What is Energy?

Energy is the ability to do work, cause things to happen and

make changes.

PBS NOVA Now - Energy

How do weuse energy?

Examples of Potent ial and Kinet ic Energy

When the ba ll is not moving it ha s potent ia l ener gy.

As it r olls down the hill it loses potent ia l ener gy a nd ga ins kinet ic ener gy.

Potent ia l Ener gy Examples:● A yo-yo in your hand● A spr ing tha t is compr essed● A bike a t the top of a hill

Kinet ic Ener gy Examples:● The motion of the planets

or bit ing the sun● Running, hopping, skipping● A skydiver jumping out of a

plane

What is potent ial energy?

What is kinet ic ener gy?

Ther e a r e many for ms of ener gy but they can a ll be put into two ca tegor ies:

Potent ia l Ener gyPotent ia l Ener gy is stor ed ener gy a nd the ener gy of posit ion.

Kinet ic Ener gyKinet ic ener gy is the motion of wa ves, elect r ons, a toms,

molecules, substa nces, a nd objects.

Chemical Radiant

Mechanical Thermal

Nuclear Motion

Gravitational Sound

Electrical

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Energy Exper imentPotentia l vs. Kinet ic Ener gy:● If we hold a ba ll 20 cm above the floor does it have the same potent ia l

ener gy a s a differ ent ba ll?● Tr y it !

○ Find your pa r tner and choose two differ ent types of ba lls○ Tr y dr opping a ba ll 20 cm off the floor○ Next , t r y dr opping another ba ll 20 cm off the floor

■ What happened?■ Use a r uler to deter mine the height fr om which you a r e dr opping the

ba lls■ Recor d the height of the bounce

Ball Bounce Exper imentMake a table on your paper to r ecor d your r esults.

Type of Ball Starting Height (20 cm) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

Ball #1 Bounce Height (cm)

Ball #2 Bounce Height (cm)

When you a r e done, t r ansfer your infor ma tion to a Google Slides pr esenta t ion. You may make your own or sha r e it with your

pa r tner . We will add to it next week.

Height of Ball vs. Ball Bounce

Ball Bounce Exper imentMake a table on Google Slides to record your results.

Type of Ball Starting Height (20 cm) Trial 1 Trial 2 Trial 3 Trial 4 Trial 5

Ball #1 Bounce Height (cm)

Ball #2 Bounce Height (cm)

After completing the table try this: http:/ / fr eezer ay.com/ fla shFiles/ bouncingBa ll.htm

Height of Ball vs. Ball Bounce

Where does energy come from?

Exper iment :Wha t will happen to the temper a tur e of the wa ter in the pan if we leave it in the sunlight for 45 minutes?

The Coiled Snake

● Hold the sna ke by the st r ing over a ca ndle or light bulb.

● As the light bulb hea ts up, the sna ke should spin.

Explanat ion: When the candle burns, two forms of energy are released, heat and light energy. The heat causes the air to r ise up, which in turn makes the snake spin around. (The snake does not move up because the coiled shape of the snake allows the heat to r ise through the middle and spin the snake.)

Class discussion: The energy we need comes from the food we eat . The energy required to turn the pedals of a bicycle comes from the person r iding the bicycle. Cars and t rucks get their energy from gasoline. Some homes are heated using oil or natural gas or f irewood. When designing heat ing and cooling systems, engineers study thermal energy and how it creates air movement. They place heat vents and radiators low, near the f loor because they know that hot air r ises. As hot air r ises it mixes with the exist ing room air , prevent ing "cold" spots and making the space more comfor table. The same is t rue for cool air vents that are placed high, near the ceil ing. The cool air sinks, evenly mixing with the exist ing room air .

Item that uses energy: We know it uses energy because…...

Source of energy for this item:

Energy Detect ives1. What we know:● We know tha t ener gy gives off hea t or light .

● We know tha t ener gy causes movement .

● We know tha t ener gy ______________________________________

2. Wha t we found:

What are renewable energy resources?

What a r e nonr enewable ener gy r esour ces?

Where does energy come from?Natural energy sources: food, water , plants, t rees,

gravity, sun, fossil fuels, uranium, plutoniumWays that humans have harnessed or conver ted natural

energy sources: hydroelectr ic dams, coal/ oil power plants, nuclear power plants, wind turbines, solar panels, etc.

How do we get energy into our homes?

The sun pr oduces light ener gy

Pla nts tur n the light ener gy into chemica l

ener gy

Pla nts a r e fossilized a nd compr essed into fossil fuels such a s

coa l a nd oil

Fossil fuels a r e bur ned in power pla nts to pr oduce electr icity for our

homes a nd businesses

What are sources of energy?Renewable Nonr enewable

How do Solar Panels Work?Sola r Panels a r e made up of photovolta ic cells or PV cells.

1. When sunlight hits the cells the photons cause the r elea se electr ons in the panel. This cr ea tes a cur r ent or flow of elect r ons t r avel down wir es to an inver ter wher e they a r e changed fr om DC cur r ent to AC cur r ent .

Vocabulary ● Ener gy

● Renewable

● Nonr enewable

● Sola r

● Wind

● Fossil fuels

● Potent ia l ener gy

● Kinet ic ener gy

Slinky Experiment*Draw this table on your notes page

Type of Wave What does it look like?

Longitudinal

Transverse

Slinky Waves -Waves a r e cr ea ted by vibr a t ions. Vibr a t ions a r e the sour ces of sounds.

• On your sketch note, dr aw pictur es of wha t you see happening with each type of wave. • Which way do the waves move? • Wha t happens when the “wave” hits the end of the slinky? • Can you think of other places wher e you see waves?

Slinky Waves - Longitudinal Waves - Sound Waves

Slinky Waves - Transverse Waves - Water Waves

I Used to Think... But Now I Know...

What is energy?

The ab ilit y to do w ork or cause change.

Work is t h e a p p lica t ion o f a fo rce t h rou g h a d ist a n ce . (Ask th e stu d e n t s fo r e xa m p le s, su ch a s m ovin g a b ox a c ross t h e room , sw e e p in g , e t c .)

- Force ca n p u t m a t t e r in to m ot ion o r stop it if it is a lre a d y m ovin g .

- Mot ion is a ch a n g e in p osit ion o f a n ob je c t w ith t im e .

To d o w ork, e n e rg y is n e e d e d .

From where does energy come?

Na tu ra l e n e rg y sou rce s: food , w a te r, p la n t s, t re e s, g ra vity, su n , fo ssil fu e ls, u ra n iu m , p lu ton iu m

Wa ys th a t h u m a n s h a ve h a rn e sse d o r con ve rt e d n a tu ra l e n e rg y sou rce s: h yd roe le c t ric d a m s, coa l/o il p ow e r p la n t s, n u c le a r p ow e r p la n t s, w in d tu rb in e s, so la r p a n e ls, e t c .

What are different types of energy? (Se e t h e Voca b u la ry / De fin it ion s se c t ion .)

Kin e t ic e n e rg y: e le c t rica l, lig h t , t h e rm a l, so la r, sou n d , w in d , h yd ro

Po te n t ia l e n e rg y: ch e m ica l, m e ch a n ica l, n u c le a r, g ra vit a t ion a l

How do we use energy?

To b re a k d ow n a n d d ig e st food (in ou r b od ie s)

To h e a t h ou se s a n d o th e r b u ild in g s

To illu m in a t e lig h t s