21. On The Underside Of Our Cabinet In The House We Recently Bought, Built In The 70s. Plastic With Metal Teeth On One Side, Very Dull. Each Side Is ~4 Inches Long. What Is This Thing?
Answer: Jar opener
22. This Rainbow Effect?
Answer: A rainbow is a rainbow. The cause is refraction/dispersion of light due to water in the air.
Looks like it’s raining over there. The shape is just a matter of angles and height.
23. What Are Those Things Called? I Think They’re Typical Of Gothic Architecture?
Answer: Flying buttresses. They’re there to transfer the weight of the roof outwards to stop the walls bowing and collapsing.
24. Found This In My House. I Bet My Wife It Has Something To Do With A Tie. Do I Win?
Answer: Hoof pick for cleaning horses hooves.
25. What Is This Fiber/Sand Ball? Found Among Thousands Like It On A Beach In Spain. It Weighs Almost Nothing
Answer: Sea grass ball
26. What Are These Circular Metal Things On These Stairs? I Just Hit My Knee And Goddamn Did It Hurt
Answer: Skateboard prevention device. Keeps em from grinding on edges.
27. Plaque With Numbers Inscribed On It. Found On The Sidewalk Outside A Building At My University
Answer: Magic square. It’s a popular sort of decoration to put outside math departments
28. Saw This Rusty Thing On My Walk In A Forest. The Forest Belong To A Estate Wedellsborg, Vestfyn, Denmark. What Is This Thing?
Answer: It is an underwater mine
29. I Found This Hanging From The Basement Rafters Of My 100 Year Old House. It Appears To Be Two Marbles Or Something Similar In A Hanger Of Some Sort. Any One Have A Clue What This Could Be?
Answer: It’s a razor blade sharpener. A 1930s salesman’s special and it doesn’t even sharpen the blades just realigns the edge and gets you a few more shaves.
30. Found In A Crawlspace Of A House From The 80’s Next To 3 Red Boxes Encased In Concrete. What Is This Thing?
Answer: This label is used for materials with gamma and neutron emissions This label was specifically used on containers shipped by aircraft, and that reference is from the late 50s/early 60s. Any red label is going to be Group I or II, which as stated above emits gamma rays, neutrons, or both, and is potentially harmful even with the box closed. OP’s lid came from something shipped by air, but it’s interesting to note that on ground shipments of the same class of materials (like with the label variant I found in my first edit), the trucks themselves were required to be marked “CAUTION” or “DANGEROUS – RADIOACTIVE MATERIALS” on the sides and rear of the vehicle just to haul this kind of material.
Post author update: As of today a 3 man team from the state of Utah department of environmental quality, division of waste management and radiation control, uranium Mills and radioactive materials section (holy [crap]) showed up at my friend’s house around 10am and spent a few hours taking readings, swabbing samples and asking questions and after all of that, found nothing but natural trace amounts of radon. The “lid” they think was from the late 1950’s and was unrelated to the “vault”.