Materials You’ll Need:
- Oil: A little bit of cooking oil (like vegetable oil) will work.
- Paper: Several sheets of plain paper (A4 or letter size is fine).
- Paintbrush: A small one to apply the oil.
- Hot Chocolate Powder: Or fine cocoa powder, or even dark-colored spice like cinnamon (ask your facilitator). This will “develop” your print!
- Paper Towels or Cloths: For wiping your oily shoe.
- Pen or Marker: For labeling your prints.
- Tape: To hold paper down if you’re making action prints.
- Camera: A phone camera is perfect.
- Ruler: To use as a scale in your photos.
- Your Shoe: You’ll only need one of your shoes for this experiment. Pick one with an interesting sole!
Let’s Get Experimental! (Following the Video Steps)
Get ready to make some impressions!
1. Prepare Your Shoe
- Using your paintbrush, carefully apply a thin, even layer of oil to the entire sole of your chosen shoe. Make sure to get oil into all the grooves and patterns, but don’t put so much on that it’s dripping.
2. Make Your Standing Prints
- Place a clean sheet of paper on a flat, hard surface.
- Carefully step onto the paper with your oiled shoe. Try to do this in one smooth movement, then step off.
- Safety First! As soon as you step off, thoroughly wipe the oil off the sole of your shoe with a paper towel or cloth. An oily shoe is a slippery shoe!
- Now, to make your oily print visible: Gently sprinkle the hot chocolate powder all over the area where you stepped.
- Carefully tilt the paper and tap it so the excess powder falls off. You can also gently blow away any remaining loose powder. An image of your shoeprint should now be clearly visible!
- Label this print with your pen/marker: “Standing – Print 1”.
- Repeat this entire process (oiling the shoe if needed, stepping, wiping, developing with powder) on a new sheet of paper to create a second standing print. Label it “Standing – Print 2”.
3. Action Prints! (Choose AT LEAST ONE Action)
The way you move can change how your shoeprint looks. Let’s investigate!
- Choose at least ONE of these actions to make prints for:
- Setup for Action Prints:
- If you’re making running or jumping prints, it’s a good idea to do this outside on a smooth, flat surface where you have some space and less chance of slipping (once your shoe is wiped clean, of course!).
- It can be helpful to have a friend assist you. For running or jumping, you might want to mark a starting line. Do a test run/jump (without oil first!) to see roughly where your foot will land.
- Place a clean sheet of paper where your foot is likely to land and tape it down securely so it doesn’t slide.
- Make the Action Print:
- If necessary, re-apply a thin layer of oil to your shoe sole.
- Perform your chosen action (walk, run, or jump), aiming to land your oiled shoe on the taped-down paper.
- Carefully lift your foot.
- Important: Wipe your shoe sole clean immediately and thoroughly!
- Develop the print on the paper using the hot chocolate powder, just like you did for the standing prints.
- Label and Repeat:
- Label your print clearly with the action you performed (e.g., “Walking – Print 1”, “Running – Print 1”, or “Jumping – Print 1”).
- Create at least two prints for your chosen action. For example, if you chose walking, make “Walking – Print 1” and “Walking – Print 2”.
4. Document Your Evidence with Photos
In forensic science, good documentation is crucial!
- Photograph Your Shoe:
- Take clear photos of the shoe you used for the experiment. You’ll need pictures of:
- The Left Side
- The Right Side
- The Top (looking down on it)
- The Sole (this is a very important one!)
- When you take these photos, place your ruler next to the shoe so it’s visible in the picture. This provides a scale.
- Photograph Your Prints:
- Take clear photos of each shoeprint you created (your standing prints and your action prints).
- Again, place your ruler next to each print when you photograph it.
- Photo Tip: For the clearest photos, lay the shoe or print flat on the floor. Try to hold your camera directly above it (at a 90-degree angle). If you have a small tripod or something to steady your phone, that can help!
5. Analyze Your Findings!
Time to put on your forensic scientist hat and examine your evidence!
- Compare the photos of your shoe’s sole to the photos of the prints you made.
- Matching: Is it easy to see that the prints came from your shoe?
- Find the Details: Look for any distinguishing marks or wear patterns. These are unique features like small cuts, nicks, unusual wear on the heel or toe, or even tiny pebbles stuck in the tread that might have transferred to your prints. Can you spot any of these “individual characteristics”?
- Measure Up: Using the ruler in your photos as a guide (or by re-measuring the actual prints/shoe if needed), measure a few distinct features on your shoe’s sole (like the length of a logo, the width of a main tread block, or the distance between repeating patterns). Now, try to measure the same features on your prints.
- Are the measurements identical? How close are they?
- Reflect on the Process:
- How accurate do you think comparing a print to a shoe can be based on this method?
- Did you notice much difference (variability) between your two “Standing” prints? What about between your two prints for the action you chose (walking, running, or jumping)?
- If you made prints for different types of actions (e.g., standing vs. walking), how do they compare? Does the force or motion of the action change how the print looks?
6. Share Your Discoveries! 🖼️
- You’ll be uploading photos of your shoe sole and at least two of your best shoeprints (for example, one standing print and one action print, or two different action prints if you made them) to the class Padlet below.
Why This Matters: The STEM Connection 💡
- This experiment gives you a peek into the world of forensic science and how investigators analyze footwear impression evidence found at crime scenes.
- You’ve used important scientific skills like careful observation, precise measurement, comparison, critical thinking, and documentation.
- Understanding how shoeprints are formed, how they can vary depending on activity, and how to identify unique characteristics is vital for accurately interpreting this type of evidence.
- This work connects to university fields like Forensic Science, Criminology, and even Physics (which helps explain the forces involved in making an impression).
Great job on your forensic investigation!