Physics in experiments Dominika Liptáková Dominika Duchová

What Slovakia doesn‘t have... Greece – sea Romania – sea Poland – sea Hungary – Balaton

We have the High Tatras

That‘s why we are going to show you water‘s experiments

Archimedes΄principle States that the buoyant force is equal to the weight of the fluid the object displaces Fvz = V . ρ . g F VZ - buoyant power V - volume ρ - density of liguid g - acceleration of gravity

Archimedes΄ principle of floatation Depends on: the density of fluid volume of object If object less dense than fluid, it will float If same density,than it will neither sink nor float If object denser than fluid, it will sink

What are we drinking? Water is able to pick up a tin

What do we need? coat hanger nut twine 4 bottles water

When is buoyant power stronger? The buoyant power is stronger if the objects have the same mass and different volume

same mass different volume same gravitačná power väčší objem, väčšia buoyant power

When is buoyant power stronger? The buoyant power is stronger if the objects have the same volume and different mass

same volume same buoyant power different mass

Problem

Density of water - 1000kg/m3 Density of aluminium - 2700 kg/m3 If object denser than fluid, it will sink Conclusion: Archimedes' principle can not be applied

Tension of surface liquid Tension of surface liquid- are molecules which have distance shorter than rm / radius/- It is like flexible membrane,which encircle the surface of liquid.

Cartesian / diver/ Water is much denser than air. So when you push more water inside the dropper, you increase its overall density. Once its density is greater than that of its surroundings, it will sink. Experiment: You fill a clear plastic bottle with water and place an eye dropper in it. The eye-dropper should have just enough water inside it so that it barely floats. Now seal the bottle tightly and squeeze on its sides. The eye-dropper sinks! Stop squeezing and the dropper rises once more.

Cartesian / diver/ Release the pressure on the bottle’s sides and you stop forcing water inside the eye- dropper. The air inside it will now push out the extra water again, and the eye-dropper will rise.

Does the water level have to be horizontal? Water can curve the surface The centrifugal force acts on the water particles Tornado in the air and in the water?

Water confirms diffusion

Thank you for your attention