Make a Hail-Pad Without Any Styrofoam or Foil!

In accordance to one of the Citizen Science challenges from SciStarter.com,  it describes to create an inexpensive and efficient type of hail-pad for organizations such as the CoCoRaHS, that can accurately display the size, orientation and number of hailstones throughout a hailstorm. This challenge caught my eye and prompted me to try and develop my own alternative design of a hail pad without any Styrofoam and foil, as apparently they have tripled in cost throughout the recent years (I've seen places that sell Styrofoam squares for as much as $5).
The hail-pad I designed has the ability to show size, number and direction of these hail-stones. Additionally, with the two-layer modelling clay system, it can be derived from the hail pad whether these stones were travelling at high speeds on their descent to earth, as they would expose the under-layer of clay in their imprints. This hail-pad is relatively water-proof and will not dry out due to reasons explained further in this instructable :)
In the end, creating one of these hail-pads costs roughly $2.09 AU ( NOTE: you can reduce the price significantly by $1.00 (therefore making it $1.09 AU) if you wish to not use the "two-layer clay" system but rather just one layer of clay, I believe it still provides accurate results). So without further to do, lets begin making one!

Step 1: Materials Required

For this hail-pad, you will need roughly the following:

• Two different coloured, medium-sized balls of soft modelling clay (approximately equals $1 each)
• One plastic plate (approximately $0.083)
• 20 cm of plastic wrap (approximately $0.01)

And that's really all it is!

The reason I chose modelling clay is because it is designed for handling and playing with, therefore it is not meant to harden or dry out under many conditions. Thus modelling clay appeared to be the best choice for imprinting impacts of hailstones regardless of weather and temperature.

Step 2: Creating the Layers of the Pad

This step is really straight-forward, all it requires you to do is to roll these two balls (preferably with a rolling pin) into flat circles with about a thickness of 0.5 mm-0.8 mm. These circles should just be the same size as the base of the plate. Then, simply place one of the colours into the plate's base and flatten it as much as possible. After that is completed, place the other colour of clay above this layer and similarly make it as flat and even as possible.
By smoothing out the clay, you are increasing your chances of getting more accurate readings and thus, better results.

Step 3: Applying Plastic to the Hail-Pad

This step is probably the hardest step, this requires you to create a 20 cm square sheet of plastic wrap. Then, coat the plate with this sheet and press down to eliminate any possibilities of air bubbles (using your hand may help a lot). Then, with a standard hobby knife, trim around the circumference of the clay to get rid of any excess plastic.

This can be an optional step if you please, as I tested varieties of these plates and the clay appeared to be water-proof and out of personal preference, I would not have the plastic sheet, as it provides more accurate results.

Step 4: Taking It Out Into the Real World!

Well, congratulations!! You have successfully created a cheap and efficient hail-pad for your own weather research and analysis. As I haven't been receiving any hail storms lately, I decided to create my own "imitation" of a storm to demonstrate how this hail-pad can display data of the hailstones. For greater readings of the direction of the hailstones, you can write North, South, East and West on the plate and align the plate to the correct bearings of the location the pad resides in. Make sure to keep the pad secure and in a matter of time, you will have a functioning and cost efficient hail-pad!

Note: Due to the pad being made of clay, you can possibly reuse the pads by simply re-flattening the surface of the exposed clay for later usage. Also, if you want to keep records of various readings, you can create molds from the clay and then create rubber or silicon molds of your readings!

Step 5: Final Thoughts

Overall, I'd like to thank you for viewing my instructable. Hopefully this concept may encourage science to develop a type of material similar to modelling clay that will be cheap to create and behave in a similar manner for the purpose of making hail-pads in the modern world. If you have any questions or further improvements, please do tell in the comment box below!
Thanks for reading this instructable, I hope you have enjoyed it as much as I have had making it :)