Hi theodoremorse,
If you are asking this question regarding the materials for the SciBuddies project "Dog Toys: What Makes One a Favorite or a Flop to Fido?," the materials tab puts down specifics regarding which materials to use:
https://www.sciencebuddies.org/science- ... #materials
12 dog toys: Select four toys for each experiment listed below. Choose three toys you predict your dog will like and one toy you think will be unappealing to him/her in each experiment.
Experiment 1. Interactive (balls that bounce, squeaky toys, rattles, toys that light up or make music)
Experiment 2. Different Shapes (sticks, balls, frisbee, cubes, plastic bottles or jugs)
Experiment 3. Different Textures (soft plush, hard rubber, leather, canvas toys of similar sizes/shapes)
Experiment 4. Favorite Four (use four favorite toys from experiments 1-3)
If you have any more questions related to specific toys used in each experiment, don't hesitate to ask!
-JSK