Astronauts use "Astronomical Unit" to measure the distance between planets in our solar system "only". To measure long distances like between 2 galaxies, they use "light years". One Astronomical Unit = Average distance between sun and earth which is equal to 149.6 million kilometers. Ping me if you have any doubt.
First, we'll identify the beaker containing pure water as follows:
We'll take equal masses from each of the three beakers and measure the mass of each.
We'll then identify the density of each by using the rule : density =mass/volume
Pure water will be the liquid having density equal to 1 gm/cm^3
Then, we'll differentiate between the salt and sugar solution by measuring the conductivity of each solution. Salt solution is a good conductor while solution of sugar is a bad conductor.
Surface tension, property of a liquid surface displayed by its acting as if it were a stretched elastic membrane. This phenomenon can be observed in the nearly spherical shape of small drops of liquids and of soap bubbles. Because of this property, certain insects can stand on the surface of water.
