Question

2
Answer in few words:
19. How does the density of a fluid vary with
temperature ?
20. Describe an experiment to measure the
density of a piece of iron.
21. Describe an experiment to find the density
of a liquid
22. What do you know about density bottle?
23. What is the unit of relative density ?
24. A piece of wood floats on water while an
iron nail sinks in it. Why?
25. Why does ice float in water?
26. Why are icebergs floating on the sea water
dangerous for the ships?​

Answer 1

Explanation:

As the temperature increases, volumes of most of the liquids also increases and when the volume increases density decreases. Similarly, when temperature decreases, the volume of most liquids decreases which increases the density. However, water shows anomalous behaviour. Water has maximum volume at 4-degree Celsius and maximum density at 4-degree Celsius.

But when water is cooled down further its volume starts increasing and hence, the density of water decreases when cooled further below than 4-degree celsius.

24.

A piece of cork floats on water because the density of cork is less than the density of water whereas an iron nail sinks in the water because the density of iron nail is more than the density of water.

25.

Ice floats because it is 9% less dense than water. In other words, ice takes 9% more space than water, so one litre of ice is less than one litre of water...

20.

Density = mass/volume

To find the density of the material of a coin, we need to find it’s mass by common beam balance and its volume by measuring cylinder

To measure the mass of a coin

Let the mass of a coin shown by a beam balance = M (gram) = 50g (ray)

To measure the volume of coin

Initial volume of water = V₁ = 42ml

Final volume of water

When a coin is added in the cylinder = V₂ = 52 ml

Then volume of coin = V₂ - V₁ = 52 - 42

= 10 ml