Water flows the most freely, or the most quickly. You would probably never think of water as a thick liquid.

Takamasa Takahashi, a physicist at St. Norbert College in De Pere, Wis., attempts a definitive answer: “Cold water does not boil faster than hot water. The rate of heating of a liquid depends on the magnitude of the temperature difference between the liquid and its surroundings (the flame on the stove, for instance).

So hot water takes up more space than cold water. Hot and cold water are made of the same type of molecules. Each molecule has one oxygen and two hydrogen atoms. The difference between them is the speed of the molecules jiggling around.

Answer: The marble will drop the fastest in the water and slowest in the glycerol. The reason is due to the different viscosities of the fluids.

Yes, friction exists in fluids but it presents itself differently than friction between solid objects. The drag friction is always proportionate to the fluid’s viscosity. With viscosity, drag friction varies with the square of the velocity of the fluid relative to the container in which it flows.

Water is the least viscous, then vegetable oil, and hand soap is the most viscous. 2) Measure the height of the fluid in each glass using a ruler and note down the mass of each block of clay from the package.

Explanation: The more viscous substance contains longer chain molecules which have greater inter-molecular bonding, which causes the greater viscosity.

The surface tension of hot coffee is definitely less than that of cold water – that much is for certain.

The coffee is slightly less dense than the milk, so it has a tendency to float on top. The cooling liquid at the sides becomes denser and starts to fall down until it meets liquid that has slightly higher density due to the proportions of its milk-coffee blend.

The method we use most and gives us the most accurate results is the water displacement. When evaluating the density of our green coffee beans we’re looking for the coffee beans to sink in water, as they should be denser than water. This is because water has an equal mass to volume ratio of 1.0 g/ml.

In the video below, MIT scientists explain that when the drop of cream first hits the surface of the coffee, a bit of air becomes trapped between the drop and the rest of the liquid. Anyone who has admired the swirling patterns cream makes in coffee can appreciate this finding.

It’s the unintentional curdling of milk that’s past its expiration date, or has been left out all day, that can make you sick. But if it’s perfectly fresh and it curdles in your coffee, there’s no harm in drinking it.

According to Science Notes, milk sometimes curdles in coffee and tea because the acidity is just high enough to alter the pH of the milk. This usually happens when you add milk to very hot or acidic coffee or tea. But beware: Milk can also curdle in coffee right before the milk is about to turn sour.