We drew food webs for our backyard (including our dog and lizards… she really eats lizards).
We looked at a torn blade of grass under the microscope.
We looked at rhizobacteria under the microscope.
We made a terrarium in an empty pickle jar.
We picked two identical leaves off one tree. We put 1/2 cup of distilled water in one jar and 1/2 cup distilled white vinegar in another jar and added a leaf to each jar. We let them sit overnight. The next day, the leaf that had been in the water was bright green and still looked healthy while the leaf that had been in the vinegar was very dark green and a bit shriveled.
We planted four radish seedlings and watered one with pure water, one with pure vinegar, one with 4 parts water and 1 part vinegar, and one with 4 parts vinegar and 1 part water. The one with pure water kept growing, the one with pure vinegar died within a few hours. The one with mostly water tried to keep growing, but wasn’t healthy, and the one with mostly vinegar grew for a couple days and then died.