The first one (?liquid density thermometer?) is a really good start to what I think could be a super image. For me, the top of the bottle really doesn't do much to enhance the image so that needs to go either with a re-shoot or a crop. A crop would still have that 'shooting down on the subject' kind of look though. But wow - those colored vessels inside the water really make me curious to try and shoot that.
Maybe consider some sort of back light of the vessel and focus on the inside colors in fluid? For a back light concept, think of setting it in a window sill with sunlight coming through, or on a table outside with the sun behind it. Or maybe an LED flashlight shining on it. Get those colors and inside contents to really "pop" with color in that water. And get down at the objects level (or a trick is shoot it on something taller so you don't have to bend down!)
The top is cool. Just from a mechanical perspective, they are interesting items, and I like how you focused on the brighter part towards the front. There's just enough DOF to know what else is part of the top too. And you did well IMO by placing it on a aged surface instead of a smooth one. Adds to the 'character'.
The pinecone? Not doing much for me. Again, the angle of shooting down at the object is a turn-off for me. If you just have to shoot that thing, try getting even with it and fill the entire frame with it. That would certainly make it a tad bit more interesting for me at least.
You're off to a good start!