Unit B.2 Science 10

Question 1

Why was energy a difficult concept to define?

Answer 1

Because we only see evidence of energy when it does something

Question 2

How did early scientists get an idea of what energy was?

Answer 2

The development of the concept of energy went hand in hand with the development of technologies that use energy

It was thru observing changes in these technologies that scientists started to get a clear idea of what energy was

Question 3

What is chemical energy?

Answer 3

Chemical energy is the energy stored in the chemical bonds of compounds

Question 4

What did Antoine Lavoisier realize?

Answer 4

That when equal amounts of different substances burned, they produced different amounts of heat

Question 5

Give an example of how chemical energy can be converted to heat.

Answer 5

When wood burns, the energy in the cellulose molecules is released & turned into heat

Question 6

What is electrical/electric energy?

Answer 6

Electric energy is a form of kinetic energy produced by moving charges

Question 7

Who are the 5 major scientists that helped discover & invent stuff on electrical energy?

Answer 7

1. Alessandro Volta
2. Hans Oersted
3. Michael Faraday
4. Thomas Seebeck
5. Thomas Edison

Question 8

From Topic 2.1, what are the 5 major discoveries of the “electrical” scientists?

Answer 8

1. Battery, chemical energy can be converted to electrical
2. Electrical energy can produce magnetism
3. Magnetism can produce electricity
4. Difference in heat can generate electricity/ heat can be converted into electricity
5. Electrical energy can produce light and heat energy

Question 9

From Topic 2.1, what are the 5 major inventions of the “electrical” scientists and how did they figure it out?

Answer 9

1. 1st ever battery, 2 types of metal (copper & silver) with moistened paper sandwiched in between
2. electromagnet; accidently moved a wire with a current over a compass needle and it moved
3. Electric generator; moved a magnet in & out of a coil of wire it produced a current
4. thermocouple; made a loop out of 2 metals; heated one of the junctions and the entire loop got a current going
5. lightbulb

Question 10

What is nuclear energy?

Answer 10

Nuclear energy is the potential energy stored in the nucleus of an atom

Question 11

What is the difference between nuclear fusion & fission?

Answer 11

Nuclear fusion = Joining of 2 nuclei

Nuclear fission = Splitting of a nucleus

Question 12

Who led the way to the development of nuclear energy and what exactly did he observe?

Answer 12

Henri Becquerel, and he observed that atoms spontaneously disintegrate and in the process emit radiation/ radiant energy

Question 13

What did scientists originally think fueled the sun?

Answer 13

Chemical energy but then they realized all the sun’s mass would’ve been burned/used up 5000 years ago

Question 14

What is solar energy? and how do we “experience it”

Answer 14

Solar energy is the H-H nuclear fusion that happens in the sun. This releases nuclear energy which travels to the earth as electromagnetic radiation and is converted to other forms of energy such as heat

Question 15

Who reasoned newton’s cradle and what did he reason?

Answer 15

Gottfried Leibniz reasoned that whatever caused the ball to move resembled a force that’s being transmitted through the balls

Question 16

What did Gottfried Leibniz name energy before James Prescott joule properly named it?

Answer 16

Leibniz named it “vis viva”

Question 17

What are the 2 types of “vis viva” that Leibniz said could be observed in nature?

Answer 17

1. Flowing water, wind or any object in motion could be made to do work and thus has kinetic energy
2. An object raised above earth’s surface has the potential to do work because of it’s position and thus has gravitational potential energy

Question 18

Who is joseph black and what did he experiment, observe and state?

Answer 18

Joseph black stated that heat was a fluid called “caloric fluid” that flows naturally from a hot substance to a cold one

He did this by placing a cold object in hot water and then realizing the object became warm.

Question 19

What did other scientists observe about heat?

Answer 19

Other scientists suggested that the movement of atoms within a substance determines the thermal energy of the substance.

Atoms move or vibrate more quickly in hot than cold substances. The transfer of this thermal energy from a hot object to a cold object is defined as heat.

Question 20

Who were the 4 major scientists in heat energy and what did they do?

Answer 20

Count Rumford:

• proved joseph black’s caloric fluid theory wrong
• 1st to realize heat and mechanical energy are related
• Realized by observing canons being hollowed out and seeing how it has endless heat coming off of it

Thomas young:

• Young proved that mechanical energy had kinetic and potential energy
• He also thought that mechanical energy was related to the work a system can do.

Sadi Carnot:
- Carnot discovered that the transformation of heat into mechanical energy could only occur when thermal energy flows from a hot object to a cool object.

James Prescott Joule:
- properly substituted the term “energy” for vis viva. He argued that heat is just another form of energy

Question 21

What are joule’s 2 experiments and what did they prove?

Answer 21

Joule’s 1st experiment is 2 masses falling and the energy transferring to kinetic energy and finally heat

Joules 2nd experiment: A wood block with Ep is falling and strikes the 2nd wood block which gains transferred kinetic energy from the 1st wood block

Question 22

What is potential energy?

Answer 22

Energy that is stored/held

Question 23

What does the type of potential energy depend on?

Answer 23

Depends on how the energy is stored, whether through position or elasticity or chemicals waiting to react etc.

Question 24

Mass & Weight; which is the scalar quantity and which is the vector and why?

Answer 24

Mass is a scalar quantity: M and is measured in kg:
It’s a measure of the amount of matter that makes it up

Weight is a vector quantity & force: The weight of an object is the gravitational force exerted on it by a large body

Question 25

What is the formula for weight?

Answer 25

Fw = mg; W→: N = kg(m²/s²)

Question 26

What is the unit for gravity and it’s definition?

Answer 26

Gravity is acceleration due to a large body so m/s²

Question 27

What has chemical potential energy?

Answer 27

Any substance that can be made to do work through a chemical reaction

Question 28

What 2 factors does the kinetic energy of an object directly vary with and how?

Answer 28

Mass and speed

Double the mass = Double the kinetic energy
Double the speed = (2)² the kinetic energy

Question 29

What does the conservation of mechanical energy state?

Answer 29

States that the total amount of energy in a given situation remains constant; Energy can be converted from one form to another but it can never create or destroy energy

“Within an isolated system, energy can change form (between potential and kinetic), but the total amount of mechanical energy remains constant.”

Question 30

What does mechanical energy mean?

Answer 30

Energy due to motion & position because when energy is transferred to an object, it causes a change in both potential and kinetic energy at the same time