This idea is built off Paloma's Student Designed Labs using objects found in the classroom, and is appropriate for all grade levels.
Scientific phenomena are naturally occurring or man-made observations that we can use our science knowledge to explain or predict. The image above shows Tears In Space. Phenomena-based learning requires students to use the 3-D learning model (Science and Engineering Practices, Crosscutting Concepts, and Disciplinary Core Ideas) to explore, investigate, and explain how and why phenomena occur.
The NGSS website has begun a collection of phenomena teachers can use, applicable for a variety of ages (https://www.ngssphenomena.com/). Although I teach secondary science, I believe the science taught at the elementary level is the most crucial. Kids are born naturally curious creatures; we need to support that curiosity, and not kill the wonder. Phenomena do not need to be phenomenal to be effective, although I think some people would be surprised at what the kids "oohh and ahhh" at.
Take some raisins, throw them in a cup of Mountain Dew, tell your kids you found sewer lice, and you will get older students' attention as well as the younger ones. Well you may not hear "oohh" more likely "ewww", but I love that sound too. And the best part is, it can be as easy as accessing some of these images off the website or replicating quick and easy demonstrations yourself.
At the elementary level, it is important to have your students begin just by asking lots and lots of questions to phenomena. The more the better. As students get older, we should model how to refine and start asking even better questions. Teachers can help students at any age examine the questions they have created and transform them into questions that that are testable. Once they have identified an appropriate, testable question, Voila-La, they have begun the Scientific Method, and will be well on their way to designing an inquiry-based experiment .