I.
Title: Influence of Simply Holding Nutritional Foods on Muscle Strength
Recommended Grade Level: 6th – 8th
Subjects: General Science
Author: Trisha Doshi
School: Whitewater Middle School

II.
Objective: Students will be able to apply the scientific method to an experiment involving muscle strength.

Related State or National Science Education Standards

A.8.1 Develop their understanding of the science themes by using the themes to frame questions about science-related issues and problems.

A.8.3 Defend explanations and models by collecting and organizing evidence that supports them and critique explanations and models by collecting and organizing evidence that conflicts with them.

A.8.7 Design real or thought investigations to test the usefulness and limitations of a model.

III.
Equipment or Materials Needed
1. Various weights to hang on arm. (different students will be able to hold different weights)
2. Tape to mark place on arm to hang weight.
3. Screen to block view when objects are placed in bags.
4. Paper and pen to record results.
5. Many food items of varying nutritional value. (candy, soda, chips, orange juice, milk, apple etc.)
6. Unmarked bags to hold items.

IV.
Procedure
   

Prepare the class by explaining the following:
    Each experimental subject will hold one arm out to the side at shoulder height. A piece of tape will mark a place on the forearm where the weight will always be hung. A classmate will hang a weight on that arm. This will indicate the amount of weight that the arm can hold without being lowered. The experimental subjects are told to keep their arm straight and not let the weight pull it down. When the weight that they can hold is established, they put their arm down for a rest. A class mate will hand one of the food items to the subject who will hold it in front of their own stomach, their other arm will be extended again, the weight hung on it to see if the subject can still hold the weight on the arm at the same height. Record the results. Do this with the rest of the subjects.

V.
Assessment

    Students will complete a lab report including the following:
1. Purpose
2. Materials
3. Procedures
4. Observations
5. Conclusion

Additional information.

The purpose is to have the students discover the variables that need to be controlled to complete this experiment using the most scientific method. The claim is that nutritional food will allow the extended arm to remain held horizontal to the floor. (muscles remain unaffected) Foods that are not nutritional will make the arm go down. (weakening the muscles) Lead students to the idea that the best way to do this is to have the food in bags or boxes that are of similar shapes, sizes and weights. The bags or boxes can be marked with letters by a control person who records this information. This information is not made available to the experiment subjects until the results are to be interpreted. Discuss with the students the importance of not knowing what is in the bag or box. Perhaps the concept of a double blind study can be explained.

Part of the experiment can be what the affect of knowing what is in the bag or box. If you know it is nutritious, does this affect your arm muscles? If you know it is not nutritious, ie. candy, does it affect your arm muscles? I have done this using just my hand to push down on the subject’s arm like is shown in the picture. To eliminate the possibility of error and arms getting tired, the use of weights was suggested. This can be discussed with students also.