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Isaac Newton (1642-1727)

• English physicist andmathematician

• Studied motion, light,and gravity

Newton puts all thepieces together

Newton’s Law of Gravity

• Key idea: Mass• Mass is _________________________

– NOT the same as _____ (to a scientist)– You can be weightless, but never mass-

less

Newton’s Law of Gravity

• Everything with mass pulls oneverything else with mass

• Gravity is always _________• The _____ the object, the ______ the

pull

Newton’s Law of Gravity

F = -G × (Mm/r2)

• M =• m =• r =• G = gravitational constant

= 6.67 × 10-11 m3/s2kg

M

m

r

Newton’s Law of Gravity

F = -G × (Mm/r2)

• Force grows or shrinks with ________________– If you get 2x closer, force is __x _______– If you get 3x farther away, force is __x

_______• Called Inverse-square relation

Newton’s Laws of Motion#1: A body continues at rest or in uniform motion in a

straight line unless ______ _____ ___ ___ _____.

Why doesn’t the soccer ball move on its own?

What causes a soccerball to roll to a stop on the grass?

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Newton’s Laws of Motion#2: The amount of change in a body’s motion is

proportional to the force acting on it, and along thesame direction as the force.

F (_____) = m (____) × a (___________)

If I kick the ballthis way

______________________________

If I kick theball harder,

____________

The more _______ the body,the more _____ you need to

change its motion

Need ________ force to move a bowlingball

Only need _______ force to move aping-pong ball

Newton’s Laws of Motion

#3: When one body exerts a force on asecond body, the second body exerts an_____ and ________ force back on thefirst body.

What’s happening at the moment

when I kick the soccer ball?

Hint: Think about what would happen if you kicked theball really hard with no shoes on.

Gravity Lecture Tutorial:Pages 29-31

• Work with a partner or two• Read directions and answer all questions carefully.

Take time to understand it now!• Come to a consensus answer you all agree on before

moving on to the next question.• If you get stuck, ask another group for help.• If you get really stuck, raise your hand and I will

come around.

The Moon and Earth pull oneach other with _____ strength

and in _______ directions

Earth

Moon

Fg Fg

You and Earth pull on eachother with _____ strength and

in _________ directions

Earth

Fg

Fg

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Wait, I thought I understoodthis stuff! Shouldn’t Earth feelless gravity from me? I’ve got

a lot less mass than Earth!

The more massive the body, the moreforce you need to change its motion

Earth

Fg

Fg

Which one will move more: You or Earth?

a (acceleration) = F (force) m (mass)

Light and Matter:Reading Messages from the

CosmosHow do we experience light?

• The warmth of sunlight tells us that lightis a form of ______

• We can measure the ______, or flow ofenergy over time, of light in units of______

• One _____ is about the amount ofpower used to lift an apple over yourhead in 1 second

_____ of Light

• White light is made up of many different_____

How do light and matterinteract?

• Emission• Absorption• Transmission

– Transparent objects let light through– Opaque objects block or absorb light

• Reflection or Scattering

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Reflection and Scattering Interactions of Light withMatter

What is light?

• Light can act either like a ____ or like a________

• Particles of light are called _________

Waves

A wave is apattern ofmotion thatcan carry_____ withoutcarrying _____along with it

Properties of Waves

• ___________ is the distance between two wavepeaks

• _________ is the number of times per second thata wave vibrates up and down

____ ______ = wavelength x frequency

Light: Electromagnetic Waves

• A light wave is a _______ of electric andmagnetic fields

• Light interacts with charged particles throughthese electric and magnetic fields

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Wavelength and Frequency

wavelength x frequency = ______ __ _____ =_________

Particles of Light

• Particles of light are called photons• Each photon has a _________ and a

__________• The energy of a photon depends on its

frequency

Wavelength, Frequency, andEnergy

λ x f = cλ = , f =c = 3.00 x 108 m/s = speed of light

E = h x f = photon energyh = 6.626 x 10-34 joule x s = Plank’s constant

What is the electromagneticspectrum?

What is the electromagnetic spectrum? Gamma Rays•____ ____ frequency

•____ ____ energy

•Damaging to humans!

•Can only be studied fromspace

•Gamma ray bursts, nuclearreactions

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X-rays

•Still pretty high ______

•Not as bad as ______rays, too much is still bad

•Medical uses

•Can still only be studiedfrom ______

•Gas in galaxy clusters,supernova remnants, or theSun’s corona

Ultraviolet (UV) Light

•Getting closer to visiblelight!

•Too much is still a badthing (____________)

•Visible in supernovaremnants and comingfrom very hot stars

Visible Light

•Light our ____ ___ ___!

•Wavelengths about aslong as bacteria

•About ___ - _____________

•Produced in stars

Infrared (IR) Light•__ _____ in IRlight!

•Beyond the rangeof human sight

•____-____________

•Given off byplanets, some gasclouds, and moons

Radio

•Very wide range ofwavelengths /frequencies

•Subcategories: __, __,__, _______, _______

•The CMB (cosmicmicrowave background)glows in microwaves

EM Spectrum Lecture Tutorial:Pages 45-47

• Work with a partner or two• Read directions and answer all questions carefully.

Take time to understand it now!• Come to a consensus answer you all agree on before

moving on to the next question.• If you get stuck, ask another group for help.• If you get really stuck, raise your hand and I will

come around.