Embedded Files
Unit Learning Goals
Unit Learning Goals
To describe energy transfer using the "universe view" of energy
To track energy transfer through the use of energy graphs
To determine the impact of material parameters on energy transfer (Q-calculations)
To relate food calories to energy content
The Universe View of Energy
The Universe View of Energy
Most of us think of energy in terms of how it's useful to us. That's a minimalist view of the true scope of energy. In order to fully understand energy, it requires a "universe view". Scientists are still determining exactly how this universe view works.
The following article explains current research on the theory of "dark energy".
https://www.energy.gov/science/articles/our-expanding-universe-delving-dark-energy
The current theory for the end of the universe is called the Big Freeze. This is the point at which all matter is spread so far apart by dark energy that gravity can no longer affect it.
Things To Know About the Universe View of Energy:
All energy and matter started with the Big Bang approximately 14 billion years ago. The universe has been expanding ever since.
There is a finite amount of energy and matter in the universe.
Energy and matter are constantly being reorganized. Humans view this reorganization as moving from "useful" to "useless", especially for energy.
Scientists originally thought the universe would eventually stop expanding. On the contrary, the universe is currently accelerating outward from the point of the Big Bang.
The current explanation for the acceleration in the universe is "dark energy" - a form of energy that exists in the "empty regions' of space. The repulsive force of dark energy is the opposite of the attractive force of gravity. The acceleration point of the universe is the point at which dark energy repulsion became greater than gravitational attraction.
The following sheets are the reference sheet and class notes for the unit. These sheets are to be used with the portion of the unit involving ENERGY TRANSFER with NO NEW SUBSTANCES BEING PRODUCED.
The following sheets are the reference sheet and class notes for the unit. These sheets are to be used with the portion of the unit involving ENERGY TRANSFER with NO NEW SUBSTANCES BEING PRODUCED.
Energy Ref Page.pdfRef Page Answer #1.pdfRef Page Answer #2.pdfTwo-Substance Energy Transfer Initial Lab
Two-Substance Energy Transfer Initial Lab
The initial lab for this unit involves exploring heat energy transfer between two substances - steel and water. The steel is heated in a burner flame for three minutes before being placed in room temperature water. The change in temperature of the water gives an indication as to the initial temperature of the steel.
Q = (m)(Cp)(Tf-Ti)
Q = (m)(Cp)(Tf-Ti)
Q = heat energy transferred (J)
m = mass (g)
Cp = specific heat of material (J/g*C)
Tf = final temperature (C)
Ti = initial temperature (C)
Energy Graphs - Bar Graphs
Energy Graphs - Bar Graphs
Energy bar graphs are a method of keeping track of energy transfer to ensure conservation of energy. In Chemistry 11, our energy bar graphs include the following categories:
Eth - energy stored as particle movement or speed, indirectly measured by temperature
Ei or Eph - energy stored as particle structure or phase, determined by the state of the material
Ech - chemical change energy determined by enthalpy and entropy calculations in Chemistry 12
Energy Graphs - Heating Curves
Energy Graph and Calculation Practice Problems - the following in-class examples and practice problems cover:
Single Substance Energy Transfer (LOL - Eth only)
Two Substance Energy Transfer (LOL - Eth only, ignore Eph changes)
Heating Curve of Water Transfer (LOL and Heating Curve - Eth and Eph)
This is the point in the unit at which 80% Quiz #1 occurs. This quiz covers:
This is the point in the unit at which 80% Quiz #1 occurs. This quiz covers:
- The Universe View of Energy
- Energy Bar Graphs
- The Heating Curve for Water
- One and Two-substance Energy Calculations
- Phase Change Calculations
ENERGY TRANSFER with NEW SUBSTANCES BEING PRODUCED requires a different set of calculations. These calculations include:
ENERGY TRANSFER with NEW SUBSTANCES BEING PRODUCED requires a different set of calculations. These calculations include:
- Enthalpy
- Entropy
- Gibbs Free Energy
Energy Transfer In Camp Stoves Full Lab
Energy Transfer In Camp Stoves Full Lab
The camping and backpacking communities often use small alcohol stoves as a heat source for cooking food, especially on extended backcountry trips. These stoves are compact, lightweight and must be exceptionally efficient at combusting the alcohol fuel and transferring energy to the meal being cooked.
In order to save money, backpackers and campers often make these camp stoves from recycled materials. This lab will allow you to create a small camp stove, and then test the stove to determine its effectiveness at heating water (this is a prerequisite for many backpacking meals).
The lab procedures are based on the following sources:
https://backpackinglight.com/stovebench/ (This site provides an in-depth description of the testing protocol used to rank the stoves created in class.)
http://zenstoves.net/ (This site has one of the most comprehensive lists of stove plans on the Internet. Although a simple Google search for "DIY alcohol backpacking stoves" will generate a list of sources, most are not as extensive as Zen Stoves.
Stove Building and Testing Guidelines
Stove and Pot Stand Design - Stove and pot stand designs are chosen from ZenStoves.net or another online source. The design must hold a beaker with 500mL of water (2 cups is typical for cooking a backpacking meal). The stove must hold 15mL of alcohol fuel.
Initial Testing - Initial testing is completed and submitted to the class data.
Improvement - Some form of improvement is made to the stove and/or pot stand design.
Final Testing - Final testing is completed and submitted to the class data.
The final lab grade as shown in JMC will include the following:
A completed stove and pot stand with initial and final testing. Initial and final testing data must be submitted to the class data sheet.
A class data sheet filled out with data and photos submitted on Schoology.
A hand-written lab summary based on questions from the lab. This summary will be completed in class.
Skeptical Questions In Science
Skeptical Questions In Science
The skeptical question topic for this unit involves the topic of "the accuracy of fitness trackers in measuring calories burned" . Skeptical questions are thoughtful "Why-based" questions which address biases in scientific material. This type of question is not seeking scientific facts.
The articles associated with this unit are listed below and to the left. Be sure to read ALL THREE ARTICLES!
Resources
Why Some Chemicals Are Combustible (https://www.cas.org/resources/blog/weak-bonds-combustible-chemicals)
NavApp Explosion Calculations (https://www.usna.edu/ChemDept/_files/documents/111pdf/AY_20_21_Documents/SC111_NavApp-_Explosives_adapted_f20_updated_.pdf)
Chemistry of Explosions (https://www.chem.fsu.edu/chemlab/chm1020c/Lecture%207/04.php#:~:text=TNT%20is%20composed%20of%20the,explosives%20contain%20these%20same%20elements)
Slow Mo Guys Explosion Videos on YouTube
Learning To Learn (L2L)" and Retrieval Assignment List (REQUIRED BEFORE UNIT GRADED TEST) and Calibration Test
Learning To Learn (L2L)" and Retrieval Assignment List (REQUIRED BEFORE UNIT GRADED TEST) and Calibration Test
Learning to Learn and Retrieval List
Intro Lab and Reflection (Two-Substance Heat Transfer)
Practice (Energy Transfer Calculations - 2 stapled sheets, Energy in Explosions Video Search)
80% Quiz #1
80% Quiz #2
Quiz Reflections
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