LSOP Live: Sinking and Floating, February 12, 2021
A bowling ball—does it sink or float? The answer might surprise you, as will dozens of the experiments we share. We float bubbles and steel balls, and make a ketchup packet go back and forth between sinking and floating. We answer the question: What happens to buoyancy when you turn off gravity? And we leave you with a bunch of investigations you can try yourself. Join us for a fun and floaty time!
Sinking and Floating Shorts
Normally, bubbles sink to the ground and pop upon impact. But what if you float them on smoke? The smoke here is more dense than the air inside the bubble, causing the bubble to float nicely on the top.
Did you know that chickens can float on water? Like ducks, chickens weigh much less than the water they displace, making their bodies buoyant. Watch these lovely chicken friends go for a swim!
Buoyant force depends on gravity. As our duck enters a free fall, buoyant forces are temporarily turned off causing the only force on the duck to be the spring. The spring therefore pulls the duck down to the bottom of the jar as it falls.
Think about what happens when a car speeds off quickly. Normally, your head is whipped backwards as the car moves in the forward direction. However, in water it is a bit different. Watch the duck be pushed forward along with the forward moving water.
Using these density bottles, we can make isopropyl alcohol and water “unmix” just by adding salt. The salt increases the density of the water, causing the mixture to separate into two distinct layers!