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1. Science 10 > Text B Technological Systems 4.2 Theories Of Heat > Flashcards

Text B Technological Systems 4.2 Theories Of Heat Flashcards

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1
Q

What species is known to have learned to cook with fire before Homo sapiens existed?

A

Homo erectus

Evidence suggests Homo erectus used fire for warmth and cooking.

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2
Q

How long have intelligent beings been using fire according to scientific findings?

A

At least 400,000 years

This predates the existence of Homo sapiens.

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3
Q

What are the four elements according to the theory proposed by Empedocles?

A
  • Earth
  • Air
  • Fire
  • Water

Each element was believed to have specific qualities connecting them.

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4
Q

What qualities are associated with fire in the theory of the four elements?

A

Hot and dry

This theory describes how elements interact based on their qualities.

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5
Q

Who proposed the Phlogiston Theory and when did it become popular?

A

The Phlogiston Theory became popular in the early 1700s

It was based on the idea of an invisible fluid that substances contained.

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6
Q

What is phlogiston believed to do when an object burns?

A

Flow out of the object

The theory suggested that burning released phlogiston, leaving ashes behind.

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7
Q

What was the main issue with the Phlogiston Theory observed in substances like magnesium?

A

Ashes had a larger mass than the original substance

This contradiction led to the decline of the Phlogiston Theory.

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8
Q

What does the Caloric Theory propose about heat?

A

Heat is a massless fluid that flows from warmer to cooler objects

This theory explained many observations about heat at the time.

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9
Q

What happens when ice is placed in water according to the Caloric Theory?

A

Caloric flows from the water into the ice, causing it to melt

This illustrates the transfer of heat between substances.

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10
Q

Who defined the unit of caloric and what is it called?

A

Joseph Black defined the unit called the calorie

1 calorie increases the temperature of 1 gram of water by 1°C.

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11
Q

For how long have scientists understood the nature of heat?

A

Less than 200 years

This highlights the relatively recent development of thermodynamics as a science.

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12
Q

What compound is formed when magnesium burns in the presence of oxygen?

A

Magnesium oxide

The mass of magnesium oxide is greater than the mass of the original magnesium.

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13
Q

What was magnesium used for in old flash bulbs?

A

To produce a bright light when it burned

Magnesium fibers were sealed with oxygen inside the bulbs.

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14
Q

Who was the first person to reveal flaws in the caloric theory?

A

Benjamin Thompson

He was also known as Count Rumford after moving to Bavaria.

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15
Q

What was Benjamin Thompson’s title after moving to Bavaria?

A

Count Rumford

He became the Imperial Count of the Holy Roman Empire.

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16
Q

What observation did Count Rumford make regarding the boring of metal?

A

The tools, metal, and metal shavings became very hot

This was unexpected as none of the objects were hot before the process.

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17
Q

What hypothesis did Count Rumford propose regarding heat?

A

There is no substance such as caloric; mechanical energy is converted into heat

This suggested that heat is equivalent to energy.

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18
Q

In what year did Count Rumford publish his hypothesis about the relationship between mechanical energy and heat?

A

1798

His hypothesis contradicted the widely accepted caloric theory.

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19
Q

Who found evidence supporting the relationship between energy and heat many years after Rumford?

A

Julius Robert Mayer

He discovered this relationship through a different method.

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20
Q

What was Mayer’s profession before discovering the relationship between energy and heat?

A

Ships doctor

He served on a voyage to the East Indies.

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21
Q

True or False: The caloric theory was widely accepted despite Rumford’s hypothesis.

A

True

Rumford’s ideas were ignored for a long time due to the acceptance of the caloric theory.

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22
Q

Fill in the blank: Count Rumford was astonished by the extremely hot metal ______ produced by boring holes in metal cylinders.

A

shavings

This intense heat could not be explained by the caloric theory.

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23
Q

What is bloodletting?

A

A historical medical practice where blood was removed from a patient to treat illness.

Practiced from the days of early Greek physicians until the late 1800s.

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24
Q

What color is blood in an artery and why?

A

Bright red because it is fully oxygenated.

It carries the maximum amount of oxygen.

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25
What color is blood in a vein and why?
Darker red due to having less oxygen. ## Footnote Dark red blood flows back to the heart.
26
How does the color of blood relate to energy and heat?
The body uses oxygen to break down food for energy, and this process generates heat. ## Footnote Mayer reasoned that more heat generation in cooler climates requires more oxygen.
27
Who was Mayer and what was his contribution to understanding blood and energy?
Mayer was one of the first scientists to recognize that the body uses oxygen to break down food for energy. ## Footnote He connected oxygen usage with heat generation.
28
What was Count Rumford known for besides his experiments on heat?
His invention of the Rumford fireplace, which is still in use today. ## Footnote He also had a notable technological problem-solving strategy.
29
What was the belief regarding bloodletting and diseases?
Doctors believed that diseases were caused by an imbalance of fluids in the body. ## Footnote They thought removing blood could correct this imbalance.
30
Fill in the blank: Blood in the tropics may appear _______ due to the high levels of oxygen.
bright red
31
True or False: People in cooler climates use less oxygen than those in tropical climates.
False ## Footnote People in cooler climates generate more heat and therefore use more oxygen.
32
What scientific paper did Mayer write upon returning home to Germany?
A paper about energy and heat ## Footnote Mayer was not formally trained in physics and math, which affected the quality of his presentation.
33
What did Mayer do to improve his scientific work?
He began to study physics and math ## Footnote This was in order to formulate his theory in a more acceptable way.
34
Who is credited with discovering the mechanical equivalent of heat?
James Prescott Joule ## Footnote Joule's work was recognized despite Mayer's correct scientific contributions.
35
What is the SI unit of energy named in honor of Joule?
The joule ## Footnote Joule performed accurate measurements relating mechanical energy to heat.
36
How do physicists define energy?
As the ability to do work ## Footnote This definition encompasses various forms of energy, including kinetic energy.
37
What is the formula for calculating work?
W = F * A * d ## Footnote Where W is work in joules, F is force in newtons, and d is distance in meters.
38
What does 'W' represent in the work formula?
Work in joules ## Footnote It quantifies the energy transferred when a force moves an object.
39
What does the symbol delta (Δ) represent in the formula for work?
Change or difference ## Footnote It indicates the difference between two positions in the context of work.
40
What is the meaning of the term 'calorie'?
A unit of energy measurement ## Footnote The calorie (lower case c) and Calorie (upper case C) have different meanings.
41
What prefix do we use today instead of the upper case C in Calorie?
kilo- ## Footnote This refers to the kilocalorie, which is commonly used in nutritional contexts.
42
What happens when you stretch or compress a spring?
You do work on the spring and transfer energy ## Footnote The spring stores energy and will return to its original length when released.
43
What is the GRASP method used for?
To organize the thinking process when solving problems ## Footnote It helps in systematically approaching model problems in physics.
44
What is kinetic energy?
A form of mechanical energy associated with moving objects ## Footnote It is one of the key concepts in understanding energy in physics.
45
True or False: Mayer's work on energy and heat was immediately recognized.
False ## Footnote His paper was overlooked initially due to poor presentation.
46
What does a graph of force versus position help visualize?
The amount of work done by a force ## Footnote This method provides a different perspective on calculating work.
47
What is the formula for the area of a rectangle?
Area = length × width ## Footnote This formula is fundamental in geometry.
48
In the force versus position graph, what does the long side of the rectangle represent?
The force ## Footnote This is depicted on the vertical axis of the graph.
49
In the force versus position graph, what does the width of the rectangle represent?
The distance over which the force acted ## Footnote This is shown on the horizontal axis.
50
What does FAd represent?
The amount of work done by the force ## Footnote F is force and Ad is distance.
51
What does W represent in the context of work?
Work done by the force ## Footnote W is used to denote work in physics.
52
Calculate the work done if the force is 10 N and the distance is 4.0 m.
W = (10 N)(4.0 m) = 40 J ## Footnote This calculation illustrates how to derive work from force and distance.
53
What is the relationship between area under the curve and work done in a force versus position graph?
The area under the curve equals the amount of work done by the force ## Footnote This is a crucial concept in understanding work in physics.
54
True or False: The area under the force versus position curve is a rectangle if the force is constant.
True ## Footnote A constant force results in a rectangular area on the graph.
55
Fill in the blank: The area under the curve of force versus position is equal to _______.
the amount of work done by the force ## Footnote This highlights the significance of graphing in physics.
56
What apparatus did Joule use to determine the mechanical equivalent of heat?
An apparatus that stirred water using a falling weight to turn a drum ## Footnote Joule's experiment involved measuring the force of gravity, the distance fallen, and the resulting temperature change of water.
57
How does the force of gravity contribute to Joule's experiment?
It causes the weight to fall, which pulls on a string to turn the drum that stirs the water ## Footnote This indirect work done on the water is crucial for measuring energy transfer.
58
What was the relationship Joule established in his experiment?
The amount of work done on the water is related to the change in the temperature of the water ## Footnote Joule's findings were foundational in understanding the conversion of work to heat.
59
What is the amount of work Joule determined caused a 1.0°C increase in temperature for 1.0 g of water?
4.16 J ## Footnote Modern precision instruments measure this value as 4.186 J.
60
What is the definition of a calorie as established by Joseph Black?
The amount of caloric needed to raise the temperature of 1.0 g of water by 1.0°C ## Footnote This definition also applies to energy, with 1 cal being equivalent to 4.186 J.
61
What law did the work of Mayer and Joule lead to?
The law of conservation of energy ## Footnote This law states that energy cannot be created or destroyed, only converted.
62
Fill in the blank: The modern definition of heat is the amount of energy that must be added to 1.0 g of water to increase its temperature by _______.
1.0°C
63
True or False: Joule's measurements had an error of more than one percent.
False ## Footnote Joule's error in measurements was less than one percent.
64
What did Joule's experiment help to quantify?
The mechanical equivalent of heat ## Footnote This was a pivotal development in thermodynamics.
65
What occurs in a substance when it becomes warmer, according to the kinetic-molecular theory?
The individual molecules move faster and vibrate more. ## Footnote This movement is not a flow of heat, but an increase in kinetic energy of the molecules.
66
What is the kinetic-molecular theory of heat?
It states that heat is the transfer of thermal energy, not a fluid that flows into substances. ## Footnote This theory contrasts previous ideas that heat was a substance.
67
How do molecules in a solid behave when the solid becomes warmer?
Molecules vibrate faster while remaining in fixed positions. ## Footnote They can be visualized as being attached by springs.
68
What is the definition of heat in the context of thermal energy?
Heat is defined as the transfer of thermal energy from one object to another. ## Footnote This is different from work, which is the transfer of mechanical energy.
69
What is kinetic energy?
The energy of motion. ## Footnote It is directly related to the temperature of a substance.
70
What happens to water molecules when paddles push them in Joule's experiment?
The water molecules move faster and collide with each other. ## Footnote This illustrates the transfer of energy and the increase in kinetic energy.
71
True or False: Heat is a fluid that flows into a substance to make it warmer.
False. ## Footnote Heat is the transfer of energy, not a physical fluid.
72
What happens to the average speed of water molecules when water is hot?
The average speed of the molecules is high. ## Footnote When water is cool, the average speed is low.
73
Fill in the blank: The current theory of heat is called the _______.
kinetic-molecular theory. ## Footnote This theory developed over time, replacing earlier theories.
74
What historical theories of heat were replaced by the kinetic-molecular theory?
Phlogiston theory and caloric theory. ## Footnote These theories were set aside as scientific understanding improved.
75
What is the relationship between thermal energy and the motion of molecules?
Thermal energy is directly related to the kinetic energy of the molecules. ## Footnote Increased thermal energy results in increased molecular motion.
76
What does the amount of thermal energy in a substance depend on?
The amount of the substance ## Footnote More thermal energy is present in larger quantities of a substance.
77
Does temperature depend on the amount of the substance?
No ## Footnote Temperature is independent of the amount of substance present.
78
Who aimed to determine the 'mechanical equivalent of heat'?
James Joule ## Footnote Joule's experiments significantly contributed to the understanding of heat and energy.
79
What is specific heat capacity?
The amount of energy required to increase the temperature of 1 g of a substance by 1°C ## Footnote Represented by the symbol c.
80
What is the specific heat capacity of water?
c = 4186 J/g*°C ## Footnote This value applies specifically to water.
81
What does temperature measure?
The average kinetic energy of the individual atoms or molecules in a substance ## Footnote Temperature reflects molecular motion.
82
What is the relationship between temperature change and thermal energy?
A temperature change is not a measure of the amount of thermal energy added ## Footnote Different substances require different amounts of energy for the same temperature change.
83
What does thermodynamics study?
Forces and motion involving heat and the transfer of thermal energy ## Footnote The term combines 'thermo' for heat and 'dynamics' for forces and motion.
84
Who formalized the first law of thermodynamics?
Hermann von Helmholtz ## Footnote The first law was derived from the work of Mayer and Joule.
85
Fill in the blank: The field of physics that deals with heat and thermal energy is called _______.
thermodynamics ## Footnote This field emerged from the study of steam engines.
86
True or False: The same values of specific heat capacity apply to all substances.
False ## Footnote Each substance has its unique specific heat capacity.
87
What does the First Law of Thermodynamics state?
Energy cannot be created or destroyed, but can be transformed or transferred. ## Footnote Another way to state the first law is that the total energy of the universe is constant.
88
Who presented on the topic of thermodynamics in 1847?
Joule ## Footnote Joule's presentation stimulated further discussion and inquiry into thermodynamics.
89
What important question did William Thomson raise after Joule's presentation?
He asked questions that led to important discussions about thermodynamics. ## Footnote This discussion helped deepen the understanding of thermodynamic theory.
90
What is the Second Law of Thermodynamics?
It is not possible for any process to convert thermal energy entirely into work. ## Footnote Another way to phrase it is that no process can be 100 percent efficient.
91
What does the Second Law of Thermodynamics indicate about energy efficiency?
Some energy will always remain as thermal energy and cannot be converted to work. ## Footnote This leftover thermal energy is often referred to as 'wasted' heat.
92
How does thermal energy flow according to the Second Law of Thermodynamics?
Thermal energy always flows from a higher temperature object to a lower temperature object. ## Footnote This process occurs spontaneously without energy input.
93
What must be done to make a refrigerator cooler than its surroundings?
Energy must be used to remove heat from the inside of the refrigerator. ## Footnote This is an example of a process that does not occur spontaneously.
94
How did Einstein's theory of relativity expand the First Law of Thermodynamics?
It included mass as a form of energy that can be converted to energy. ## Footnote This expansion is important for understanding energy sources in nuclear reactors and the Sun.
95
At what age did William Thomson enter university?
10 years old ## Footnote His early entry into university highlighted his exceptional intelligence.
96
What title was William Thomson granted for his contributions to science and technology?
Lord Kelvin ## Footnote He was honored with a knighthood by Queen Victoria.
97
What is the Kelvin scale named after?
William Thomson, also known as Lord Kelvin. ## Footnote The Kelvin scale is an absolute temperature scale.

1. Science 10 (44 decks)

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