COOKING STOVE FOR KENYA EDSGN 100 TEAM 2

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# COOKING STOVE FOR KENYA EDSGN 100 TEAM 2 - PowerPoint PPT Presentation

COOKING STOVE FOR KENYA EDSGN 100 TEAM 2. Ethan Cook Meshal Alenezi Faris Al Lawati. Table of Contents/Overview. Recognition of Need Problem Description Goals Kenya background Current Stoves used Stakeholders Needs Brainstorm Solution. Recognition of the Need.

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## COOKING STOVE FOR KENYA EDSGN 100 TEAM 2

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Presentation Transcript

GPS:

SP3. Students will evaluate the forms and transformations of energy.

• Analyze, evaluate, and apply the principle of conservation of energy and measure the components of work-energy theorem by
• describing total energy in a closed system.
• relating transformations of potential energy to kinetic energy.
• Analyze the relationship between temperature, internal energy, and work done in a physical system.

ESSENTIAL QUESTION?

Why does society spend a lot of resources on controlling thermal energy?

Temperature and the Phases of Matter
• In the Fahrenheit scale, water freezes at 32 degrees and boils at 212 degrees
• The Celsius scale divides the difference between the freezing and boiling points of water into 100 degrees (instead of 180).
Converting temperatures
• A friend in Paris sends you a recipe for a cake.
• The French recipe says to bake the cake at a temperature of 200°C for 45 minutes.
• At what temperature should you set your oven, which reads temperature in Fahrenheit?
Temperature and the Phases of Matter
• Temperature measures the kinetic energy per atom due to random motion.

SUBLIMATION

EVAPORATION

MELTING

GAS

SOLID

LIQUID

FREEZING

CONDENSATION

DEPOSITION

3 PHASES OF MATTER

Phase changes
• When thermal energy is added or subtracted from a material, either the temperature changes, or the phase changes, but usually not both at the same time.
Key Question:

What is the relationship between heat, temperature, and energy?

Heat and Thermal Energy
Heat and Thermal Energy
• Temperature is NOT the same as thermal energy.
• Thermal energy is energy stored in materials because of differences in temperature.
• The thermal energy of an object is the total amount of random kinetic energy for all the atoms in the object.
• Remember, temperature measures the random kinetic energy of each atom.
Heat and Thermal Energy
• Imagine heating a cup of coffee to a temperature of 100°C.
• Next think about heating up 1,000 cups of coffee to 100°C.
• The final temperature is the same in both cases but the amount of energy needed is very different.
Heat and Thermal Energy
• Heat is what we call thermal energy that is moving.
• The joule (J) is the unit of heat (or thermal energy) used for physics and engineering.
• The calorie is a unit of heat often used in chemistry.

Heat flows from the hot coffee to the cooler air in the room.

Specific Heat
• The specific heat is the quantity of heat it takes to raise the temperature of one kilogram of material by one degree Celsius.
Specific Heat
• The temperature of gold rises quickly compared with water because its specific heat is much less than the specific heat of water.
Heat Equation

Specific heat (J/kgoC)

Heat energy (J)

E = mcp(T2-T1)

Change in

Temperature

(oC)

Mass (kg)

Calculate Heat
• One kilogram of water is heated in a microwave oven that delivers 500 watts of heat to the water.
• One watt is a flow of energy of one joule per second.
• If the water starts at 10°C, how much time does it take to heat up to 100°C?
First Law of Thermodynamics
• Energy loss is equal to energy gain.