Ever notice how cereal clumps up in your bowl, or how cereal sticks to the edges of the bowl? Bubbles in beverages do the same thing.You’ve probably seen this surface tension and buoyancy at work, but did you know there’s some mind-blowing science behind it? What we learn in our cereal bowl even connects to the lives of tiny insects that walk on water. Continue reading
Here’s STAO’s own Otto Wevers using his fascination with cycling to conduct an experiment to the test the buoyancy of his fat tire bike.
The following experiment will give you insight into the role air pressure plays on weather and help explain how airplane wings get ‘lift’. Have you ever put your hand outside the window of a moving vehicle? As you are doing this, hold the palm of your hand flat or parallel to the ground and slowly rotate your hand until it is perpendicular to the ground? Did you notice that with a slight rotation of your hand, as the wind hits your palm, your hand was forced up by the wind? This is what will happen to the balloon as the air from the hair dryer passes over the balloon’s surface. The balloon is hit by the flowing air, which flows around the outside surface of the balloon, pushing the balloon into the centre of the air column created by the hair dryer. The balloon with receive lift until gravity exceeds the force being applied by the air from the hair dryer. As the balloon sits in this stream of air created by the balloon, a low-pressure area is created on the opposite side of the source of the air flow, leaving an ‘empty’ space behind the balloon. It is there because the wind is being blocked by the surface of the balloon. The air rushing over the balloon turns to fill up the low-pressure space, and then tries to keep on going—out the side of the main column. As the jet of air rushes ‘out’ over the surface of the balloon, it is pulled back onto the opposite side of the balloon, keeping the balloon inside the air column generated by the hair dryer.
Students should already have had some previous experiences with solids and liquids. This activity allows the students a chance to observe buoyancy and interactions of solids with liquids. They can investigate and describe the properties of density, as well as adhesive/cohesive forces. The usage of common table foods creates high interest.
You throw a rock in water from your boat. Can you figure out what happens to the water level?
By Steve Spangler.
A Solar Bag is a long plastic bag made from a very thin plastic and colored black to absorb solar energy. The heated air inside the bag provides buoyancy and causes the bag to float. Continue reading
Scientists seem to be infatuated with objects that float and sink. Even non-scientists find great joy in dropping stuff in water to see if it floats or sinks. Fans of David Letterman are quick to point out one of Dave’s favorite segments called, “Will It Float?” Here’s the latest float or sink challenge: Why do lemons float in water but limes sink? Think you know the answer? Not so fast…
About Steve Spangler Science…
Steve Spangler is a celebrity teacher, science toy designer, speaker, author and an Emmy award-winning television personality. Spangler is probably best known for his Mentos and Diet Coke geyser experiment that went viral in 2005 and prompted more than 1,000 related YouTube videos. Spangler is the founder of http://www.SteveSpanglerScience.com, a Denver-based company specializing in the creation of science toys, classroom science demonstrations, teacher resources and home for Spangler’s popular science experiment archive and video collection. Spangler is a frequent guest on the Ellen DeGeneres Show where he takes classroom science experiments to the extreme. Check out his pool filled with 2,500 boxes of cornstarch!
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