Put a lit candle behind abottle. If you blow on the bottle from the opposite side, the candle may goout, as if the bottle was not there at all. Explain the phenomenon.
A Sound Tube is a toy,consisting of a corrugated plastic tube, that you can spin around to producesounds. Study the characteristics of the sounds produced by such toys, and howthey are affected by the relevant parameters.
Fata Morgana is the namegiven to a particular form of mirage. A similar effect can be produced byshining a laser through a fluid with a refractive index gradient. Investigatethe phenomenon.
A bowl with a hole in itsbase will sink when placed in water. The Saxons used this device for timingpurposes. Investigate the parameters that determine the time of sinking.
Put a string through aball with a hole in it such that the ball can move freely along the string. Attachanother ball to one end of the string. When you move the free end periodically,you can observe complex movements of the two balls. Investigate the phenomenon.
A heavy particle may fallthrough a horizontal soap film without rupturing it. However, a light particlemay not penetrate the film and may remain on its surface. Investigate theproperties of such a membrane filter.
Under certaincircumstances, the “flea” of a magnetic stirrer can rise up and levitate stablyin a viscous fluid during stirring. Investigate the origins of the dynamicstabilization of the “flea” and how it depends on the relevant parameters.
A line drawn with apencil on paper can be electrically conducting. Investigate the characteristicsof the conducting line.
畫出來的導(dǎo)線
用鉛筆在紙上畫的線可以導(dǎo)電。研究這種導(dǎo)線特性。
11. Drifting Speckles
Shine a laser beam onto adark surface. A granular pattern can be seen inside the spot. When the patternis observed by a camera or the eye, that is moving slowly, the pattern seems todrift relative to the surface. Explain the phenomenon and investigate how thedrift depends on relevant parameters.
A stationary cylindricalvessel containing a rotating plate near the bottle surface is partially filledwith liquid. Under certain conditions, the shape of the liquid surface becomespolygon-like. Explain this phenomenon and investigate the dependence on therelevant parameters.
A massive object isplaced onto two identical parallel horizontal cylinders. The two cylinders eachrotate with the same angular velocity, but in opposite directions. Investigatehow the motion of the object on the cylinders depends on the relevantparameters.
Identical discs arestacked one on top of another to form a freestanding tower. The bottom disc canbe removed by applying a sudden horizontal force such that the rest of thetower will drop down onto the surface and the tower remains standing.Investigate the phenomenon and determine the conditions that allow the tower toremain standing.
If you take a salt orpepper pot and just shake it, the contents will pour out relatively slowly.However, if an object is rubbed along the bottom of the pot, then the rate ofpouring can increase dramatically. Explain this phenomenon and investigate howthe rate depends on the relevant parameters.
Place a nitinol wire looparound two pulleys with their axes located at some distance from each other. Ifone of the pulleys is immersed into hot water, the wire tends to straighten,causing a rotation of the pulleys. Investigate the properties of such anengine.
A standard playing cardcan travel a very long distance provided that spin is imparted as it is thrown.Investigate the parameters that affect the distance and the trajectory