Name: ______Date: ______Hour: 1 2 3 4 5 6

Focus on Food Lab Activity (Solar Cooker)

Introduction:

You have dealt with parabolas in math before, and now are learning their connections to the real world. Satellite dishes and headlights both work because of the reflection properties of a parabola. When parallel (to the axis of symmetry) rays such as radio waves, coming from far away, strike the sides of a parabola, they are reflected through the focus, thus begin concentrated and picked up by the necessary divide placed at the focus of the satellite dish. When a signal is sent out from the focus, it reflects off the sides of the parabola, moving out in parallel (to the axis of symmetry) beams. In the same way, the light from the bulb in a headlight is sent out directly in front of the car.

We have looked at the definition, details, characteristics, and uses of parabolas in the notes. You will put these properties to use in the real world to build a solar cooker which will concentrate the sun’s rays (and heat) to a point where you can “cook” food.

Your task is to design and construct a parabolic dish solar cooker using what you know about parabolas. It will be tested by trying to catch the sun’s rays on a sunny day by placing a marshmallow at the focus and trying to get it to catch fire quickly and/or measure the highest internal temperature. The dish should be no more than 2 feet in diameter. Do not go out and buy a mirror! That’s cheating! The dish should have some way of supporting a marshmallow at the focus for cooking. Run ideas by me for other materials for your reflective surface.

Suggested Materials: / Provided by DCMST
·  Aluminum Foil / ·  Marshmallows
·  Ruler and tape / ·  Temperature Probe
·  Bowl / ·  Graham Crackers
·  Ball cut in half / ·  Hershey Bars
·  Pipe Cleaners/Coat Hanger/Toothpicks / · 
·  Box – optional (you must provide) / · 
·  Calculator / · 

To be completed before the activity:

1. Draw and label a diagram of your parabolic solar cooker.
2. Assume the vertex is at (0,0). Use a ruler to locate the “coordinate” of another point on your parabolic solar cooker. Plug this point into and solve for a. Write the equation of your parabola below.

y =

3. Use your equation to find the distance to the focus point. Record c below.

c =

To be completed during the activity:

4. When you are ready to begin cooking, place the marshmallow at the focus point and begin recording the time until the marshmallow catches fire.

Time:

5. When your marshmallow catches fire, record the temperature of the center of the marshmallow with a temperature probe. If your marshmallow never catches fire, record its final temperature.

Temperature:

Rubric:

Note: Groups that set fire to their marshmallow receive extra credit! Have fun!! J

Design
Meets specification of design / 0 / 1 / 2 / 3
Holds shape / 0 / 1 / 2
Achieves cooking temperature / 0 / 1 / 2
/ 7
Worksheet
Diagram / 0 / 1 / 2 / 3 / 4
Equation / 0 / 1 / 2 / 3 / 4
Focus Location / 0 / 1 / 2 / 3
Time/Temperature / 0 / 1 / 2
/ 13
/ 20

Group members:

Name: ______Date: ______Hour: 1 2 3 4 5 6

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