The original portfolio wants you to design a device that either minimizes or maximizes energy transfer, construct the device and test the device. You will need to submit the following:

Question

1 - Concept Map (located on page 16 of Lesson 6)

2 - Written design plan for creating your thermal device

3 - Draw and Write document (located on page 9 of Lesson 8) either digitally or print it and scan it/upload it to the drop box. You will….

Draw a model for the thermal energy device you design.
Explain in the model how thermal energy is being transferred (including on the molecular level)
Label your model
Write in complete sentences how your device transfers thermal energy and the impact it has on the physical properties of the substance you are using in the “Write” portion of the paper.
This can be a fun assignment where you can design a solar cooker to make S'mores or even design an insulated bottle. Be creative in what you design, and try to use materials that you can find around the house.

Answer 1

1 - Concept Map

Title: Energy Transfer Device Concept Map

Main Idea: Designing a Thermal Energy Device

Subtopics:

• Purpose:

  • Minimize Energy Transfer
  • Maximize Energy Transfer

• Examples:

  • Solar Cooker
  • Insulated Bottle
  • Heat Exchanger

• Materials Required:

  • Cardboard
  • Aluminum Foil
  • Insulating Materials (e.g., Styrofoam, fabric)
  • Glass Container
  • Thermometers

• Mechanisms of Energy Transfer:

  • Conduction
  • Convection
  • Radiation

• Testing:

  • Measure temperature changes
  • Time taken for cooking or heating

2 - Written Design Plan for Creating a Thermal Device

Title: Design Plan for a Solar Cooker

Objective: To create a solar cooker that utilizes sunlight to cook food, thereby maximizing thermal energy transfer from the sun to the food.

Materials Needed:

• Cardboard box (medium-sized)
• Aluminum foil (to reflect sunlight)
• Plastic wrap (to cover and create a greenhouse effect)
• Black paper (to absorb heat)
• Cooking container (like a small dish)
• Thermometer
• Scissors
• Tape

Steps for Construction:

1. Prepare the Box: Take the cardboard box and cut a flaps at an angle to create a reflective surface facing the sun. The size of the flap should be appropriate to direct sunlight into the cooker.

2. Apply Reflective Material: Cover the inside of the flap with aluminum foil, shiny side out, to reflect sunlight into the box.

3. Paint the Bottom: Line the bottom of the box with black paper to absorb maximum heat. The black surface will convert solar energy into thermal energy effectively.

4. Seal the Box: Place the cooking container inside the box and cover the top with plastic wrap, ensuring it is tightly sealed. This creates a greenhouse effect and retains heat within.

5. Positioning: Place the solar cooker outside in direct sunlight, positioning it towards the sun to maximize exposure.

6. Testing: Use a thermometer to measure the internal temperature of the solar cooker at regular intervals, noting the time it takes for the food to cook.

3 - Draw and Write Document

Model Drawing: (If this were a visual document, include a hand-drawn or digital sketch of the solar cooker. Label components such as "Aluminum Foil Reflector," "Black Paper Heat Absorber," and "Plastic Wrap Cover.")

Explanation of Energy Transfer: The solar cooker operates on the principle of energy transfer through radiation, conduction, and convection.

• Radiation: Solar energy is transferred from the sun to the aluminum foil, where it reflects and directs the energy into the interior of the cooker.

• Conduction: The black paper absorbs the solar radiation and increases in temperature, thereby conducting heat to the cooking container placed on it.

• Convection: The air inside the cooker heats up, and this warm air causes the temperatures to rise within the enclosed space, cooking the food efficiently.

On a molecular level, as the black paper absorbs thermal energy, its molecules begin to vibrate and move faster, increasing the temperature of the cooking container and subsequently the food. This transfer of energy alters the food’s physical properties, effectively cooking it by breaking down molecules in a process known as thermal conduction.

Impact on Physical Properties: As the thermal energy increases, the structural integrity of the food changes, causing it to soften, change color, and develop flavors. For example, marshmallows and chocolate can melt and combine between graham crackers, creating S'mores, which is the final desired result of this energy transfer process.

By following this design plan and explanation, the solar cooker effectively maximizes energy transfer by harnessing sunlight to achieve cooking through a clever and sustainable approach.