Don't Pin Me Up! What is the sharpest cactus in the Sonoran Desert?
Plants and the Environment- Grade:
- 3
- Teacher:
- Jennifer Lampano
I wanted to find out what is the sharpest cactus in the Sonoran Desert after I saw YouTube nature guy, Coyote Peterson, fall into a Teddy Bear cholla and said it was very painful. I hypothesized the Teddy Bear cholla would be the sharpest. I tested 9 cacti collected across 3 spots around Tucson, a tooth pick, and a sewing needle to see which was the sharpest, defined as the ability to pierce and puncture. I tested sharpness by whether or not it could cut tissue paper, puncture a cork, puncture fake skin, and if the fake skin stuck to the cactus when tossed. My hypothesis was wrong because the Fishhook Barrel Cactus had the sharpest thorn because it cut and punctured the best. This project is important because we live in the Sonoran desert, and we need to know what cactus to avoid.
This was an outstanding investigation! You clearly defined what “sharpness” means and tested it using multiple methods, which shows very advanced scientific thinking. I am impressed that you used control objects like a sewing needle and toothpick for comparison.
Collecting samples from different locations and identifying them carefully demonstrates strong research skills. Keep exploring the natural world with curiosity and careful testing, you are thinking like a true scientist!
Your project was fun to read and very well planned. You asked a clear question, explained what “sharpest” means, and tested many different cacti from different places using several smart tests. I liked that you included a toothpick and a sewing needle as controls and that you made graphs and a results table to compare everything. Great work learning about desert plants and safety!
Nicely researched and presented project and a good choice of topic. A look at each of the spines under a microscope as you suggested might reveal why some stick to the “skin” and some don’t! Nice job! The fact that only the barrel cactus could easily be inserted in the cork was actually a good proof of sharpness… the cork was the decider really, a great way to demonstrate difference in sharpness when looking for the best of the best!