New Core Curriculum:Foundations of Scientific Process

Energy: a Prerequisite for Life

gamma rays

X-rays

Ultra-violetVisible

Infrared

Microwave

Radio waves

• Many wavelengths of light outside of visible

• Astronomers must consider the full EM spectrum

10 m-15

1000 km

EM radiation

What does the Emitted Wavelength of EM Radiation Depend on?

• Temperature of the emitting object

So What Makes Life on Earth Possible?

• The Sun Emits Visible EM Energy Which Provides Global Climate On Earth That Is Conducive To The Formation And Sustenance Of Life As We Know It

Stars are massive gaseous body in outer space that generate energy through nuclear fusion and therefore emit visible light;

Solar energy comes from the rearrangement of protons and neutrons this energy powers the stars

petawatt (1015 watts)

petawatt (1015 watts)

petawatt (1015 watts)

Energy input = Earth’s output

1) Ein (from the Sun) Eout 2) Reflectivity (Albedo)3) Earth’s surface & Atmosphere (Greenhouse gases)

Brightness (Ein) depends on the distance of emitting object:

Ein =

Inverse Square Law:

Measuring ‘b’ and knowing ‘L’ yields ‘d’

What other forms of energy exist besides EM radiation ?

What is Energy?

Energy is defined as the ability to do work and produce/transfer heat

New Core Curriculum:Foundations of Scientific Process

EM radiation is not the only form of energy that exists and that is important for modern life!

ENERGY = WORK +

HEAT

Don’t Confuse Power, Work & Energy…

Energy:• In colloquial

language, ENERGY is equated with vigor, liveliness and vitality

• In science, ENERGY is defined as the ability to do work and transfer heat

WORK not concerned with a nature of the task, tiredness, etc. defined as force acting through certain distance

units: Joules, calories (cal), nutritional Calorie (kcal)

Don’t Confuse Power, Work & Energy…

HEAT energy of atomic / molecular motion this energy always flows from warmer to cooler object

units: Joules, calories (cal), nutritional Calorie (kcal)

Don’t Confuse Power, Work & Energy…

POWERP = W / t

work being done in a certain time frame

units: [J/s = Watts, horse power: 1 hp = 746 W]

Don’t Confuse Power, Work & Energy…

Energy Can Be Classified As Kinetic (KE) or Potential (PE) Energy

PE can be converted to KE and KE can be converted to PE

Etotal = KE + PE

Most technological devices are energy-form converters

out there, here’s the skinny

                                                                                                             

Energy is never created or destroyed, it just converts from one form to another, the total energy always remains constant

Law of Conservation of Energy

Every time work is being accomplished or heating is taking place, energy transfer is taking place

Energy is never created or destroyed

Mechanical energy

Chemical energy

Radiant energy

Electrical energy

Nuclear energy

Various Forms of Energies

Various Forms of Energies

Mechanical energy created by a physical movement, it is characteristic of machines in motion;

Chemical energy energy involving chemical processes (typically oxidation); plants create and store chemical energy from radiant solar energy ;

Electrical energy generated by the flow of electrical charges along a conducting material;

Nuclear energy form of energy originating from collisions of atomic nuclei.

ENERGY RADIATEDBrightness Ğ energy we receive at Earth Ğ

gets less the farther away the star

(1 J/s = 1 Watt)

Radiant energy EM blackbody radiation emitted by all “visible” objects in the universe;

Activity: Chemical Energy & Energy Balance in the Human Body

Activity: Chemical Energy & Energy Balance in the Human Body

Food Serving Size kJ kcal

Skim Milk 8 oz (250 g) 347 83

Whole Milk 8 oz (250 g) 610 146

Mixed Vegetables ½ cup (125 g) 247 59

Broccoli ½ cup (125 g) 63 15

Yellow Corn 1 ear 447 107

Fruit Cocktail ½ cup (125 g) 230 55

Whole Wheat Bread 1 slice 272 65

Baked Potato 1 item 920 220

Black Beans ½ cup (125 g) 477 114

Lean Ground Beef 3 oz (84 g) 966 231

Ground Turkey 3 oz (84 g) 836 200

Butter 1 tbsp (15 g) 451 108

Olive Oil 1 tbsp (15 g) 497 119

Canola Oil 1 tbsp (15 g) 502 120

Sugar 1 tsp (5g) 63 15

Beer 12 oz (375 g) 493 118

Whiskey 1.4 oz (44 g) 432 132

Energy Input

Energy values of foods can be estimated based on the content of:

• Carbohydrate: 17kJ (4.0 kcal) of energy /g

• Protein: 17kJ (4.0 kcal) of energy /g

• Fat: 38kJ (9.0 kcal) of energy /g

• Alcohol: 29kJ (7.0 kcal) of energy /g

Activity: Chemical Energy & Energy Balance in the Human Body

Metabolic Energy: Energy needed to maintain life. Based on sex, weight, and age.For a young adult female, the metabolic rate is ~100kJ per day/kg body weight.

For a young adult male of the same weight and age, the figure is about 15% higher

Activity: Chemical Energy & Energy Balance in the Human Body

Muscular Activity: Energy consumed when muscles contract (writing, walking, playing tennis, or even sitting in class). It is typically anywhere from 50% to 100% of the metabolic energy depending on lifestyle:Let’s say the aforementioned female never lifts anything heavier than a textbook.

Activity: Chemical Energy & Energy Balance in the Human Body

Metabolic Energy + Muscular Activity = kJ/day (kCal / day)

So that’s the number of calories or kJ / day you need.

Activity: Chemical Energy & Energy Balance in the Human Body

Let’s compare the number of calories or kJ / day you need with the energy used by a lightbulb.

Activity: Chemical Energy & Energy Balance in the Human Body

Metabolic Energy: required will vary depending on environmental conditions.

Activity: Chemical Energy & Energy Balance in the Human Body

There are 7 billion humans on earth.

You now know how many kJ of energy the average human needs per day

What is the total energy required for all humans on earth?

What percent of the energy given by the sun is this?

New Core Curriculum:Foundations of Scientific Process

Key sources of energy used today Future sources of energy

In the United States Today the major sources of Energy are Fossil Fuels, Nuclear & Hydroelectric

Other Renewables2% Hydroelectric

5%

Nuclear8%

Coal23%

Natural Gas23%

Petroleum39%

octane, a hydrocarbon found in petroleum

Fossil Fuels Like Natural Gas, Coal & Petroleum are Chemical Sources of Energy

Only a small percentage of our energy comes from non-chemical sources like hydropower & nuclear

Fossil Fuel Reserves(billion oil equiv)

Country Oil coal gas oil + coal + gas

Total with shale

US 21 1284 34 1339 3839

Russia 60 831 280 1171 1626

China 48 442 13 503 519

Australia 130 418 5 553 553

India 5 489 7 502 502

Saudi Arabia 262 0 40 302 302

Iran 136 0 162 298 298

Canada 179 32 9 220 220

Qatar 15 0 152 167 167

Iraq 115 0 19 134 134

Future Carbon Dioxide Emissions ?

Conservation of Energy & Sources for the Future:

Solar energy radiant energy from the Sun

Geothermal energy energy stored beneath Earth’s Crust

Hydrogen energy hydrogen reacting with oxygen releases clean energy (water is by-product)

According to the US department of Energy, US currently consumes ~ 1.06 · 1018 J of energy per year

Solar Thermal : (100kW to 30mW power supply)Pro: clean.

Con: unstable energy production (sunlight less than 50% of time), low energy efficiency, currently heat is taken up by oil and converted into steam to run turbines, the efficiency is 50%, which could be improved by using new material as heat storage media. Geographic limitation - needs large area to install (only 50% of the total area can be used for solar panels).

Alternative Energy Sources SOLAR TECHNOLOGY

What controls local climate?What makes it variable?

differential regional heating due to Earth’s spherical surface: the same amount of radiation is spread over larger surface in north and south latitudes vs. at the equator.

Atmospheric Circulation

sets up convection currents

Coriolis force: due to rotation of the earth acts at right angles to the direction of motion (deflection to the right in the Northern Hemisphere and to the left in the Southern Hemisphere)

Pro: clean (no CO2), cheap to run (comparable to burning coal taking into account of carbon tax in the future).

Con: expensive to set-up, intermittent productivity, hard to store resulting energy, geographic limitation due to space. If we scale up the current production by 80 times to make up for 1 wedge of carbon reduction (Socolow and Pacala 2006), it will likely interfere with the ecosystem and maybe even the climate system by changing wind pattern.

Alternative Energy Sources SOLAR TECHNOLOGY

Wind power: (modern windmill ~2 mW power supply)

Bio-fuel:

Biofuel is defined as solid, liquid or gas fuel derived from relatively recently dead biological material and is distinguished from fossil fuels, which are derived from long dead biological material. There are two common strategies of producing agrofuels. One is to grow crops high in sugar, and then use yeast fermentation to produce ethyl alcohol (ethanol).

Second is to grow plants that contain high amounts of vegetable oil, such as oil palm, soybean. When these oils are heated, their viscosity is reduced, and they can be burned directly in a diesel engine, or they can be chemically processed to produce fuels such as biodiesel.

Alternative Energy Sources SOLAR TECHNOLOGY

Bio-fuel:

Pro: readily applicable, use unlimited source of solar energy.

Con: With the current technology and specific situation in the US, biofuel remain expensive, harms the ecosystem and still produce CO2. Brazil and India could benefit from extracting ethanol from sugarcane that has much higher sugar content than corn, which is the main biofuel crop in the US.

Alternative Energy Sources SOLAR TECHNOLOGY

Alternative Energy Sources GEOTHERMAL ENERGY

making use of Earth’s internal heat

geyser

Hydrogen economy: (100kW to 30mW power supply)Pro: more efficient than fossil fuel for the same amount of energy output. Coal gasification has incentive due to the large reserve in the US and theoretically it’s cleaner than directly burning coal. Con: hard to generate, hard to carry around, and traditional production methods using fossil fuel still generates CO2 by product. Coal gasification plants could generate hydrogen much cheaper (through bring coal to 1300-1400 °C and react it with oxygen to generate CO, H2 and CO2, or called syngas), given that the CO2 generated can be captured and stored properly. Or the most common technology is steam methane reforming (SMR) which uses reaction between hot steam (1000 °C) and methane to make CO2 and H2. But problems remain as how to store hydrogen in automobiles. 

Alternative Energy Sources HYDROGEN TECHNOLOGY

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Hindenburg disaster, 1937

Alternative Energy Sources HYDROGEN TECHNOLOGY

Energy per gram