Contents:
1. Moist rupture resistance/consistence hand calibration 
2. Activities related to soil texture
       -  Guides for teaching soil hand-texturing 
       -  Real life texturing - fun activity for when your field day is rained out
       -  Visualizing the soil texture triangle
3. "PizzAbundance" estimating activity

Teaching Soil Consistence/Rupture Resistance with Snacks!
Reference: Soil Survey Staff. (2024). Field book for describing and sampling soils, Version 4.0. USDA, Natural Resources Conservation Service.

Rupture resistance is a measure of how resistant soil peds/aggregates are to rupturing or crushing. It is estimated in the field by applying force by trying to crush a ped between your thumb and forefinger. The Field Book (page 2-64) provides quantitative force values in Newtons and qualitative descriptions, such as "slight force between fingers."

This method uses items (most of which were purchased at the dollar store!) to learn the rupture resistance classes and calibrate your fingers. Instructions:
(1) treat all items like blocks/clods and crush them horizontally, not vertically
(2) estimate the amount of force required to the point of failure (i.e. when the item starts to break/give)
(3) assume all snacks are ideal 2.8 cm blocks–do not use the adjustment formula
(4) these were chosen because they had a good point of failure and are relatively temperature resistant (except Milky Way!) —for the longer list of snacks email [email protected] 

Hand-texturing soil

1. Guides 
I've been working on these hand-texturing guides for many years. Many of these tests (and some of the photos in the documents!) I learned from Dr. John Galbraith at Virginia Tech.
Introductory guide
Advanced guide

2. Real life texturing -  An exercise for connecting textures to everyday(ish) items 
We set up bowls of these: 

We tried to find soil samples that were similar in texture to those above; for example, kinetic sand is pretty similar to a loamy sand texture. 

 3. Visualizing soil texture
Use masking tape to create a texture triangle on the floor, tarp, lab bench, etc. Then, place known soil textures where they belong on the triangle. I have found that this helps the students understand how the triangle works, as well as helping them visually connect what they're feeling to each texture class. You can also do the reverse: quiz the students by giving them texture samples and having them place the samples on the triangle.

"PizzAbundance"
An exercise for learning and practicing abundance estimation in soils

Summary: Order pizzas with different combinations of toppings and have your students estimate the abundance of each topping and decide on a modifier before eating well-earned pizza. 

1. First, categorize possible pizza toppings, for example: 
Gravels = sausage, beef, bacon, olives ( we made the executive decision that olives are gravels and informed our students)
Channers = pepperoni, ham, salami, mushrooms, green peppers, spinach 

2. Formulate & order the pizzas with different combinations of toppings
We expected 15 people, so we ordered 4 medium pizzas, including a vegan and veggie pizza, and a range of difficulties for abundance estimation:
(A) Pepperoni
(B) Green peppers + olives
(C) Sausage + ham
(D) Olives + mushrooms + spinach (no cheese)
Tip 1: Avoid similar-colored toppings, such as bacon + ham
Tip 2: Combine gravel and channer toppings for more difficult estimation 

3. Go through the PizzAbundance presentation with the students
Tip 1: Keep the pizzas secret until the end of the presentation
Tip 2: If you have photos of rocky soils, those would be a great addition
Tip 3: Try to keep the presentation short so the pizza doesn’t get cold! 

4. For each pizza, have the students give: (1) size, shape, and % rock fragments for each topping (2) Total %RF (3) RF modifier, if necessary, using the correct abbreviations 
We labeled the pizzas A through D and spread them around the classroom. Each student wrote 1-3 for each pizza on their own paper. For example: 
Pizza B:
1. Channers (green peppers) 25% 
    Gravels (olives) 15% 
2. Total: 40% RF 
3. VCH (very channery) 

Tip 1: This is a great chance for students to apply the rules for rock fragment modifiers (e.g. for a mix of sizes, the largest size class is generally named) 

Tip 2: Keep in mind that you will not be able to predict abundance ahead of time. We decided that my estimations, with input from assistant coaches, would serve as our answer key. It turned out that all our pizzas were dominated by channers 

Other modifications: 
Adapt for estimating abundance of secondary carbonates or redox features: 

It’s best to connect this to actual field estimation as quickly as possible!