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by Ron Kurtus

A total of 94 comments and questions have been sent in. They are listed according to date.

List of next 10 letters

Country

Floating Salt water and floating USA

Pressure Squeezing a sealed plastic bottle USA

Floating Why are lighter molecule in high altitute? USA

Pressure Velocity of water in a pipe Canada

Fluids Force in square container TANZANIA

Floating What solids will float on liquid mercury? Canada

Floating Egg covered in foil floats USA

Floating Expansion of balloons USA

Floating Needs to make a submarine USA

Fluids Volume of an egg USA

Next 10

First 10 letters

Salt water and floating

Topic: Floating

Question

April 18, 2005

Does the amount of salt in sea water effect how objects float in it?
P.S. I need this by 4-19-05
thank you Pattilynne Webb

Pattilynne - USA

6693

Salt make the water denser, such that objects will float easier in the salt water. The Great Salt Lake has almost the most salt anywhere. A person can float real well in that water.

Squeezing a sealed plastic bottle

Topic: Pressure

Question

April 15, 2005

Squeezing the sides of a sealed plastic bottle filled with a liquid
a.decreases the volume of the fluid
b.increases the pressure of the fluid
c.increases the volume of the fluid
d.decreases the pressure of the fluid?????

debbie - USA

6674

The volume of the fluid will not change much, but the pressure increases. If there is any air in the bottle, that will decrease in volume due to the squeezing.

Why are lighter molecule in high altitute?

Topic: Floating

Question

April 7, 2005

What are the physical bases of the earth's climate and weather?

Explain why the compostion of the earth's atmosphere at an altitude of 759lm is He, H, and O, instead of the heavier molecules such as O2 and N2.

gale - USA

6582

Lighter molecule move up, while heavy ones are pulled down similar why lighter object float up to the top in water, while heavy objects sink.

Velocity of water in a pipe

Topic: Pressure

Question

April 4, 2005

Hi.

I have a physics problem which seems impossible; A horizontal pipe 10cm in dia.
has a smooth reduction to 5 cm in dia. if the pressure in the large pipe is 8x10(4) and the pressure in the smaller pipe is 6x10(4), at what rate does the water flow through both sections?

I am quite confused b/there is no velocity given to be able to calculate flow rate,but pressure is given, but I do not know what to do with it.

Joanna

6536

If you had can of water 10 cm deep and at 5 cm, you stuck a pinhole, the water would squirt out due to the pressure of the 5cm of water above the hole. So there you have the pressure and instead of a pinhole, it is a 5cm hole.

I hope that is enough to solve the problem.

Force in square container

Topic: Fluids

Question

March 17, 2005

I AM A STUDENT IN ADVANCED SECONDARY SCHOOL IN TANZANIA.
I HAVE A PROBLEM IN ANALYSIS OF FORCES DUE TO FLUID ACTING IN A SQUARE AND ROUND CONTAINER.

THANK YOU

JONATHAN - TANZANIA

6373

The force in a fluid should not be dependent on the shape of the container. Teh force should be equal in all directions.

What solids will float on liquid mercury?

Topic: Floating

Question

March 6, 2005

Hi I need to know this: "What solids will float on liquid mercury?"
- Please email me on March.7, 2005, Thanks so much!

6239

Mercury is heavy and dense. Look at the Periodic Table at:
http://www.school-for-champions.com/science/chemperiodic2.htm

You will see metals that are lighter that mercury (Hg) such as iron and gold that should float on the substance.

Egg covered in foil floats

Topic: Floating

Question

February 26, 2005

Why will an egg covered in foil or cling wrap float in water, when a normal egg sinks?

- USA

6127

I had never heard of that, so I had to try it myself. Amazing! I know there are experiments where you can make an egg float by adding salt to the water to change the density, but this is different.

The only thing I can thing of is that the egg shell is very porous and quickly absorbs water. When the egg is wrapped in foil, the shell can't add the extra weight of the water, so it won't sink.

Note that old or spoiled eggs will float, but fresh ones will sink.

Expansion of balloons

Topic: Floating

Question

January 30, 2005

If you fill ballons at 22 degrees C, with equal volumes of oxygen, helium,
argon and air to make the ballons the same size then heat the ballons, will they all expand the same amount? If not, why?

- USA

5778

The pressure inside each balloon would be the same, because they are the same size, but the density of each gas would be different, due to their different weights.

According to Charles' Law, the expansion would be at the same rate, assuming they were ideal or perfect gases. Actually, there is a difference.

Needs to make a submarine

Topic: Floating

Question

January 17, 2005

i have a science project and it is to make a submarine out of what ever but it must sink, float, and then sink again with out me touching it, or vis vera. Is there such a way to do this???????

please i need help now !!!!!!!! i must turn this in by wed. 1/19/05

lori - USA

5648

See this page for an easy experiment that will be like a submarine:

http://www.onr.navy.mil/focus/blowballast/resources/bouancy2.htm

Volume of an egg

Topic: Fluids

Question

January 15, 2005

Can you please assist me in measuring water volumes. I need to contruct an egg shaped container that will hold a wter volume of 40 gals. Can you please assist me with diminions?
Don Druse
Founder and President of North American Inshore Sportsmen

Don - USA

5621

It is extremely difficult to calculate the dimensions of an egg shape. Eggs have all sorts of different proportions.

If it was a sphere that held 40 gallons of water, it would be 26 inches in diameter.

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