Place the bag close to the edge

the bag shut, leaving just enough

of the table, with the taped end

Half f ll a water bot tle STEP ONE

space to slide a straw inside it.

facing you.

Half f

Half f

ottle

ll a water bot tle STEP ONE

4

ll a water b

5

STEP ONE

YOU WILL NEED

Half f

ll a w

STEP ONE

a

ter bottle

d

a

Half f

ll a wa

STEP ONE

t

er bottle

Half f

ll a w

STEP ONE

at

er bottle

Half f

ll a wat

STEP ONE

er bottle

ll a wat

ll a wat

STEP ONE

STEP ONE

er bottle

er bottle

Half f

ll a water bot

tle

STEP ONE

ll a w

STEP ONE

a

t

er bottle

ll a water bot

tle

STEP ONE

6

3 hardbound •

Masking tape •

Plastic drinking straw •

A small plastic bag •

T able •

books (about 200

ll a water b

Half f

STEP ONE

ottle

Half f

STEP ONE

ottle

Half f

Half f

Half f

ll a water b

Half f

g i

n









pages each)

2

3

Pile the books on the bag.

ll a w Half f

u o Y ’ve just demonstrated P ascal’s Law , first noted b y French

scientist Blaise P ascal in the seventeenth century . It deals with

fluids

, the term that scientists use to describe both

W liquids

and

gases

O

H

if an outside

force

S T

I

O

D

E

applied to an enclosed fluid (the air inside the bag).

The force is tr ansmitted equally thr oughout the fluid. Y ou

W

O

K

?

R



might think that your breath is a small force, but it is

pressing equally all across the bag. That multiplied force

then becomes strong enough to lift the books!

WHAT



HAPPENS

TIP! TOP

Make sure that the

straw fits snugly ins

. F I ..?



ide the

in all directions.

opening of the bag,

with no

That’s because the force of

ou might even find i gaps. Y

t

your finger’s

easier to slide the s

traw in



equally through the air inside the balloon.

first and then tape

the

With enough force, it will burst!

. end of the bag shut

demonstrated P ascal’s Law , first noted b y French

ascal in the seventeenth century . It deals with

fluids

, the term that scientists use to describe both

liquids

and

gases

if an outside

. The law describes what happens

force

(in this case, your breath) is

applied to an enclosed fluid (the air inside the bag).

The force is tr ansmitted equally thr oughout the fluid. Y ou

might think that your breath is a small force, but it is

pressing equally all across the bag. That multiplied force

then becomes strong enough to lift the books!

Maybe you’ve done a

variation of this

WHAT

in reverse. experiment —



HAPPENS

If you poke

. F I ..?

a blown-up

balloon, you’ll

see it bulge out

in all directions.

That’s because the force of

your finger’s

pressure

has been spread

equally through the air inside the balloon.

With enough force, it will burst!

R

E

A

L

-

L

I

F

E

SCIENCE

n n

i d

t a

S a M

n

s t L

a

Here’s a chance to scientifically define

the term “pushover ” . Which of these three

similar cartons is the easiest to knock down?

uoY might be surprised at the result!

1

2

”

4

Fill one carton with water ,

-fHalfill a second, replace the

screw the cap back on and

cap and mark it “Half ” .

mark it “F ull.

5

g

YOU WILL NEED



n

g

i

3 empty fruit juice

•

d



cartons with

screw‑on caps

W ater

•

F elt‑tip pen

•

T able

•



Ruler

•

•

2

3

Screw the cap back on to

the third carton and mark

”it “Empty .

5

6

Note pad

This experiment is all about

any object that repr esents the aver age location of its

u o Y can imagine all of the object’s mass being concentrated

at that point. In practical terms, the center of mass

W

determines how stable an object is. If it remains

O

H

above the object’s base of support (like the base of

S T

I

O

D

E

the cartons), then the object remains stable. The

cartons was — and empty center of mass of the full —

W

O

K

?

R



about halfway up the carton. But the half‑full carton’s

center of mass was in the lower half because the top

half (filled with air) had less mass.



TIP! TOP



Make sure that you



have the measuring





ing stick actually touch

re all three cartons befo

you move them.

WHAT



HAPPENS

This experiment is all about

center of mass

u o Y can imagine all of the object’s mass being concentrated

at that point. In practical terms, the center of mass

determines how stable an object is. If it remains

above the object’s base of support (like the base of

the cartons), then the object remains stable. The

cartons was — and empty center of mass of the full —

about halfway up the carton. But the half‑full carton’s

center of mass was in the lower half because the top

half (filled with air) had less mass.







mass

any object that repr esents the aver age location of its



the point in —

.

r k

a

M

e

r

a

t

W t

h

e t o

p

U

Wek now that firefighters use hoses that work

under enormous pressure to send the water

high up into tall buildings, great distances —

for example. But you don’t need special

equipment to understand how water behaves

when it’s under pressure.

1

2

0 1 2 3 4 5 6 7 8 9 01 11 21 31 41 51

Fill each bottle completely with

Ask an adult to make a hole as

tap water .

wide as the pencil in the first

bottle, about 2 inches (5 cm)

from the top. Ask a friend to plug

the hole with their finger .

4

5

YOU WILL NEED



r k

a

M

e

r

t 3 empty 2‑liter plastic

•

bottles

W ater

•

Sharp pencil or nail

•

aPper

•

Ruler or tape measure

•

•

3

2

0 1 2 3 4 5 6 7 8 9 01 11 21 31 41 51

Repeat step 2 f or the second

bottle, but with the hole about

halfway down.

6

3 f r i e n d s

One of Sir Isaac Newton’s great observations was that a force

is a combination of something’s mass and

water bottle, the water was falling with the same acceleration

because of the force of

gravity

W

O

H

three bottles was how much mass was bearing

S T

I

O

D

E

down on the water by each hole. The bottom

hole had nearly a full bottle of water weighing

W

O

K

?

R



down on it. All that extra mass meant mor e

force, which is why this bottle shot its water

the farthest!



TOP TIP!

Things can ge

t a



little messy, s

o make

sure you do t his

experiment o utside!

WHAT

uoY ’ve worked out

One of Sir Isaac Newton’s great observations was that a force

is a combination of something’s mass and

acceleration

water bottle, the water was falling with the same acceleration

because of the force of

gravity

. The big difference between the

three bottles was how much mass was bearing

down on the water by each hole. The bottom

hole had nearly a full bottle of water weighing

down on it. All that extra mass meant mor e

force, which is why this bottle shot its water

the farthest!



R

E

A

L

-

. In each



o a

l

o l

B i

c

v

e

t t

a

t

r

e A

h

T

u o Y want guests to stcik around at your brithday

party b ,ut plastic cups sticking to a party baolon?

Thast’ not he rg ihtd iea .How did those cups end

up stuck to the baloon in the first place? A party

game gone wrong? Tm i e ton ivestg iate.

1

4

2

Blow the balloon up until it’s

Pinch the balloon shut, but

about the size of a grapefruit.

don’t tie it.

5

n

YOU WILL NEED



o a

l

n

o l

B

A party balloon

•



At least six light

•

plastic cups

•

3 2

Rub some water on the rims

of six plastic cups.

5

6

Some water

This experiment is an exploration of air pressure and

surface tension

. First, the wet surfaces of the rims helped

the cups stick to the surface of the balloon. This is because

of a force called surface tension. Each cup contained air. As

W

O

H

you inflated the balloon more, the surface of the balloon

S T

I

O

D

E flattened a little, so that the trapped air took up

volume

more

W

O

(space) in the cup. This

K

?

R

meant the trapped air lost some of its



pressure. But the outside air pressure

remained the same, forcing the cups

against the balloon.

WHAT



HAPPENS

. F I ..?

TIP! TOP

It’s easier to do this



riend. experiment with a f

ps while They can add the cu

n. you blow the balloo

R

E

A

L

-

L

I

F

E

SCIENCE

This experiment is an exploration of air pressure and

surface tension

. First, the wet surfaces of the rims helped

the cups stick to the surface of the balloon. This is because

of a force called surface tension. Each cup contained air. As

you inflated the balloon more, the surface of the balloon

flattened a little, so that the trapped air took up

volume

more

(space) in the cup. This

meant the trapped air lost some of its

pressure. But the outside air pressure

remained the same, forcing the cups

against the balloon.

Lots of science

experiments work if you

“scale up” or “scale down. ”

WHAT

This means using larger or

HAPPENS

smaller amounts of ingredients

. F I ..?

to achieve the same result

on a different scale. Can you

imagine trying this experiment at

the seaside, using a beach ball

and some plastic buckets?

Where else can you imagine

performing a version of

this experiment?

ce

s

ri

P ng lli

a

F

A playing card, a coin, and an unexpected twist?

uoY r friends might mistake this mind-blowing

experiment for magic! F ollow these steps to wow

your audience with the wonders of

inertia

!

1

Lay the card across the rim

of the glass. It doesn’t have to

cover the entire opening.

Place the coin in the middle of

the card, making sur e that it’ s

well within the opening below

the card.

3

Curl your index finger back



YOU WILL NEED

Drinking glass

•

d Playing car

•

Coin •

inertia

!

2

Lay the card across the rim

of the glass. It doesn’t have to

cover the entire opening.

Place the coin in the middle of

making sur e that it’ s

well within the opening below

4

your index finger back



This experiment is an excellent demonstration

of Newton’s First Law of Motion, which states

that an object will stay at rest or will continue moving

unless an outside force acts on it. That “unwillingness

W

O

H

to move” (or the unwillingness to slow down if it’s already

moving) is called inertia, and it increases as something

S T

I

O

D

E

gets more mass. If you moved the card slowly , the force

of that movement wouldn’t overcome the force of the

W

O

K

?

R



friction holding the coin in place. The much greater force of the

flick overcomes the friction, so the object with less inertia

(the less massive card) moves, but the coin doesn’t.

WHAT

HAPPENS

. F I ..?



TIP! TOP

This classic magic trick uses the

rks This experiment wo

same principle as your experiment, and

best with a clear gla

ss.

nothing breaks! But it takes a lot of

Hearing the “ping”

practice to master this trick, so

when the coin falls

in

it’s best to stick to coins and

is extra satisfying!

playing cards for now .

This experiment is an excellent demonstration

of Newton’s First Law of Motion, which states

that an object will stay at rest or will continue moving

unless an outside force acts on it. That “unwillingness

to move” (or the unwillingness to slow down if it’s already

moving) is called inertia, and it increases as something

gets more mass. If you moved the card slowly , the force

of that movement wouldn’t overcome the force of the

greater force of the



flick overcomes the friction, so the object with less inertia

(the less massive card) moves, but the coin doesn’t.

Can you imagine

WHAT

setting a table with

HAPPENS

crystal glasses and fine

. F I ..?

china, and then quickly

whisking off the tablecloth

from beneath everything?

This classic magic trick uses the

same principle as your experiment, and

nothing breaks! But it takes a lot of

practice to master this trick, so

it’s best to stick to coins and

playing cards for now .

r

e P

o

w c h A

r

uoY and your friends can build a medieval

cathedral in your kitchen in a matter of minutes or at least —

demonstrate one of the most important engineering features that

has kept cathedrals standing for centuries. It’s all about arches.

1

2

Have two of your friends stand

Ask them each to take one step

facing each other , wearing just

backwards.

their socks.

4

5

YOU WILL NEED

4 f r i e n d s

•

•

2

3

Ask your second pair of friends

to sit on the floor behind the first

our friends sitting down . Y pair

should wear shoes. The sitting

friends’ backs should touch the

standing friends’ calves.

6

A slippery floor

The seated pair of friends should have felt the f or ce of the

others’ heels digging into them. That’s because the standing

pair created an arch, and an arch is an important way of

transferring forces. It takes the force of its own weight and

W

O

H

any weight pressing on it (like the roof of a

S T

I

O

D

E

building) and transfers it into an outwar d

and downward force along its curves.

W

O

K

?

R

That’s the force that the seated pair

of friends can feel, pressing out from

the heels of the two friends standing.

Engineers call the supports at the base of

arches (like the seated pair) buttresses.



TOP TIP!

This experiment works

best if the sitting pair

of friends keeps their

shoes on to act as brakes

against sliding (and to

concentrate the force



on their backs).

WHAT

The seated pair of friends should have felt the f or ce of the

others’ heels digging into them. That’s because the standing

pair created an arch, and an arch is an important way of

transferring forces. It takes the force of its own weight and

any weight pressing on it (like the roof of a

building) and transfers it into an outwar d

and downward force along its curves.

That’s the force that the seated pair

of friends can feel, pressing out from

the heels of the two friends standing.

Engineers call the supports at the base of

arches (like the seated pair) buttresses.



n

f

t

o

f

r

e A u

r

S r

e

s w

L

P

o

How much does a plastic bag weigh? Could

you pick one up? If you think this is a trick

it is! Y ou can use some simple science — question

to “lock” a plastic bag inside a bowl. At least,

that’s how it will feel when you try to pick it up!

1

2

Open the

bag and use

it to line the

inside of

the bowl.

Press it snugly down and fold the spar e plastic

over the rim of the bowl.

3

4

YOU WILL NEED



n

f

t

o

f

r

r e kitchen gLa

•

A

mixing bowl



Plastic bag (its

•



mouth must fit

over the bowl)

Lar ge rubber band

•

•

2

Press it snugly down and fold the spar e plastic

over the rim of the bowl.

4

1 or more friends

ou’ve just demonstr Y ated Boyle’s Law . This scientific

principle is all about volume and pressure. It tells us that

if the same amount of gas (measured in the amount of

molecules

) is forced into less volume, then its pressure

W increases. So, if the v olume incr eases, the pr essure goes

O

H

down. That’s what happens here when your friend

S T

I

O

D

E

pulls on the bag. Even a little tug increases the

W

volume and lower s the air pr essure inside the

O

K

?

R



bag. But the air pressure all ar ound you hasn’t

changed, and it wins the battle of the pressures,

holding the bag down.





TIP! TOP

or metal

matter w It doesn’t

hether

c a m i c e r

you use a



ong as it’s bowl, as l

o

Y

u don’t wa

. sturdy

ength nt the str

d to sque of the ban

eze the

bowl out

of shape.

ou’ve just demonstr Y ated Boyle’s Law . This scientific

principle is all about volume and pressure. It tells us that

if the same amount of gas (measured in the amount of

molecules

) is forced into less volume, then its pressure

increases. So, if the v olume incr eases, the pr essure goes

down. That’s what happens here when your friend

pulls on the bag. Even a little tug increases the

volume and lower s the air pr essure inside the

bag. But the air pressure all ar ound you hasn’t

changed, and it wins the battle of the pressures,

holding the bag down.



or metal

g i n

k r

M

a

t e

ra

C

uoY ’ve seen images of

c r a t e r s

on the surface of

the Moon and some planets, such as Mercury .

Have you ever wondered what creates them, or

why they’re not all the same size? Time for some

in your kitchen! space exploration —

1

2

Pour flour into the tray and

shake it until you have an

even layer on the base, about

3 inches (8 cm) thick.

12 inches

4

5

(30 cm)

YOU WILL NEED

Metal baking tray

•



Hot cocoa mix or

•

instant coffee

on the surface of F

•

lour

Spoon

•



3 playing marbles

•

(of different sizes)

•

Ruler

12 inches



3

2

(30 cm)



12 inches

6

(30 cm)

Newton’s Second Law of Motion deals with force, the mass

of an object, and its acceleration. Acceler ation isn’t always

it can also be about slowing down. about speeding up —

That’s what these three marbles ar e doing. They’e each r

W

O

H

slowing down fr om falling speed to zer o, so the

S T

I

O

D

E acceleration is the same. The big differ ence is in

their size, or mass. And Newton’s Law says

W

O

K

?

R

that F orce is made up of Mass times



Acceleration (F=MA). So the bigger the

mass in this exper iment, the lar ger

the force, and the bigger the crater!



TOP TIP!

If you use ins

tant

coffee, it’s bet ter if you

can use powd er and



not granules.

WHAT

HAPPENS uoY can see and

Newton’s Second Law of Motion deals with force, the mass

of an object, and its acceleration. Acceler ation isn’t always

it can also be about slowing down. about speeding up —

That’s what these three marbles ar e doing. They’e each r

slowing down fr om falling speed to zer o, so the

acceleration is the same. The big differ ence is in

their size, or mass. And Newton’s Law says

that F orce is made up of Mass times

Acceleration (F=MA). So the bigger the

mass in this exper iment, the lar ger

the force, and the bigger the crater!





R

E

A

-

n

i

p

S

r

f o

n a

P

e

k e

a

T

How do you get a pen to stay upright without

hould c inga it?n Y simply tuck it into a pencil

or you coud l use a bti of sceince— to keep

holder

it balanced on nothing more than its own tip!

1

2

Spin it with a quick twist of your Hold the pen upright, so that

fingers, as if you were getting a its tip just touches the floor



spinning top started. The pen will or table.

fall over .

4

5

YOU WILL NEED

n

i

S

p

Ballpoint pen

•

DVD or CD

•



Smooth floor or

•

lar ge table

Sticky tack

•

•

Ruler

3

0

1

2

3

4

5

6

7

8

9

0 1

1 1

2 1

3 1

4 1

5 1

2

aW r p a piece of sticky tack (about

twice the size of a pea) ar ound

the pen. It should be about 1 inch

(3 cm) up from the tip.

6

u o Y just demonstrated a scientific principle called

angular

momentum

. Momentum describes the strength

of a moving object. It’s a combination of its mass and

W its

O

H

velocity

. A baseball bat has more momentum than a

S T

I

O

D

E acrd board tube swung at the same speed because it

has more mass. Angular momentum describes the

W

O

K

?

R

strength of spinning objects. It also multiplies mass b y



velocity , and multiplies that b y the

sticky tack to the pen added mass, and the width of the DVD

lengthened the radius. The angular momentum incr eased, and

the pen stayed upright!



WHAT

HAPPENS

TIP! TOP



Before you spin the

. F I ..?

pen

ld it the second time, ho

or and upright near the flo

sticky tack, because a record

make sure that the

DVD is

is heavier than a DVD. The angular



. parallel to the floor

momentum would increase even more,

Adjust it if it’s not.

and the pen would spin even longer.

u o Y just demonstrated a scientific principle called

angular

momentum

. Momentum describes the strength

of a moving object. It’s a combination of its mass and

its

velocity

. A baseball bat has more momentum than a

acrd board tube swung at the same speed because it

has more mass. Angular momentum describes the

strength of spinning objects. It also multiplies mass b y

radius

that b y the

. Adding the DVD and

sticky tack to the pen added mass, and the width of the DVD

radius. The angular momentum incr eased, and

What if you hunted

around in your

WHAT

parents’ music

HAPPENS

collection and found a

. F I ..?

vinyl LP record? Y ou could

do the same experiment,

but you’d need a bit more

sticky tack, because a record

is heavier than a DVD. The angular

momentum would increase even more,

and the pen would spin even longer.

R

E

A

L

-

L

I

F

E

SCIENCE

e s

r u

e s

r o

P y — N

e

H

Just how hard it is it to blow a couple of

balloons away from each other? Pretty easy,

unless science stands in your wa . . . you’d think y.

uoY ’ll huff and you’ll puff, but you’ll wind up

winded unless you read up on pressure!

1

2

Cut two pieces of string, each

Rusnom w dcoe laentor w sdly l

about 20 inches (50 cm) long.

pouelsr th ana nic h(25c m . )

neoati B ocbhow lnaul.htp e

obolhnatelns m itd .

4

5

!

YOU WILL NEED

e

!

r

2 balloons

•

u

2 high‑backed chairs

•

St r i n g

•

Scissors

•

Ruler

•

Wom a tap ater fr

•

Empty paper towel roll

•

•

2

3

Tie a string to each balloon

and tie the other end of each

string loosely around the

broom handle.

5

6

oom A br

u o Y ’re supplying the force (your breath) to speed up a channel

begins to or any other gas or liquid of air. And when air — —

move faster, it loses pressure. Remember that air pressure

is all around us, pushing in with a force of 14.7 pounds per

W

O

H

square inch (1 kg per square cm). That force remains the

S I

O

D

T

E

same for all of the air surrounding the balloons, except

for the fast‑moving channel that you’ve created. That

W

O

K

?

R

faster‑moving air has less pressure, meaning

it doesn’t push so har d against the balloons.

That’s why they get pushed together.

WHAT

HAPPENS

. F I ..?

Poke a hole through

the bottom of a

paper cup and stick a

drinking straw through,

plugging up any gaps

with plasticine. Rest

u o Y ’re supplying the force (your breath) to speed up a channel

begins to or any other gas or liquid of air. And when air — —

move faster, it loses pressure. Remember that air pressure

is all around us, pushing in with a force of 14.7 pounds per

square inch (1 kg per square cm). That force remains the

same for all of the air surrounding the balloons, except

for the fast‑moving channel that you’ve created. That

faster‑moving air has less pressure, meaning

it doesn’t push so har d against the balloons.

That’s why they get pushed together.

WHAT

HAPPENS

. F I ..?

Poke a hole through

the bottom of a

paper cup and stick a

drinking straw through,

plugging up any gaps

with plasticine. Rest

k

s

o

F

n g

c i a

n

l

a

e B T

h

How good is your sense of balance?

This experiment uses a little bit of science

to pull off a trick that looks like magic.

The forks seem to be floating in mid-air,

but in fact they are just balanced really well! —

1

4

2

Stick one of the toothpicks

Push and “weave ” the forks

into a hole in the salt shaker

together so that their tines

so that it stands upright,

overlap. They should form an

like a flagpole. Hold the f orks

“x” shape, which you can balance

upright with their curved tines

on your finger beneath the

pointing at each other .

crossed tines.

5

r

k

YOU WILL NEED

s

o

r

F



2 identical

•

metal forks

2 toothpicks

•

•

2

3

e

F

ed the other toothpick through

the first gap of the underside of

the tines, then through the first

gap of the other fork’ s tines.

Sturd y salt shaker

Of course, this w onderful display is not as

impossible as it looks. It relies on the center of

mass. Remember, this term refers to the “middle

point” of an object, or collection of objects so there’s —

W

O

H

an equal amount of mass on either side.

S

Here, the center of mass is at the end of the toothpick

T

I

O

D

E

that was stuck into the forks. Equal amounts of mass

W

O

K

press in on it from all sides, keeping it secure. Even

?

R



the force of gravity is “funneled” into this point, which is

why people sometimes refer to the center of mass as the

“center of gr avity .”

TIPS! TOP

It’s easier to press

ter the forks on a coun

as you weave them

Of course, this w onderful display is not as

impossible as it looks. It relies on the center of

mass. Remember, this term refers to the “middle

point” of an object, or collection of objects so there’s —

an equal amount of mass on either side.

Here, the center of mass is at the end of the toothpick

that was stuck into the forks. Equal amounts of mass

press in on it from all sides, keeping it secure. Even

the force of gravity is “funneled” into this point, which is

why people sometimes refer to the center of mass as the

“center of gr avity .”



TIPS! TOP

It’s easier to press

ter the forks on a coun

as you weave them

together.

Arrange about

a

w

t r



S a

s

t e L T

h

uoY ’ve just had a long bike ride and you’ve come

home thirsty. Look! Someone’s made a cool drink

for you, complete with a straw. Ahhh, just what

you need. Y ou take the straw in your mouth,

nothing! What’s going on? . . begin to suck, and .

1

2

See whether the straw fits

Ask an adult to make a hole in the

through the hole. If not, ask the

center of the lid using a hammer

adult to widen the hole with

and nail.

the nail.

4

5

YOU WILL NEED



Glass jar with

•

screw‑on lid

Plastic drinking straw

•

Hammer

•

Nail

•

P oster putty

•

•

2

W ater or other drink

3

e

F

ed the straw through the lid

so that it will almost reach the

bottom of the jar when the lid

goes back on.

3

4

Fill the jar about

drink and screw the lid back

⁄

full with a

Sucking through a straw isn’t so much about pulling (sucking)

as it is about pushing. Air does the pushing, thr ough the

force known as air pr essure. Normally , you suck in thr ough

which reduces the pr — essure inside your mouth. the straw

W Meanwhile, the air all around the drink is pushing down

O

H

on the top of the liquid in the glass. That pressure is

S T

I

O

D

E

greater than the r educed pr essure in your mouth, so

W

the drink gets pushed up the straw .

O

But if you cover

K

?

R



the drink completely , that outside air can’t reach the

so you can’t get any drink. . . liquid to push down on it .

WHAT

HAPPENS

. F I ..?

it with putty. Blow hard into the

straw and then stand back. As soon

as you stop blowing, water comes

rushing out of the straw! Y our

blowing increased the pressure

of the air inside the bottle so

that it was greater than the air

Sucking through a straw isn’t so much about pulling (sucking)

as it is about pushing. Air does the pushing, thr ough the

force known as air pr essure. Normally , you suck in thr ough

which reduces the pr — essure inside your mouth. the straw

Meanwhile, the air all around the drink is pushing down

on the top of the liquid in the glass. That pressure is

greater than the r educed pr essure in your mouth, so

the drink gets pushed up the straw .

But if you cover

the drink completely , that outside air can’t reach the

so you can’t get any drink. . . liquid to push down on it .

WHAT

uoY can try this

HAPPENS trick the opposite

. F I ..?

way around. Stick

a straw in the

mouth of a half-full

bottle of water and seal

it with putty. Blow hard into the

straw and then stand back. As soon

as you stop blowing, water comes

rushing out of the straw! Y our

blowing increased the pressure

of the air inside the bottle so

that it was greater than the air

pressure outside.

•

f o

f

e

k r

a T

f o

e

a ep

r •

P

r

•

•

80 feet (25

How many times have you heard people

say, “W ell, it’s not rocket science, is it?”

•

2 pieces of

This is a great experiment that really is

about rocket science! Find a large space

•

outside to conduct this experiment and get

•

ready to say, “Mission accomplished!”

•

1

2

80 feet (25 m)

Tie the fishing line between two Thread the two lengths

strong objects, such as tr ees or of drinking straw on the

tall fence posts. Make sur e the

fishing line.

line is taut.

4

5

YOU WILL NEED

2 long, slim balloons

•

f o

f

e

k

Scissors

•

Ruler

•



•

80 feet (25 m) of clear



fishing line

•

, 2 pieces of drinking straw

each 1 inch (3 cm) long



1 empty 1‑liter plastic

•

bottle

Masking tape

•

•

A f r i e n d

3

2

1 inch

(3 cm)

80 feet (25 m)

Cut a ring of plastic 1 inch (3 cm)

wide from the middle of the

plastic bottle.

5

6



7

8

Have your friend attach each balloon to a drinking

Let go of the balloon and watch your rocket zoom

straw (which are fr ee to slide along the line). Pull the

along the line!

balloon combination to the end of the line.

9

Partway down the line, the “first stage” ( or second

inflated balloon) should disconnect and fall behind.

8

Let go of the balloon and watch your rocket zoom

along the line!

Be careful when

hanging up taut

fishing line.

People may not

see it and hurt

themselves.



TIPS! TOP



When you walk the





rocket back to one e

the line, make sure

ends of the balloon

nd of

the pinched

are pointing

ocket will backwards, so the r

go forwards!

This experiment w

orks best

if the fishing line is

very taut

and also level. This

reduces

ack, friction along the tr

letting the stages

. travel further

WHAT

If you had

HAPPENS enough friends

helping you, do

. F I ..?

you think you could

build a three-stage





Glossary

acceleration



A

gravity

change in speed.

The for ce that causes all

objects to be attracted to each other .

center of mass

The point that has the

inertia

mass of an object evenly distributed

around it, also called the center of

Staying unchanged until

changed by an external force.

gravity or balancing point.

liquid

ceramic

Clay that has been baked and

A substance that flows freely

but keeps the same volume.

become hard.

mass

crater

A large bowl-shaped hole in

A measure of how much matter

something contains.

the ground, made by an explosion or

meteor

A small rock or other

meteorite.

substance that enters our atmospher e

fluid

A substance that has no fixed

from outer space.

shape and can be moved by pressure.

molecule

force

The strength of a particular

substance, such as oxygen, that has all



energy at work.

gas

the properties of that substance.

momentum

A substance that can expand to fill

any shape.

object moves.

Further lnformation

Books to read

Experiments with F orces

Mind W orces and Motion ebs: F

Super Science: F eel the F orce

The smallest unit of a

by Anna Claybourne (Windmill Books, 2016)

by Anna Claybourne (W ayland, 2016)

om Adams and Thomas Flintham (T by T emplar , 2011)

The amount an

gravity

predict

The for ce that causes all

objects to be attracted to each other .

o

T

guess what will happen in

the future as a r esult of an action.

inertia

pressure

Staying unchanged until

changed by an external force.

A physical force acting on

or against an object by something in

contact with it.

liquid

A substance that flows freely

radius

but keeps the same volume.

The distance from the center

of a circle to the edge.

mass

A measure of how much matter

reaction

something contains.

Something that happens as

a result of an action.

meteor

A small rock or other

substance that enters our atmospher e

surface tension

from outer space.

molecules on the outer layer of a

Afo rce that binds

liquid together .

molecule

The smallest unit of a

velocity

substance, such as oxygen, that has all

the properties of that substance.

momentum

object moves.

by Anna Claybourne (W ayland, 2016)

and Thomas Flintham (T emplar , 2011)

The speed of something in

a specific direction.

The amount an

volume

substance takes up inside a container .

The amount of space a

x

e

d

n

I

A

G

acceleration 9, 19

gases 5, 17 , 23

air pr essur e 11, 17 , 27

gravity 9, 25

arches 14, 15

I

atmosphere 19

inertia 13

B

balloons 10, 11, 22, 23, 28,





29, 30

L

liquids 5, 23

bicycle 21

books 4, 5, 15

M

Boyle’s Law 17

mass 9, 13, 19

Mercury 18

C

meteors 19

car 5, 13

momentum 21

center of gravity 25

Moon 18, 19

center of mass 7 , 25

crater 18, 19

N

Newton, Sir Isaac 9

E

Newton’s First Law

Earth 27



Newton’s Second Law



of Motion 13



G

P

gases 5, 17 , 23

Pascal, Blaise 5

gravity 9, 25

Pascal’s Law 5

planets 18

I

S

inertia 13

skyscrapers 23, 25

L

space rocket 30

liquids 5, 23

surface tension 11

swimming 9

M

mass 9, 13, 19

V

Mercury 18

velocity 21

meteors 19

volume 17

momentum 21

W

Moon 18, 19

water 8–9

N

weather 27

Newton, Sir Isaac 9

Newton’s First Law



Newton’s Second Law



of Motion 13



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