Marshmallow expands then shrinks.
Ask students to predict what will happen. Pump air out, then let air back in.
Key idea: Lower outside pressure lets trapped gas pockets expand.
Ask: What is pushing on the marshmallow normally?
Safety and cleanup: No eating afterward; use safe vacuum container.
Food & Kitchen Items
Marshmallows
Peeps
Gummy bears
Whipped cream
Shaving cream (technically soap, but great for kitchen-scale jars)
Warm water (to watch it boil at room temperature)
Carbonated soda
Champagne or sparkling cider
Sliced watermelon
Sliced cucumbers in pickle brine (for instant pickling)
Apples (they turn translucent as air leaves the cells)
Strawberries
Bread or cake slices
Eggs (uncooked, in the shell)
Unpopped popcorn kernels
Ice cubes
Chocolate syrup
Honey
Balloons & Inflatables
Partially inflated rubber balloon
Balloon animal
Foil helium balloon
Bubble wrap bubble sheets
Plastic baggie filled with a tiny bit of air
Closed empty plastic water bottle
Ping pong ball (with a tiny pinhole)
Foam earplugs
Electronics & Household Gadgets
Alarm clock (to hear the sound fade away in a vacuum)
Bluetooth speaker playing music
Plasma globe (changes the behavior of the electrical arcs)
Incandescent light bulb with the glass globe removed (filament burns out instantly)
Neon glow sticks (snapped and glowing)
Suction cup stuck to a smooth surface (it will detach)
Toys & Novelties
Slime
Silly Putty
Orbeez / Water beads
Memory foam squishy toy
Shaving cream beard on a action figure
Soap bubbles
Kinetic sand
Liquids & Chemicals
Liquid soap
Isopropyl alcohol (boils incredibly fast)
Cooking oil
Wet paint
Acetone
Silicone or epoxy resin (to remove air bubbles)
https://www.flinnsci.ca/globalassets/flinn-scientific/all-free-pdfs/dc91705.pdf