Energy Transformations

An intro to energy conversions in living things

Molecular Biology Sumner High School

Created by Mr. Woodbury, Modified by K. Slater

Big Question

What is the relationship between life, matter and energy?

Our two first definitions

Energy: The capacity to do work.Examples: Energy stored in gasoline to make a car go, food to supply energy for motion.

Food: Molecules that contain energy that can be converted into a useable form in organisms.

Where is the energy stored?Within strong covalent bonds.

Glucose: C6H12O6

Two categories of energy

Potential Energy: stored energy and the energy of position

ChemicalNuclearGravitationalStored mechanical

The other form...

Kinetic Energy: the energy of motionMotion… duhRadiant (electromagnetic waves… aka light energy)SoundThermal (heat)Electrical

Quick Check

Which of the following is an example of potential energy?

A)The sound of a teacher’s voice

B)Warmth from a heater

C)Sugar

D)Radio signal from a remote control

Answer: C

What types of PE, KE and energy transformations are in this

pic?

#8. Identify one energy transformation…

My list...

Potential EnergyDiver waiting to jump: gravitationalPeople: chemical Sun: nuclear

Kinetic EnergyDiver: motionPeople: sound & thermalSun: thermal & radiantOcean: motion

Energy ConversionsDiver: gravitational (PE) to motion (KE)People: chemical (PE) into thermal, sound & motion (KEs)Sun: nuclear (PE) into thermal & radiant (KEs)

Next Question

Do these forms of energy always stay in the same form?

No, they can be transformed from one type to another.

Energy transformation = changing one form of energy into other forms as a result of some event or process.

Energy Transformations

Remember: energy cannot be…We don’t really “use” energy, we just alter the form or type

Especially in living systems

A mental inquiry...

What are the energy transformations done by an iPod?

List the transformation and the start and end energy types.

Foundation level: transformations done by the iPod itself (general types of energy: potential & kinetic)

Challenge level: include transformations that happen several steps before/after the iPod (detailed types of energy)

The iPod inquiry

Foundation Level: Electricity stored in battery (kinetic to potential)Battery powers light (potential to kinetic)Battery powers headphones (potential to kinetic)

Any ideas for Challenge Level?

Thermodynamics

These are the laws of energy

First Law of Thermodynamics: “Energy can be transferred and transformed, but it cannot be created or destroyed.”

Also known as the principle of conservation of energy.

Key idea: there is a fixed amount of energy in the universe.

Example: Plants do not produce energy; they transform light energy to chemical energy.

Thermodynamics

Second Law: every energy transfer or transformation increases the entropy (randomness or “chaos”) of the universe.

Things are going from being organized to random.

Key idea: No transformation is 100% efficient.

Energy flows towards making more heat, which is the energy of random molecular motion.

Example: nuclear energy of the sun is converted into radiant AND thermal energy

Harnessing Energy

20%20%Musc

leC

ontr

act

ion

Musc

leC

ontr

act

ion

60%60%

Heat

Heat

40%40%

Use

able

by c

ell

Use

able

by c

ell

100%100%

Tota

l E in

Glu

cose

Tota

l E in

Glu

cose

Summarize...

Plan to take 2-3 minutes to silently summarize all of the information so far into one big idea (20 word max?)

I will quasi-randomly call on you to share so we can hear from a variety of people.

My summary...

Living systems transform energy between various forms by controlling the rearrangement of molecules.

Energy conversions in cell processes...

Photosynthesis in the _____________: (organelle name)

Radiant energy (KE) → chemical energy (PE)

Cellular respiration in the _____________:

(organelle name)

Chemical energy (glucose / PE) → chemical energy (ATP / PE) → motion (KE)

Energy Sources...

Create a list of as many types of energy that you can think of (including those in today’s PPT)

For each type of energy, identify it as potential or kinetic energy