WHAT WILL YOU MAKE?
WHAT WILL YOU NEED?
- A cardboard box no larger than 1'x1'x1'
- A pair of nylon leggings
- Soft materials (such as crumpled paper, packing foam, padding, or plastic bags full of air)
- A smart phone with Google's Science Journal app installed, preferably an older, non-primary phone
- A standard-height table or desk
Create a Baseline
To minimize impact on the phone, use some padding, foam, or other soft “found” items in the box or on the landing surface. (We opted for no padding in our initial test.)
Start a new Science Journal app experiment and select the Z Accelerometer sensor. Start recording and place the phone in the box. Wait a few minutes for the data to smooth out, making it easy to ignore the point when you placed the phone in the box.
Seal the box and then drop it off the table. Don’t drop it from too high as it might damage your phone, even in the box. You should be able to see in the app the point where the box and the phone hit the floor. This is our baseline data. Now let’s see if we can smooth that impact out a little.
Construct a Hammock
Using a pencil, poke one hole on each of two opposing sides of the box. Start recording, place your phone into the leg of the nylon leggings, and set it in the box. Thread one end of the nylons through one of the holes, and tie a knot on the outside of the box to keep it from slipping back through. Repeat on the opposite side, lifting the phone off of the bottom of the box when tying the leggings off. If your phone does not lie in the hammock with the back of the phone facing down, you may need to adjust which accelerometer is being used. My phone tipped on its side because of the internal weight distribution, so I set it up to record on the X-axis.
Now seal up the box and drop it again. How do you think the impact forces will change?
Test 1 on the left shows the result of the phone dropping without any padding in the box. Test 2 shows the phone in a hammock, and the much smoother acceleration graphs when the phone is protected.
We can see that the average acceleration has decreased and the maximum has greatly decreased. Note also how the hammock has a smoother overall graph.
Can you make something that works better than our box? Use your creativity and additional materials you have to try more tests. How do your readings look if you run the accelerometer in the X- and Y-axes, and do any of the suppression methods affect those readings?
Try drawing graphs that show your prediction of how other materials might affect your drop. After a few experiments, can you look at a graph and make an educated guess if it was protected or not?
Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Power tools, electricity, and other resources used for these projects are dangerous, unless used properly and with adequate precautions, including safety gear and adult supervision. Some illustrative photos do not depict safety precautions or equipment, in order to show the project steps more clearly. Use of the instructions and suggestions found in Maker Camp is at your own risk. Make Community, LLC, disclaims all responsibility for any resulting damage, injury, or expense.
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