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Science Experiments
Experiments often conducted by students to test different scientific theories and hypotheses
11,111 Questions
Why is it so important to control variables in an experiment?
You need to control variables in an experiment so as to make sure that only the variable you are testing and changing is the one affecting the results of your experiment. For example, in an experiment to find the effect of light intensity on the rate of photosynthesis of plant, you'll change light by putting a plant in sun and another in dark but you must not change carbon dioxide level for both plants so by that you have controlled other variables in the experiment(variables which must be the same always in the experiment).
What temperature differences occur from beginning to end in an explosion?
Well if you turn around three time and then say i like watermelons that is your answer
Any excess materials that are not used during a laboratory experiment may be poured down the drain?
No. Chemicals should be disposed of in a safe manner. Usually directions for disposal can be found on the box/tube/packet that the chemical came in. If none can be found, ask a professional (teacher, lab assistant, poison control expert) what is the proper disposal for a certain chemical. Excess materials poured down the drain may be poisonous to the environment or people, and can leak from the sewage system to our ground water and eventually to our food.
Which fluid force opposes lift?
Answer The essence of your question is very complicated and concerns fluid mechanics but I will simplify it as much as possible. In short, the force that opposes lift is weight (the gravitational force acting on an object's mass). If lift is greater than weight leaving all other variables such as air resistance are left the same the object is ascend. If weight is greater than lift the object will descend if already in the air or never take off if still on the ground. This question is at the heart of why planes fly. The leading edge of the wing causes the air on top to travel than the air on the bottom. Bernoulli's principle says as the speed of a fluid increases the pressure of the fluid decreases. As a result, the air on top of the wing has a lower pressure than the air on the bottom. Fluid go from high to low pressure. The air on the bottom of the wing exerts a force upward and thus the plane rises. It is important to know the other two force crucial in the flying of plane. They are thrust and drag. Thrust is the reactionary force to the force that push air out of a jet engine or from propellers. Drag is the force of air resistance and it is proportional to the velocity of the object. In other words, as the object goes faster the force trying to slow it down increases as well. This continues until the object reaches terminal velocity. Terminal velocity is the point at which the force acting on an object and the frictional force become equal in magnitude and opposite in direction. As a result, the net force acting on the object is zero and the object stops accelerating and falls at a constant rate from that point on.
What is the abstract for egg in bottle experiment?
First, the science behind a hard-boiled egg: Egg whites are made of water and proteins. Proteins are made of long chains of amino acids, but in an egg the chains are clumped tightly together in individual spheres. (These are called "globular proteins.") When the egg is heated, the proteins and water molecules begin to move faster. As they move and collide with each other, the individual protein chains start to "unravel," eventually bonding loosely with other protein chains, forming a network of protein with water trapped inside. The consistency has changed from runny egg white to a soft solid!
So how does this squishy-but-solid egg get mysteriously pushed inside the bottle? The answer is all about air pressure. When you first set the egg on the bottle, the air pressure inside the bottle matched the air pressure outside, so nothing happened. When you dropped the burning paper into the bottle, it caused the air inside to heat up and expand rapidly. That expanding air pushed the egg aside and escaped from the bottle; that's why you saw the egg vibrating. When the fire consumed all the oxygen inside the bottle, the flame went out and the remaining air in the bottle cooled down. Cool air takes up less space, exerting less pressure inside the bottle. (The egg acted as a seal to prevent outside air from getting in to fill the extra space.) The result was an unbalanced force-the force of the air pushing on the egg from outside the bottle was greater than the force of the air pushing up on it from inside the bottle. Voila - the egg was pushed into the bottle!
How do you get the egg out again? You need to increase the pressure inside the bottle. Turn the bottle upside down and tilt it until the small end of the egg is sitting in the mouth. Now put your mouth close to the bottle and blow, forcing more air into the bottle and raising the pressure inside. When you take your mouth away, the egg should pop out.
What is a control group for a science fair project with stains and detergent?
a control group is a sample that is treated like the other experimental groups except that the independent variable isn't applied to it
What primary principle of experimental design did their experiment fail?
On March 23, 1989, the chemists Stanley Pons of the University of Utah and Martin Fleischmann of the University of Southampton announced to the world that they had achieved cold fusion. That is, with a solution of salts in a simple desktop apparatus, they had caused hydrogen atoms to 'fuse' or combine into helium atoms. This reaction had previously been achieved only in hydrogen-bomb blasts and in giant research projects lasting many decades and costing many billions of dollars.
The two chemists claimed that they had been able to measure the energy released by the fusion process in their simple setup. The scientific world was in an uproar, because if this were really true, cold fusion would be the greatest discovery in a thousand years -- a practically infinite source of cheap, safe energy.
However, no matter how hard they tried, no other scientists were able to get the same results. Pons and Fleischmann had dozens of excuses, but none of them were shown to have merit. Ultimately, both scientists resigned in disgrace.
REPLICATION
Any physics project based on zero gravity forces?
Create a unique gold-aluminum alloy, which can only be made in a zero gravity environment, and which has an amazing green color.
What types of gases does planet Earth have?
There would be numerous atmospheric gasses in varying concentrations including all the Noble Gasses.
The greatest being:
- Nitrogen (N2) - 78%
- Oxygen (O2) - 21%
- Water Vapor (H2O) - 0 to 4%
- Argon (Ar) - 0.93%
- Carbon Dioxide (CO2) - 0.04%
- Neon (Ne) - 0.0018%
- Helium (He) - 0.0005%
- Methane (CH4) - 0.00017%
- Hydrogen Gas (H2) - 0.00005%
- Nitrous Oxide (N2O or NOX) - 0.00003%
- Ozone (O3) 0.000004%
see:
http://www.physicalgeography.net/fundamentals/7a.html
Do compressed cylinders of medical oxygen contain ephedrine or any bronchial dilators?
They shouldn't. A person taking the oxygen could have an adverse reaction.
Why does a nail rust faster in warmer water than room temp?
I will assume you are referring to a normal iron or steel nail. Such a nail will tend to oxidize (rust) whenever there is oxygen present. Submerging a nail in water will not deprive it from a source of oxygen.
Generally speaking, water is a solution of H2O and a wide variety of chemical compounds that are in solution with it. Among these, and prominently so, are the gasses that comprise the atmosphere, including oxygen. This oxygen will readily combine with the iron in the nail to form rust. In fact, other compounds within the water may cause the reaction to occur more or less quickly than it would in the air.
It is incredible how much gas is dissolved within water. Imagine a large pot of tap water on the stove. As it heats, bubbles begin to form on the sides, then collect together and rise to the surface. These bubbles are not bubbles of steam (gaseous water) like many people think, but dissolved air being forced out of the water. There are a lot of bubbles. Imagine how much air you would have if you could collect all the bubbles.
Why the amount of DNA produced with pcr is expected to double with each cycle?
double stranded DNA into single stranded DNA meaning that 2 DNA strands can be produced
Can an object have a negative density?
No.
All matter has a positive mass (
Thus, any mass/volume calculations would also be positive.
Keep in mind that air near sea level has a density of between 1.2 and 1.3 kg/m3 depending on the temperature.
Some substances will have lower densities than air, for example:
The density of Helium at 1 ATM, 0°C is about 0.178 kg/m3
The density of hydrogen at 1 ATM 0°C is about 0.090 kg/m3
Thus, balloons filled with hydrogen or helium will float in air.
In space, the density is usually measured in particles / cubic meter, and is very low.
A perfect vacuum would have a density of 0.
What happens to a leaf if you put squares of aluminum foil on it for 5 plus days?
nothing happen in my experiment
Is a magnetic linear accelerator a good science project?
It looks like a nice project for up to about the third grade. After that you need to get a little more complex.
Why can beta particle not exist inside the nucleus?
because it is an electron which orbits the nucleus
What does a fulcrum looks like?
A fulcrum is any point in a lever where the lever pivots. They could be as simple as a nail through two pieces of wood, or as complex as those used in mining equipment such as loaders or trucks.
precise but unreliable.
How do you prepare ppm standard for aas?
To prepare AA (atomic absorption) standards, it is sometimes necessary to prepare double dilutions from the original standard bottle, but not always.
In order to obtain accurate results, it is very important to always do these two things: 1) Ensure that the standards being used are "NIST Traceable." The primary standards being used should have the phrase "NIST Traceable Standard for AAS," or "This AA Standard traceable to NIST." Or a phrase similar to these two.
NIST stands for National Institute for Standards Technology. It is a US federal governmental agency that works with industries to develop and apply technology, measurements, and standards. As it applies to your question, NIST maintains the most accurate and precise standards for calibration of AAS instrumentation. 2) If you plan to prepare multi-element standards, it is important to refer to the information that came with the AA primary standards you plan to use. Better is to purchase the needed multi-element standards in the first place, even if they contain a few elements in which you are not interested. This is because the soluble salt of one element that was used to prepare its primary standard may not be compatible with the soluble salt of another element in its primary standard. For example, let's say that you want to make an AA standard containing silver and copper, so you add the appropriate volumes of NIST-traceable copper chloride and silver nitrate standards. If someone prepared a standard this way, then it is likely that he will not even be able to calibrate the AA instrument for Ag, depending on the relative Ag and Cu concentrations. If the AA is calibrated for Ag, then the reported results will biased very high since AgCl is completely insoluble for AA purposes.
To prepare a standard from a primary standard bottle, simply use the equation:
V1·C1 = V2·C2 where V and C represent Volume and Concentration respectively. Thus, if you wish to make 1.00 L of a 2.00 ppm solution and the concentration of the primary AA standard is 100 ppm, then the only unknown term in the equation is V1, the volume of the primary standard needed. V2 is 1.00 L or 1000 mL, C2 is 2.00 ppm, and C1 is 100 ppm. Solving the equation for V1 = (1000 mL)(2.00 ppm)/(100 ppm) = 20 mL. Therefore, you need to add 20.0 mL of the primary standard to a 1000 mL volumetric flask and carefully add enough deionized water, shaking occasionally, so that the final volume is 1000 mL, not 1002 mL.
From a Bottle Of Soap Bubbles What is that stick that forms bubbles called?
It is called a bubble wand.
