S Density Flashcards
What is density?
Density is the mass of 1cm^3 (cubed) of a substance
How do you find the density of something (in steps)?
- Find the mass of the object.
- Find the volume of the object.
- Use the formula Density = mass/volume
What is the formula for density?
Density = mass over volume
List the steps of an experiment that finds the density of an irregular-shaped object.
To find the density of an irregular-shaped object.
Steps:
The mass of the object is found by placing it on a balance.
the volume of it is found by lowering it into a filled overflow can and noting the volume of water that flows out using a graduated cylinder.
Divide the mass of the object by the volume of water to get the density of the object.
List the densities of some common substances that have a density lower than water.
Polystyrene - 0.02 Cork - 0.3 Paraffin oil - 0.8 Ice - 0.9 (Water) - 1.0
List the densities of some common substances that have a density higher than water.
Brick - 2.0 Aluminium - 2.7 Lead - 11.2 Mercury - 13.6 Gold - 19.3
What is the density of water?
The density of water is 1g/cm^3.
Why do some substances float on water and some sink in water.?
Substances that float on water have a lower density than water and substances that sink in water have a greater density than water
What can gases do depending on their density? Give 2 examples of this.
Gases can float or sink in air depending on their densities.
A Helium balloon will float in air because helium has a lower density than air.
However, carbon dioxide sinks in air as carbon dioxide has a higher density than air.
List the densities of some common gases.
Helium - 0.0002
Air - 0.0013
Carbon dioxide - 0.0020
What does air do when it is heated?
When air is heated it expands and its density decreases. Therefore hot air will rise (float) over cold air. The same happens in liquids.
List some reasons why density is important.
Density can help us predict if something will float or sink.
If we know the density of a substance, we can predict what the substance is e,g geologists use density to identify rock types.
Engineers take density into account in design e.g. An aircraft uses metals of low density that make it easier to fly.
Lower density components are used to keep items as light as possible e.g. suitcases.
Energy-efficient cars use low-density components to keep them light and save fuel.
Why does an iron ship float?
Iron has a greater density than water. An iron ship floats because the average density of the ship is less than that of water.
What is the densest substance? And what was it used for?
Osmium is the densest element of all. It has a density of 22.6g/cm^3. Osmium was used in the nibs of fountain pens and in the filament of light bulbs (Osram brand).
What is one of the densest bodies in our solar system?
What would its density be?
What can it turn into?
A neutron star is one of the densest bodies in our solar system.
It would have a density of about a billion g/cm^3.
It can collapse again into a more dense body called a black hole.
