8. We know that density of water is 1gm/cm cc RELATIVE DENSITY of a substance But how to prove this? Density of substance = Density of water at 4C Density of substance = 1gm/cm cube Density of substance =
10. Archimedes’ Principle Archimedes Principle states that when a body is partially or completely immersed in a fluid, it experiences an apparent loss in weight due to upthrustand this apparent loss in weight is equal to the weight of the fluid displaced by the immersed part of the body Upthrust means Buoyant force
11. What is BUOYANCY and UPTHRUST? What is BUOYANCY and UPTHRUST? Or upthrust
12. BOUYANT FORCE or UPTHRUST When a body is immersed partially or completely inside a fluid it experiences an upward force called the buoyant force
13. Buoyancy The property of the fluids to apply buoyant force is called BUOYANCY
17. Materials required for verifying Archimedes principle are: Verify Archimedes principle SPRING BALANCE STONE EUREKA CAN BEAKER
18. Verifying Archimedes’ principle Take an Eureka can and fill it up to its spout. Take a stone and suspend it with the hook of the spring balance.Note the weight of stone in air.Let it be w1. Now immerse the stone inside water in the Eureka can.the water overflows through the can.Collect this overflowing water in the beaker. Now also note the reading in the spring balance.Let it be w2
19. This w2 will be less than w1 due to upthrust provided by water.Apparent loss in weight due to upthrust will be (w1-w2) Measure the weight of water collected in the beaker , which in fact is the weight of water displaced by the stone . On comparing we will found that the loss in weight (w1-w2 )is equal to the weight of the water displaced by the stone.Hence the Archimedes’principle is verified. It states that when a body is partially or completely immersed in a fluid, it experiences an apparent loss in weight due to upthrust and thisapparent loss in weight is equal to the weight of the fluid displaced by the immersed part of the body
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21. Principle of Floatation A body floats in a liquid if the weight of the body is equal to the weight of the liquid displaced by it
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26. Where will they “float?” Object A: density= 0.8 g/cc Object B:density= 0.95 g/cc Object C:density= 1.1 g/cc oil density= 0.9 g/cc Object D:density= 1.3 g/cc Object E:density= 4.0 g/cc fresh water density= 1.0 g/cc salt water density= 1.2 g/cc
29. A ship is hollow at the bottom because of which its average density is lees than that of water so the ship is able to displace water equal to its weight and hence it floats.
30. How can a submarines float or submerge in water?
31. Submarines have ballast tanks at its basement. When it is to be submerged,these tanks are filled with sea water.As a result its weight becomes more than the weight of water displaced.So it submerges
32. If the submarine has to come up,the tanks are emptied out ,so the weight of the submarine decreases in comparison to the weight of the water displaced and the submarine rises up to the surface
33. The fishes Some species of fishes have swim bladder. When fishes want to rise they fill this bladder with gases diffused from their own body. Thus becoming lighter and to go down they empty their bladder thereby increasing their density and hence manage to sink
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35. Hydrogen and Helium filled balloons and hot air balloons tend to move upwards because the density of hydrogen is about 1/4th of the air. The upward force is more than the downward force of the balloon and hence it rises upwards till the density of both becomes same
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