Science
The observation, identification, description, experimental investigation, and theoretical explanation of phenomena is all part of science. Nothing is immune to the scientific process: from charm quarks that haven't existed naturally since the beginning of time to Pluto, recently demoted from planet to dwarf planet. Questions on knowledge about the material and physical aspects of our world are asked and answered here.
Asked by Ciara Parker in Sound Waves, Science
Is silence a sound?
Asked in Science, Atomic Mass
What is gold's mass number?

The only stable, and only naturally-occurring isotope of gold
has mass number of 197. This is the number of protons and neutrons
in each nucleus.
Gold's atomic number is 79. This is the number of protons found
in each gold atom. This determines its place in the periodic table,
and its chemical properties: it is the defining property of
gold.
A nucleus with a different number of neutrons and the same 79
protons would be a different isotope with a different mass number;
a nucleus with a different number of protons would not be gold, but
some other element.
Asked in Science, Earth Sciences
What is the rock cycle song?

SEDIMENTARY rock Has been formed in layers Often found near
water sources With fossils from decayers
Then there's IGNEOUS rock Here since Earth was born Molten Lava,
cooled and hardened That's how it is formed
These two types of rocks Can also be transformed With pressure,
heat and chemicals METAMORPHIC they'll become
(sung to the tune of row row row your boat)
(=**=) (<cat lol)
Asked in Science, Chemistry, Acids and Bases
What are some examples of chemical and physical changes?

Physical Changes
Change of state (such as from solid to liquid or from gas to
liquid)
Specific examples of state change include water freezing,
alcohol evaporating and dry ice (solid carbon dioxide)
subliming
Absorption of water into a towel
Crumpling a piece of paper
Pulling copper into a thin wire - a change of shape, but not a
change of composition
Cutting a material such as wood
Tearing a piece of tin foil
Breaking glass
Deflating a basketball
Mixing different solids (such as solid sulfur and iron
filings)
Inflating a volleyball
Cloud forming in the sky
Chemical changes
Burning a log of wood
Mixing an acid with a base, producing water and a salt.
Photosynthesis - a process in which carbon dioxide and water
are changed into sugars by plants.
Cracking heavy hydrocarbons to create lighter hydrocarbons
(part of the process of refining oil).
Cooking examples: popcorn, cake, pancakes, and eggs
Oxidation examples: rust or tarnishing
Combustion
Mixing chemicals
Rotting of fruit
Cooking rice
Explosion of fireworks
Tarnishing silver
Lighting a match
Chewing/digesting food
Rusting nail
Burning gas in a stove
Oxidizing food for energy
Roasting a marshmallow
Adding food coloring to icing
Frying an egg
Burning a magnesium strip
The following can indicate that a chemical change took place,
although this evidence is not conclusive:
Change of color (for example, silver to reddish-brown when iron
rusts)
Change in temperature or energy, such as the production
(exothermic) or loss (endothermic) of heat
Change of form (for example, burning paper)
Light, heat, or sound is given off
Formation of gases, often appearing as bubbles
Formation of precipitate (insoluble particles)
The decomposition of organic matter (for example, rotting
food)
Asked in History of Science, Science, Superstitions
What superstitious beliefs have a scientific basis?

Superstitious belief, by definition, have no scientific basis.
Science requires that ideas are tested in a way that is
repeatable and falsifiable. Falsifiable means that
there must be a way that the test shows that a stated belief is
not true, while most superstitions rely on metaphysical
entities or powers that are so vague they can not be
dis-proven.
Here are some examples of superstitions, and where they may have
come from.
Breaking a mirror is seen as seven years of bad luck from a
historical root.
Back in the medieval times mirrors were very expensive. And if
you broke one, it was reguarly someone important, such as the lord
of the kingdom of the king or a high-ranking nobleman. And if you
broke it, it was common that if they were un-forgiving, they would
put you in jail, possibly for seven years.
Walking under a ladder is seen as bad luck
Typically a ladder means someone at the top of the ladder and
that person can easily drop things - onto your head. So it really
is a bad idea to walk under one.
Never sweep the floor at night or you'll sweep sorrow into your
life.
You may not be able to see where you're sweeping and fall and
get injured.
Chase away any owls outside your window; they are a harbinger
of death.
They may erode your windowsill by pecking on it, and when you
lean on it, it may break and you may fall.
Never start or buy anything on a Friday.
Since Friday is the last business day, you or your order will
probably not be active on the weekend.
Cut your hair on a full moon and it will grow back faster.
Well, if you cut your hair at a barber's shop, and you can see
the moon, the barber will probably bee in a hurry to leave and so
will give you a shorter haircut.
Crickets in your 苹果彩票网登录 are good luck (not in my 苹果彩票网登录 and
definitely not for the nasty crickets!)
They tell the temperature.
Killing a spider is bad luck.
In addition to reducing local disease-carrying insects, spiders
provide humans with other medical benefits. Spider venom is used in
neurological research and may prevent permanent brain damage in
stroke victims. The silk produced by spiders is used in many
optical devices including laboratory instruments.
Ivy growing on a house protects the inhabitants from witchcraft
and evil.
Evil may mistake it for poison ivy and stay away.
Friday the 13th is unlucky
The Templars were all arrested (and most were tortured and
executed) one Friday the 13th!
Actors believe that using real money as a prop is bad luck.
This is probably rooted in the fact that leaving real money on
stage or in your costume means that there is a good chance that the
prop will disappear before the next performance.
Opening an umbrella in the house is bad luck.
Like walking under a ladder, this is just a hazard; you could
hit someone or break something.
Bad luck comes in threes.
This is sometimes expressed in notable deaths occurring in
threes. In fact, this is a well-known psychological bias known as
"confirmation effect"; when two events occur, people naturally
anticipate a third (two things don't form a pattern, but three do).
When the expectation is satisfied, it "proves" the adage. Of
course, if it is not, then the pattern is not recognized.
Asked in Science, Urinary System
What are the tubes called that carry urine away from the kidneys to the urinary bladder?

As I believe has already been stated the Ureters, which are also the source of blockages from kidney stones. Not where they come from that is but where stones large enough usually 5 mm can cause blockages. 2 and 3 even 4 mm stones csn take up to 45 days to pass but usually do.
The danger is if stones are present in both Ureters and are causing blockages then the urine can back up and seep into your abdomen and cause infection throughout, this is called sepsis and is life threatening which can kill you in a matter of hours.
They usually implant a stint bypassing the Ureter to avoid such an incident, the good news is your body was designed with redundancies. You only need 1/3 of 1 kidney to sustain bodily function.
Asked in Science, Cooking 苹果彩票平台
Why is the pan handle made of plastic?

The first and last answers simply are not correct, nor do they
answer your question. The second, middle question is much better,
but it does not fully answer your question either.
If a metal pan with a plastic handle is put in the oven at,
let's say, 350 deg., then the temperature of the entire pan, metal
and plastic, will eventually reach 350 deg. It is not true that the
plastic won't get hot, actually it should heat up faster than the
metal.
There are two properties in consideration: heat capacity and
thermal conductivity. Metals in general have large heat capacities.
One can think about the amount of heat a substance can store per
unit mass, called the "Specific Heat," or one can consider the
amount of heat a substance can store per unit volume. In the case
of a pan and handle, it makes more sense to look at the question in
terms of the heat stored per volume.
Most people know from everyday experience that metals
stay hot longer than non-metals like wood and plastic. That is
because metals have a much larger heat capacity per volume than
most non-metals; that is they hold more heat.
What about thermal conductivity? In this case, we only need to
consider the thermal conductivity of air.
Heat flows FROM a hotter object TO a cooler object. If a pan w/
plastic handle is put in a 350 deg. oven and allowed to heat up
completely, when it is taken out the oven the pan and handle are at
350 deg. We only need to consider the heat transfer from the metal
to the air and from the plastic to the air. Since the cooler
material is the air, all that matters is the thermal
conductivity of the air. You can look up thermal
conductivities in a table, but air, and all gasses, have much lower
thermal conductivities than almost any solid, and it is certainly
lower than the pan and Bakelite® (the pan's handle). Since the
handle does not contain as much heat as the pan, it will cool down
to a touchable temperature faster.
The same applies if the pan is placed on a burner. The handle
will take longer to heat up than the metal because 1) the metal is
directly over the flame, and 2) the metal has a higher thermal
conductivity than the plastic meaning that a lot more of the heat
from the burner will be absorbed by the metal.
Answer
The reason the pan Handle is made of plastic is because Plastic
is not a conductor of heat so it won't get hot. If the handle was
metal it would get very hot because it is a conductor of heat.
Answer
Frying pans have plastic handles because plastic is a terrible
conductor of heat that is coming from a stove. Therefore the handle
is cool even when the metal of the frying pan is hot, when you need
to lift it, or perhaps something else.
Answer
Safety. Plastic will not conduct either heat or electricity, so
in order you can safely handle pots and pans, plastic is used for
those reasons.
Conductivity of air plays practically no role in this. If the
pan heats up air in contact, that air is immediately removed by
convection and replaced by cool air.
Asked in Science, Chemistry
10 examples of physical change and chemical change?

Physical Change:
*Milo dissolves into hot milk
*A plate is dropped and shatters
*Grass in mowed
*Metal Knife is sharpened
*Breakfast Cereal goes soggy
Chemical Change:
*Wood burns to form black charcoal
* A green tomato ripens and turns red
* Fireworks explode to form colourful light and loud sounds
* Vegetables scraps in the compost bin decompose to form rich
soil
* An egg is cooked to become a white and yellow solid
Asked in Science, Ingredient Substitutions, Baking Soda (sodium bicarbonate)
What is an alternative to bicarbonate soda?

Depends on what reciepe you are using and what the purpose is: I
often use yeast but in some recipes depending on the fluffiness of
the cake I will sometimes use baking soda. A friend of mine uses
"fizzy water" (carbonated water) as an alternative.
Yeast is only used in bread related recipes, whereas bicarb can
be used n cakes
~
Baking Soda in a recipe is to help with 'spreadability of the
cookie or cake. You don't use it in pancakes so you want the batter
to 'stay put'. In a cookie, you want it to spread out a bit, in the
cake, you want it to fill in the space of the pan.
Baking Soda and Baking Powder CAN be used for each other in a
subbing situation. They are both considered leavening agents. In
choosing to substitute one for the other you have to know the ratio
AND the fact the flavor WILL be DIFFERENT.
1 TSP of Baking Soda needs 3 TSP of Baking Powder. OMIT all
SALT.
Reverse it to use soda instead of baking powder.
You can also use 2 tsp soda and 1 tsp cream of tarter to create
BAKING POWDER. Again, omit the salt from the recipe.
AGAIN, any substitutions of ingredients, expect flavor change to
happen.
Asked in Science, Physics, Chemistry, Chemical Bonding
Why does water have a high and specific heat capacity?

First, we need to know a little bit about water. Water is a
polar molecule because oxygen bears
partial negative charge and hydrogen bears
partial positive charge. This results in extensive
hydrogen bonding in water molecules between
slightly negative oxygens and slightly positive hydrogens. Second,
we need to remember that temperature is another way of saying the
average kinetic energy of particles - the higher the
temperature, the faster they move, in the case of gases and
liquids, or vibrate, in the case of solids. Third, heat capacity is
the ability of matter to absorb thermal energy. One calorie is
defined as the amount required to heat a gram of water one degree
Centigrade. That same calorie will heat a gram of gold 33
degrees.
Water's specific heat is defined as 1. The specific heat of gold
is therefore .03. Water has a high specific heat because there are
quite a few ways water can store heat. 1. Moving along three axes
2. Rotating the "V" shaped molecule in three different directions
3. Hydrogen atoms vibrating back and forth like a tuning fork 4.
Hydrogen atoms vibrating up and down along their H-O axis.
Finally, the heat of fusion of water is 80 calories per gram,
and the heat of vaporization for water is 540 calories. So ice can
absorb 80 times as much heat while melting as the same mass of
water. Water absorbs 540 times as much heat while turning into
water vapor as the same mass of water absorbs. Both phase changes
occur at constant temperature, 0 Centigrade and 100 Centigrade
respectively. Look up phase change graph for water to see the
interesting line.
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