Can you place a banana in a bottle without using your hands? Amaze your friends with this party-trick science experiment. Watch carefully, because the banana is quicker than the eye in this split-second surprise. Moreover, it all has to do with molecules and air.
Things Required:
1/2 banana, peeled
Tea kettle with boiling water
A clean, long, narrow bottle (with banana-size mouth)
Funnel dish towel
Directions:
Put the funnel into the bottle neck and carefully fill the bottle almost to the top with boiling water (an adult’s help recommended). Remove the funnel. Wrap a dish towel around the bottle and gently swirl the water around; then pour it out. Quickly, fit the pointed end of the half-banana downwards into the bottle neck so that it may make an airtight plug. (Watch the variables-the size of the banana and bottle neck, the amount of hot water, the time it takes-and be patient! You may have to do this experiment several times to get it right, but you will succeed!)
This Is What Happens:
The banana is sucked down into the bottom of the bottle.
Science Behind It:
The heat from the boiling water causes the air inside the bottle to expand, forcing some of it out. When the banana is placed into the mouth of the bottle and the cooling air inside the bottle shrinks again, the air pressure inside is reduced, and the greater air pressure outside shoves the banana ahead of it into the bottle. This gives you an idea of what happens when air is removed from a space and nothing takes its place (partial vacuum). Just small differences in air pressure can cause things to move.
