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Project Summary

Difficulty	4  –  5
Time required	Very Short (a day or less)
Prerequisites	None
Material Availability	Specialty item
Cost	Low ($20 - $50)
Safety	No issues

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Sponsor

Sponsored by a generous grant from Seagate

Objective

The goal of this project is to investigate the effect of material properties on shock levels and protection against shock damage.

Introduction

Products we use every day come in all shapes and sizes. Most products come in some type of packaging to protect them from damage while they are being transported. Companies spend a lot of money on designing the right package for their product.

This experiment is meant to help you explore how material properties such as hardness and weight can affect shock levels observed during drop testing. The material properties of the product being dropped, the packaging, and the surface it is being dropped onto are all important in determining the amount of shock received. This project is intended to help you understand what types of material make effective and cost effective packaging to protect products from damage.

Terms, Concepts and Questions to Start Background Research

To do this project, you should do research that enables you to understand the following terms and concepts:

• standard measure for material hardness,
• comparison of hardness for common materials,
• measuring shock amplitudes,
• common packaging materials and their cost.

Questions

• Do you think dropping your product on a hard floor from 1 foot would cause more damage than dropping your product on a carpeted floor from 4 feet?
• What would be a realistic drop distance for your product to survive during shipping? How about after shipping, once it has been removed from its packaging? For example, is it reasonable to expect a product to withstand a drop of 10 feet?

Bibliography

• NPL, 2006. "What are 'g-forces' and are they caused by gravity?" National Physical Laboratory, U.K. [accessed March 22, 2006] http://www.npl.co.uk/force/faqs/gforces.html.
• This is a high-school level tutorial on free fall and the acceleration due to gravity:
  Henderson, T., 2004. "Introduction to Free Fall," The Physics Classroom, Glenbrook South High School, Glenview, IL [accessed March 22, 2006] http://www.glenbrook.k12.il.us/gbssci/phys/Class/1DKin/U1L5a.html.

Materials and Equipment

To do this experiment you will need the following materials and equipment:

• 3 samples of material or an object to be dropped (examples below). You may want to use multiple sizes/weights of each of these:
  • rubber,
  • wood,
  • metal,
  • styrofoam.
• 3 samples of various surfaces to be dropped on (examples below):
  • wood,
  • concrete,
  • foam,
  • pillow,
  • carpet,
  • tile.
• 3 samples of material to be used in packaging (examples below):
  • bubble wrap,
  • packing peanuts,
  • tissue,
  • styrofoam,
  • plastic filled with air,
  • newspaper.
• packaging container (choose 1— examples below):
  
  • cardboard box,
  • large plastic (i.e. Ziploc) bag,
  • shipping envelope.
• tape measure or ruler,
• tape,
• chair or ladder,
• 1–2 resettable shock indicators (50 G level) search Web for these, example brand names are "Drop-N-Tell" and "TelaDrop" (see Variations section for possible alternatives).

Experimental Procedure

1. Set up your materials and equipment for testing.
   1. Determine the material(s) and size(s) of product you plan to drop.
   2. Identify the 3-4 surfaces you plan to use to drop the product onto. You can choose to go to the location of the surface or, if it is portable (e.g., a small sample of carpet, wood, etc.), then collect the samples and bring them to one central location for testing.
   3. Create a table listing the variables (material, size, and surface).
   4. Secure the tape measurer or ruler in a vertical position against a non-movable surface like a wall. (This will allow you do your experiment using two hands.)
   5. Tape the resettable shock indicators to one side of the first product you are dropping.
2. Predict the outcome of the drop testing.
   1. Formulate a hypothesis about how you expect the material type, material size, or surface type to affect the distance the product can be dropped before it activates the shock indicator.
   2. For example, your hypothesis might be "I think a smaller piece of X when dropped on a surface of Y will activate the shock indicator at the shortest distance from the surface."
3. Determining the shock threshold of product on each of the various surfaces.
   1. Take your first product and first surface and drop the product from 1 foot above the surface.
   2. Verify whether shock indicator was activated.
   3. Record material, surface, and shock activation (yes/no) in the table.
   4. If shock indicator was not activated, then increase distance (you can decide what interval).
   5. Repeat the experiment and record the results.
   6. Continue until you get to a level where the shock indicator is activated.
   7. Repeat the experiment with the remaining surfaces, making sure you reset shock indicator each time it is activated.
   8. Repeat the entire experiment with second and then third products selected. Test against all three surfaces.
4. Summarize your findings and compare them to your predicted results. What did you learn?
5. Predict the outcome of testing with different packaging materials.
   1. Formulate a hypothesis about how you expect different packaging material to affect the distance the product can be dropped before it activates the shock indicator.
   2. For example, your hypothesis might be, "I think using bags filled with air will protect the product at higher drop distance than using tissue."
6. Test various packing materials.
   1. Choose the packaging materials you will be using.
   2. Create a table for recording the packaging material, the distance dropped, the surface it is dropped on, and whether the shock indicator was activated or not.
   3. Choose one of your product samples from your first experiment, place it in your packaging container, and fill the container with the first packaging material.
   4. Make sure that the packaging material completely surrounds the product.
   5. Tape the packaging container closed.
   6. Choose one surface to perform your experiment on (perhaps the 'worst case' from your first experiment).
   7. Drop your package from the same distance that had previously activated the product in the first part of this experiment. Record whether the shock indicator was activated or not.
   8. If not, continue to increase the distance and repeat the experiment until the shock indicator is activated. Record your results after each drop.
   9. Repeat the experiment with other packaging materials and record the results.
7. Summarize your findings and compare them to your predicted results. What did you learn?

Variations

• An alternative to using the shock indicators would be to use:
  • an egg, or
  • an impact-activated sound toy, or
  • an impact-activated lighted toy (you would need to be able to see through the packaging to know if the light was activated).
• Determine how small the product packaging can be and still protect the product at the desired drop distance—packaging does cost money.
• Renewable resources and packaging. Do research on the materials commonly used in packaging. Which materials can be made from renewable resources? Can renewable materials effectively protect against shock? Would using renewable materials add to the cost (e.g., if more material is needed to provide effective protection)?

• For more science project ideas in this area of science, see Mechanical Engineering Project Ideas.

Credits

Seagate Technology

Edited by Andrew Olson, Ph.D., Science Buddies

Last edit date: 2006-10-24 01:00:45

Career Focus

If you like this project, you might want to think about career opportunities in Mechanical Engineering.

Mechanical engineers are part of your everyday life, designing the spoon you used to eat your breakfast, your breakfast's packaging, the flip-top cap on your toothpaste tube, the zipper on your jacket, the car, bike, or bus you took to school, the chair you sat in, the door handle you grasped and the hinges it opened on, and the ballpoint pen you used to take your test. Virtually every object that you see around you has passed through the hands of a mechanical engineer. Consequently, their skills are in demand to design millions of different products in almost every type of industry. Learn more about this career: Mechanical Engineer.