Energy types notes 2010

Wt=50N

1. What is the KE at point A? Why?2. What is the PE at point A?3. What is the ME at point A?4. What is the height at point B?5. What is the height at point C?

A.

B.C.

WARM UP

Warm up…

1. What is heat?

2.How does thermal energy play a role in the Law of Conservation of Energy?

Bill Nye; HeatBEFORE: List the forms of energy that

you know and understand

DURING: Write notes about heat, conduction, convection, radiation

AFTER: Write a paragraph that describes thermal energy, heat, and the processes of conduction, convection, and radiation.

Roller Coaster Energy Problems

1. Find the PE at point A.2. Find the KE at point A.3. Find the ME at point A.4. Find the KE at point B.5. What is the ME at point C?6. Find the PE at point C.7. Find the KE at point C.

HT=250 mWT=200N

HT=20 mWT=200NM=20kg

V=200m/s

Answer the problems on the left on your sheet under the

roller coaster picture.

A.

B.C.

Warm up…

1. Describe the energy transfers that occur in a light bulb.

2. Describe the energy transfers that occur when the body is

powered by food.

Warm up…

1.Describe the energy transfers in a hairdryer.

2.What is the difference between renewable and

nonrenewable energy resources?

Types of EnergyForms Explanation Example

MechanicalTotal energy of

motion and position

ThermalTotal kinetic energy

of particles

ChemicalEnergy stored in

rearranging atoms

Types of EnergyElectrical

Energy of moving electrons

SoundEnergy of vibrating

particles

LightVibrations of electrically

charged particles

NuclearEnergy in the nucleus of

an atom

1. Mechanical Energytotal energy of motion and position

ME=KE + PE

An object on the top of a hill has high ____ energy and low ____ energy.

As the object rolls down, what happens?

Why does there seem to be less energy at the bottom of the hill than at the top?

2. Electrical Energythe energy of moving electrons

Like charges repel and

Opposite charges attract

++

+ -

Two Types of ElectricityStatic Electricity

Current Electricity

The Power of ElectricityCan be turned into other kinds of energyCan do work

Hairdryer converts electric to thermalAlarm clock converts electric to sound and

light

3. Nuclear Energy

Fission Fusion

the energy of the nucleus of an atom

Pros and Cons of Nuclear Energy

+ make electrical energy

+ no carbon dioxide or other gases

- limited fuel supply - radioactive waste

products- possible release of

radioactive material

+ fuel is plentiful+ only small amounts

of radioactive waste products

- not currently

practical - large amount of

energy needed to heat and contain the hydrogen plasma

Fission Fusion

The Sun

Giant nuclear fusion reactor

Ultimate source of energy for our planet

4. Chemical Energythe energy of rearranging atoms

Is photosynthesis endothermic or exothermic?

Is respiration endothermic or exothermic?

5. Sound Energy

-caused by vibrations & carried through a substance.

the energy of vibrating particles

Making Sound vs. Hearing Sound

Have you heard this riddle?

If a tree falls in the forest and no one is around to hear it, does the tree make a sound?

What do you think?

0

When a tree falls and hits the ground, the tree and the ground vibrate. These vibrations are

transferred to the surrounding air.

So there would be a sound!!!

0

Change Frequency = Change Pitch

TRY IT! – Vocal cordsWATCH IT! – Jars vs. Bottles

TRY IT!Hold the cut rubber band stretched tight.

Have a partner pluck the rubber band with their finger.

Notice the pitch.

Shorten the length of rubber band by holding it in the middle.

What was different??

Echolocation

6. Light Energythe vibrations of electrically charged particles

Called PHOTONS

The EM SpectrumVisible light is one portion of

the Electromagnetic Spectrum.

All of these waves are energy-filled waves.

Insects, like bees, see shorter wavelengths than humans. What type of EM waves do they see?

WATCH IT! - prism

Possibilities of LightLight rays move away from their source in straight lines.

When they hit something, they are either

Reflected(bounced off)

Refracted(bent)

Absorbed(stopped)

WATCH IT! - Mirror

TRY IT!Fill beaker half full of water. Put a pencil in the glass.Look at the pencil through the side of the

glass.How does the pencil look different than it did

before you put it in the water?This is an example of ______________.

TRY IT!Prop up the card with the arrow on it.

Place a glass of water a little to one side of the card and a few inches in front of it.

Now stoop down until your eyes are level with arrow.

Slide the glass between the card and your eyes. Try sliding it back and forth a few times.

What happened? What causes this?

Light Source or Not?You can see a light source even in the dark because its light passes directly into your eyes. Most things around you are not light sources. Why can you still see them?

You can still see them because light from light sources reflects off the objects and then travels to your eyes.

The Speed of LightWatch this clip to learn more about the speed of

light.

Check your Light Understanding

What is a photon?

On the EM spectrum, what type of EM radiation has the highest energy – radio waves, gamma rays, or x-rays?

What are 3 possible things that can happen to light rays after they leave the source?

Sound & Light: Alike, but Different

Sound*vibration*needs a medium

*longitudinal

Light

*does NOT need a

medium*transverse

Both

are

WAVES

7. Thermal Energy

more thermal energy = faster moving particles

less thermal energy = slower moving particles

the total kinetic energy of the particles

Thermal Energy vs. HeatHeat is the transfer of energy between objects that are at different temperatures.

Three Kinds of HeatConduction Convection

Radiation

(touch) (current) (rays)

Hot Cold

Common

Check your Thermal UnderstandingIs thermal energy kinetic or potential?

If you touch something in which the particles are moving faster than the particles in your skin, how would it feel?

When objects have more thermal energy than their surroundings, what do you predict will happen in terms of heat?