The Engineering and Science Fair is an annual
event in February that showcases the various engineering student
societies and research groups at the University of Florida. The fair
takes place every spring and spans two days during the Benton
Engineering Council’s Engineers Week. UF AIChE has a series of
interactive exhibits which display basic scientific concepts in ways
that K-12 students can observe and understand.
Volunteers are needed to conduct and explain
the exhibits, and anyone interested in getting involved is
encouraged to do so! The experience is not only rewarding for the
visitors but also for the volunteers working the displays.
For the past few years, from a pool of well
over 20 different organizations, UF AIChE has nearly consistently
won the visitors’ choice award and placed in judging.
features a PVC pipe with a closed valve in the middle has two
balloons attached to either end.One balloon is blown up fully; the other is blown up only
The big balloon got bigger and the small balloon got smaller.
This is because the smaller balloon has a higher pressure. This
is due to the surface tension of the balloons. This can be found
in the Young-LaPlace equation. Have you ever noticed that it is
the hardest just to start blowing up a balloon, then it gets
easier? This also applies to a baby's first breath being
difficult, as all of the alveoli are deflated.
The Coriolis Force is a force felt by a body only when it moves
in a rotating frame. Instead of moving outward in a straight
line you will “swagger” a bit. This is due to the angular
Hurricanes begin as a wind full of hot dry air.As they move across the ocean, they pick up water.The Coriolis force causes it to begin to turn spin
counter clockwise in the Northern hemisphere and clockwise in
the Southern hemisphere.
By mixing the bubble solution with glycerol we increase the
increases the “stickiness”, and allows us to make interesting
shapes with the wire frames.
The bubble changes shape to minimize surface area.The bubble solution doesn’t want to be in contact with
the air.Thus it
seeks the lowest surface area in contact with air. The lowest
surface area shape depends on the shape of the frame.
This experiment displays two effects, Concentration Gradients
and Temperature Gradients that combine with gravity to
produce the periodic motion you see. Buoyancy pushes the thimble
up.Buoyancy is why
you float in water, but buoyancy changes with temperature and
solute concentration. The solute here is salt.
As the thimble is heated near the bottom of the cylinder, the
bubble of air we left in the thimble expands, pushing out some
increases the buoyancy and causes the thimble to rise.
As the thimble rises, it cools; the air shrinks, and pulls in
decreases the buoyancy of the thimble and causes it to sink back
to the bottom where the process is repeated.
In this experiment we use the pepper as a tracer to show
how the water is affected by the addition of a
surfactant, dish soap.
A surfactant is an additive that affects surface
This happened because the surface tension of the water
decreases, near the surfactant. Water molecules then
move with greater freedom into the area of higher
surface tension.The water then carries the pepper with it.
These beads are made out of a water absorbing polymer that share
similar material properties of water. The refractive index of
the bead is exactly the same as that of water, and causes for
light to go straight through it without getting detracted at an
The gray fluid in the Petri dish is made of aluminum
flakes in silica oil.
The aluminum flakes are just tracers; they show the
motion of the fluid.
The patterns you can see are the boundaries between
different convection cells.
As the fluid on the bottom is heated it rises,
displacing cooler fluid above which sinks down along
either side of the rising fluid.This kind of circulation is always occurring when
you are heating a fluid; however it is very difficult to
see without the tracer.
The Taylor cell has a rotating inner cylinder that moves the
fluid in circles.
These particles feel like they are on a merry-go-round, but the
low speed of the inner cylinder keeps the particles moving in
When the inner cylinder is spun faster the particles are thrown
out towards the side of the wall.They push the particles that are near the wall out of the
particles are sucked back in towards the cylinder and the
process is repeated.
They appear in bands because of the flat shape of the particles.
When moving towards you, they only look like a line, causing the
dark area. However, when being pushed against the walls of the
cylinder, they turn flat towards you, reflecting the light and
appearing a shiny silver color.
Water molecules have strong forces between one another, and have
very weak forces with air molecules. So, at the top of the glass
of water, the water molecules are much more attracted to the
water below them than the air above them. These strong forces at
the top of the water create surface tension, which is
responsible for making the paperclip float. Since the paper clip
does not weigh much, the surface tension is strong enough to
hold it up.
When soap is added to the water, the surface tension becomes
much weaker. This is because soap molecules interfere with the
water molecules' attractive forces by getting between the water
molecules. Once the water molecules' attractive forces between
neighboring molecules are weakened, the surface tension is not
strong enough to support the weight of the paperclip, so it
A fluidized bed is a column of small solid particles supported
by a grate that allows a fluid to pass through the bed. The
effect of air through the sand makes the sand act as a fluid. Our bed has sand-like particles fluidized by
common household example of a fluidized bed is a hot-air popcorn
heated air, suspends the particles which are the popcorn
Some applications of fluidized beds are:
Used in coal combustion to reduce costs and lower the emission
You saw how the softball floated on top of the sand.Farmers harvest potatos by scooping all the dirt and
dumping it on a fluidized bed.The potatoes float to the surface and are separated off.
Heated particles are suspended in a fluidization gas, and
provide heat and massage to the legs of horses.
When the dish rotates the ink moves in a circular path, provided
the motion is slow and the ink does not diffuse very quickly.
The fluid is purely viscous and not elastic and so it has no
“memory”. When you counter rotate the dish the ink simply
travels on the same circular path in the reverse direction. Thus
you can return the ink to its original placement. It is
important to move slowly when rotating the dish or you will
create disturbances or turbulence that distorts the line.
The composition of micelle consists of an excess of surfactant
molecules in a solution, forming an aggregate that encapsulates
a substance with the opposite polarity of its solvent, similar
in structure to a basic cellular membrane. The surfactant
molecules are composed of a hydrophilic (water loving) head and
a hydrophobic (water fearing) tail. This is what happens when
you clean yourself with soap.
Both vials contain the same amount of dye, but the excess soap
in the second vial causes micelles to form, and the dye to be
dispersed through the water.
The law of conservation of energy states that energy can neither
be created nor destroyed.
Heat must be removed from the cream by using liquid nitrogen.Nitrogen is only a liquid at temperatures below -320 °F.
The heat of vaporization is the amount of heat it takes to turn
a liquid into a gas.For Nitrogen is this value is 200 Joules/gram.Although Nitrogen is not a liquid at room temperature it
requires energy to vaporize.It gets that energy from the cream.This causes the cream to freeze instantly.Because it freezes so quickly, ice crystals do not have
time to form.This
makes the ice cream super smooth and tasty.
1 cup of heavy cream1 cup of half and half
½ cup of sugar½ tablespoon of vanilla extract
¾ cup of chocolate syrup
Mix the ingredients in a metal bowl.Metal must be used because nitrogen can freeze plastic,
and the slightest bump will make the fragile plastic shatter.
Hold on to the bowl with an insulated glove while you spray
liquid nitrogen into the bowl.