A middle school student so how can I explain to an elementary kid on what determines wheter an object floats?
959807
You must show not tell. Take a bowl filled to the top with water and put it on a plate to catch overflow. The put objects in the water and compare the overflow for sinking and floating objects of the same size. If you have a scale weigh the objects and the water if not just hold them and judge weight. Then explain density.
810641
Use Archimedes's buoyancy principal.  The weight outside represents the response of mass to the Earth's gravity.  The weight in water represents the displaced water's weight.  Use the ratio to get the answer.  HINT: if you convert to mass, the answer almost gives itself away.\nThe displaced water has a well known density.  That density will give the volume of the both the displaced water and the object displacing it.
754995
Nicole I think that to understand what is to be done here I suggest to assume that a coordinate system be attached to one of the objects. I-don’t-remember-who says, but << any reference system at rest or moving with linear constant speed has no privilege with others the like>>.\n(x) m2=4kg is reference system #2, where v2=0, and m1=2kg is moving with speed v=8+12=20 ms, impact by m1 on m2 M1=m1*v=40kg*m/s\n(y) m1=2kg is reference system #1, where v1=0, and m2=4kg is moving with speed v=8+12=20 ms, impact by m2 on m1 M2=m2*v=80kg*m/s, so R=40/80=0.5
255989
A stationary body submerged in a liquid is effected by two forces, gravity and buoyancy. Gravity acts at the center of mass and it is always directed straight down. On a rigid body, the center of gravity can be considered stationary in reference to the body. Buoyancy, on the other hand, acts at the center of buoyancy, and the center of buoyancy moves as the body tilts and rolls. The size of the gravity force is;\n\nFg = Mass * Gravity\nThe size of the buoyancy force is proportional to the volume of liquid that it displaces, the force of gravity and the density of the liquid.\n\nFb = (Volume * LiquidDensity) * gravity\nWhen an object is stable in the liquid, the gravity force and the buoyancy force cancel each other out. This means that the boat is displacing an amount of liquid that weight as much as the boat does itself.\n\nFg = Fb
152879
No, it will not.  The other answers to this question are on the right track, in that they point out that an object's density is the key thing in most situations, since if it is less dense than the fluid it is in, it will displace fluid equal to its weight before it is completely submerged, and hence float.\n\nBut in *this* problem, we are told from the outset that there is not enough water to be displaced.  Therefore, the object will displace all the water, all 1 lb. of it, and still not have displaced enough water to equal its weight.  Therefore, it will rest on the bottom, i.e. not float.
257654
Say the anchor weighs 15 pounds in air and displaces 2 pounds of water.\nBefore the drop, the boat displaces its weight plus the 15 lb weight in air of the anchor. This is the maximum displacement situation, so the water is at maximum height.\nAfter the drop, if the anchor hits bottom, the boat displaces its weight only and the anchor displaces 2 lb of water, the minimum displacement situation, so the water is at minimum height.\nAfter the drop, if the anchor doesn't reach the bottom, the boat displaces its weight plus the 13 lb weight in water of the anchor. The anchor displaces 2 lb water. The total displacement is the same as the maximum displacement situation, so the water is at maximum height.
298529
If you know the density of the material, you can measure it's volume.  D = M / V.  Therefore, the mass equals the density of the object times the volume.  The weight of the material is its mass times gravity.
903478
fat content\n\n\nthe fattier it is, the more it'll float
229380
It will weigh things that are suspended in air or water. It was invented by Newton.
984991
Density = mass / volume\nTo find the volume of an irregular object submerge it in water the amount the water rises is the volume of the object.
218971
Any object will float as long as it displaces a volume of liquid that is more massive than itself. Take the aluminum boat and fold it into a block of aluminum and it sinks. But due to the shape of the boat, the mass of the aluminum,plus you, and your fishing gear, is still less than the volume of water pushed aside by the hull of the boat. So, you float.
618509
fill water balloons with different amounts of water and drop them at the same height to see if they fall differently.  =)
1075806
I assume that you mean that the object is perpendicular to the velocity of the wind.\n\nConsider a flat plate, area A, against which a wind of speed v is blowing.  The air has a density of p.  All measurements are made in a consistent unit system of course.\n\nIn one second a mass of air will be brought to rest, this mass is given by A x p x v\n\nThe momentum change of this air is therefore A x p x v²\n\nwhich gives the force on the flat plate.  Your object will also have a drag coefficient (Cd) the more streamlined the object is the lower it's drag.  So the total force becomes:\n\nA x Cd x p x v²\n\nYou will have to look up the drag coefficient for your object in a text.
657765
1. the object is pushed up by the weight of its equivalent volume of water, 4-3.2=0.8l\nSo the object's density is equal to its mass divided by its volume:\n4kg/0.8l=4kg/0.0008m3=40,000kg/8m3=5000kg/m3\n\n2. the force decreases with the square of distance, so it will be 3^2=9 times smaller, which is 6N.
191749
i agree that it's probably lead.  lead is very dense, so your things should feel very heavy for their size.  you can verify this by a couple methods:\n\n1.  get an accurate scale and measure the weight of a piece.  then get a graduated cylinder from your school and fill it partway with water.  dunk the same piece of the metal into the water and see how much the volume changes.  divide the weight by the volume to get the density.  compare this to the density of lead which is 11340 kg/m^3 or 11.34 grams/mL.\n\n2.  if you have a voltmeter, do the following:\n - get a tub of water and dissolve some salt in it\n - cut out a strip of aluminum foil and immerse one end in the water\n - take your mystery metal and immerse one end in the water\n - make sure the two metals aren't touching\n - connect one probe of the voltmeter to the aluminum, and the other probe to the metal.\n - aluminum has an electrode potential of 0.13 V and aluminum has an electrode potential of 1.66 V, so if lead is the metal then the voltmeter should read 1.66 - 0.13 = 1.53 V.\n\nsounds like you are going to have some fun!\n\nalso, lead is toxic so wear gloves and wash your hands after you handle it.
726772
Its a trick Q...\n1. If floating on Surface, then 0 (since ur ballon is massless, although theoretically, nothing is massless..)\n2. If forced to stay inside water, then it would be equal to the weight of water displaced (i think ur Q is phrased wrongly, it is 1000cm3 displaced water ( or else the answer depends on the volume of the balloon).. Or simply, it is equal to the force used to keep the balloon inside water.
905607
make a little "boat" that you can add weights to and float it in the different liquids.  Gradually add weight to the boat in each liquid to see how much it can hold before it sinks.  The more weight the boat can hold, the greater the density of the liquid!\n\nThis is basically a poor-man's hydrometer.