Science 200 – Blog #4 – Buoyancy and Floating Objects

“Why does a lump of clay sink in water, but float when it is a different shape?”

A lump of clay sinks in water because the density of the clay is greater than the density of the water. Greater density means that the particles making up the clay are packed closer togerther than the water molecules making up the water. The gravity is pushing down on the clay for it to sink.

As you can tell, clay sinks once put in water

But clay wouldn't sink if we made it in a shape like a boat

It would float because there is air in the inside of the boat. The air and clay displaces water and the average density of both air and clay is less than the water

110511 science experiment

Question

Does temperature affect the viscosity of oil? If so,how? How can this change be measured?

Materials

-60mL of oil

-graduated cylinder

-timer

-cup woth hole on the bottom

-beaker

-stand(?)

-thermometer

-box with full of ice and water

and....

-us!

During the experiment...

In this experiment we tested how the temperature of the vegetable oil affect the viscosity of the oil. We made the oil into 3types, 20 degrees, 9 degrees, and 52degrees. we have about 60mL of vegetable oil in the graduated cylinder, and we pour all of them into the plastic cup with the hole on the bottom. Then we measured the time that the oil fall into the beaker, when the oil reaches to 50mL, we stopped. when the oil's temperature was 9 degrees, the flow rate was low and when the oil's temperature were 52 degrees, the flow rate was high. So if the oil's temperature is low, it's flowrate is slow, and if the oil's temperature is high, the flow rate is fast.

*Flowrate=volume/time

110509,110510 Class #4

Matter=anything that has mass and takes up space (volume)


Volume=measure of how much space an object takes up
(common measurements-cm³,m³,km³,mL,L)


How to measure?
-regular shaped object (rectangle)
*use a formula = volume= length x width x height


-liquid
*use glassware....graduated cylinder!! (we have to look at meniscus)



-irregular shaped object
*use the principle of displacement
volume of the object=(Volume of object + water)-volume of original water


Mass=a measure of how much matter an object contains
(common measurement=kg,g,ton,mg)
*mass never change!!!
How to find it??-->scale


Weight=is a direct measurement of the force(full) of gravity on an object
(common measurement=Newton (N))
How to find??-->Force of gravity=weight=mass X g
*gravity of Earth=g=9.81m/s²


*****1N=1(kg x meter) /s²


Density=mass per unit volume, how much mass something has compared to its volume
How to find??-->use a formula - density=mass/volume
units:kg/cm³, g/m³, g/mL, kg/L, g/cm³, kg/m³...


Buoyancy=is a force=is the upward force on an object in a fluid

common measurment-Newtons

How to Find?-Archimedes Principle 
*The weight of the liquid that an object displaces when placed in a liquid is equal to the buoyant force (Fb)
-Floating or submersed objects

Fb=Density of liquid x Volume of liquid x g

ex1)Force of Buoyancy (of eraser)

       D=m/V

       m=DV

       m=(1.00g/mL)x7mL
          =7g

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Fg=m x g
    =0.007kg x 9.81m/s²
   =0.0687 N
   =Force of Buoyant

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Fg of eraser=mg
                  =0.008kg x 9.81m/s²
                  =0.785 N     

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Positive Buoyancy the tendency of an object to rise in a fluid because the object weighs less than the fluid it displaces

Negative Buoyancy the tendency of an object to sink in a fluid because the object weighs more than the fluid it displaces

Neutral Buoyancy the tendency of an object to remain level in a fluid because the object weighs the same as the fluid it displaces

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Why things FLOAT??


DENSITY!!

things that are less dense floats on the things that are more dense

* more dense=more force of buoyancy
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*1000mL=L
 1000cm³≠m³
*mL=cm³
 L≠m³

110427 Class #3

1.In terms of shape and volume, compare solids, liquids and gases.

shape

solid:fixed

Liquid:not fixed

Gas:not fixed

Volume

solid:fixed

liquid:fixed

gas:not fixed

2.Using the particle theory, explain why solids do not flow.

They(solid particles) don't have much energy, so they can't move freely, just vibrating at same place. So because they are just vibrating, they are packed tightly. 

3.The study of airflow (air moving around objects) is extremely important in both competitive sports and in commercial transportation.  Suggest several reasons for why this is the case.

For some of the competitive sports, 1 second makes their score really different. So to make a second less in their score, they have to go fast in some way, so airflow is really affecting their score, so it is extremely important. 

4.a)Compare the viscosity and flow rate of honey versus water.

hoeny=high viscosity=low flow rate

water=low viscosity=high flow rate

Class#2 Aerodynamic and Hydrodynamic Systems

Word Definition
Aerodynamic- air affects the movement of a solid things


*Japanese bullet trains wii be a perfect example of an aerodynamic object

  Hydrodynamic- something that affects the movement of water around an object


*Torpedos are shaped hydrodynamically to be able to move fast under water


Laminar Flow- when a flow of water is in a straight or close to being straight
example- a deep river without any obstacles underwater has a laminar flow

Turbulent Flow- a flow of water in an irregular way produced by rapids, eddies, or whirlpools
example- a steep river with many obstacles such as rocks has a turbulent flow

Laminar rivers flow smoothly when turbulent rivers flow in somewhat kind of an odd way

Drag- something that concerns with the speed of water(liquid) that resists agianst its flow
Streamlined- an objects is said to be steamlined when an object is made in a shape that helps reduce the resistence of water as much as possible

sharks move smoothly underwater especially that creates a laminar flow

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How a type of technology is built to minimize air resistence??0.0

Type of technology built to minimize air resistence are parachutes. They are built in a circular way to minimize air resistence.

110422 Class #1

Word Definitions

1) Fluid:Substances that flow (liquid & gas)

2) Particle Theory:a theory used to explain matter and heat transfer which suggests that all      mater is made up of tiny particles too small to be seen. These particles are constantly in motion because they have energy. The more energy they have the faster they move.


3 POINTS OF PARTICLE THEORY

• All matter is composed of particles.
• Particles are in constant motion.
• There are forces of attraction among particles. 

3) Flow Rate: the speed that a fluid moves in a given amount of time

4) Viscosity:the physical property of a liquid that limits its ability to flow
 ------>high viscosity = low flow rate
           low viscosity = high flow rate

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Non-Newtonian

Non newtonian fluid's viscosity is changeable based on given pressure.
ex)Oobleck, Flubber,Ketchup,Silly Putty, Chilled Caramel topping ...
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Photos!!
We mixed water, potato starch and some color to make a non-newtonian fluid!!
It is like solid, but if we grab it, it changes like liquid!!

by.municorn9702