energy. what is energy? energy is the capacity to do work or to produce heat

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ENERGY

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Page 1: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

ENERGY

Page 2: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

What is energy?

Energy is the capacity to do work

or to produce heat.

Page 3: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Forms of Energy

Energy comes in many forms, but they can beconveniently classified into three categories.

Radiant Energy

Kinetic Energy

Potential Energy

Page 4: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

What is radiant energy?

Radiant energy is energy given off by thesun that can travel through empty space.

Page 5: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Examples of Radiant Energy

Visible light

X-rays

Radio waves

Page 6: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

What is kinetic energy (KE)?

Kinetic energy is energy in motion.

Page 7: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Types of kinetic energy

Mechanical energyEXAMPLE: a moving car

Thermal (or heat) energyEXAMPLE: boiling a pot of water

Page 8: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

What is potential energy (PE)?

Potential energy is stored energy.

Page 9: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Types of potential energy

Gravitational potential energyEXAMPLE:

Electrical energyEXAMPLE:

Page 10: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Types of potential energy

Chemical energyEXAMPLE:

Page 11: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Law of Conservation of Energy

The law of conservation of energy states that energy is

neither created nor destroyed. It can betransformed from one kind of energy into

another.

Page 12: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Energy Transformation

Modern civilization is possiblebecause we have learned how tochange energy from one form toanother and use it to do work forus and to live more comfortably.

Page 13: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

SOURCES OF ENERGY

Page 14: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Measuring Energy

Energy can be measured using:a.) Calorie (C) the energy stored in food

b.) calorie (cal) the amount of heat needed to raise the temperature of 1g of water x 1°C

c.) Joule (J) SI unit of energy (1 cal = 4.184 J)

Page 15: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Practice Problems

Conversion between calories and joules ( 1 cal = 4.184 J)

1.If a container of water absorbs 25 calories of energy, how many joules of energy did the water absorb? (cal J)

(1 cal = 4.184 J)

Page 16: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

2.If a container of water absorbs 400 joules of energy, how many calories of heat did the water absorb? (J cal)

(1 cal = 4.184 J)

Page 17: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

3.Suppose you use 135 cal of energy to perform a task. How many joules have you used? (cal J)

(1 cal = 4.184 J)

Page 18: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Practice Problems

c. 20 kilocalories joules

20,000 cal

d. 2.4 kilojoules calories

2,400 J

Page 19: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

DO NOW: Energy Concept Map

ENERGY

Page 20: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

Energy Transformations

Burning gas to drive a car

chemical thermal mechanical

Page 21: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

2.1 Review and ReinforcementCalorie and Joule Conversions

14. Convert 5.42 calories and joules. (1 cal = 4.184 J)

Page 22: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

15. Convert 726.030 calories to kilojoules. (1 cal = 4.184 J)

Page 23: ENERGY. What is energy? Energy is the capacity to do work or to produce heat

16. Convert 60.5 J to calories. (1 cal = 4.184 J)