Density and Pressure Flashcards
What is pressure?
How much force is put on a certain area.
What is the formula for pressure?
Force/Area
What is force measured in?
Newtons (N)
What is area measured in?
Metres squared (m²) or centimetres squared (cm²)
What is pressure measured in?
Newtons per metre squared (N/m²) or newtons per centimetre squared (N/cm²).
What is 1 N/cm² in N/m²?
10000 N/m²
Do you exert more pressure standing on one or two feet?
One, because the area is lower.
How do you find the force of an object?
Weigh the object on a Newton meter, or weigh it and times the object by 10 (mass to weight).
What is a Pascal?
1 N/m²
How do you calculate the area of an object?
Outline the object on a piece of centimetre-squared paper, and count how many squares are inside the shape.
When there is a set force, what does decreasing the area do?
Increase the pressure.
How do skis work?
It increases the area of your foot, so the pressure decreases, meaning you don’t sink.
What is density?
A measure of the compactness of a substance.
What is the formula for density?
Mass/volume.
What are the values for density?
g/cm³ or kg/m³
What is 1 g/cm³ in kg/m³?
1000kg/m³
How could you find the mass of solids?
Using a mass balance.
How could you find the volume of something irregularly shaped?
Measure out a certain volume of water in a beaker, and then add the object. Measure the now changed volume of water. Subtract the first measurement from the second, and that’s the volume of the object.
How could you find the volume of something regularly shaped?
Multiply the 3 dimensions of the object.
How could you find the mass and volume of a liquid?
Take an empty beaker and measure it. Then add the liquid, and the change in the number is the mass. Read off the beaker to find the volume.
Does a less dense liquid float on a more dense liquid?
Yes
What are immiscible liquids?
Liquids that don’t mix together.
How can you test the density of two immiscible liquids?
Add equal amounts of the liquids to a beaker. Then wait, and the liquids will form different layers. The liquid on the top layer is less dense than the bottom one.
How is density affected?
By the way the particles are arranged.
Usually, what are the most, middle and least dense states?
Solids, liquids and gases.
What happens when you heat a substance?
The particles move further apart, which could cause a change in state. This means the density will be lowered.
What would happen if you mix warm and cold water?
The warm water would float above the cold water.
What happens when you decrease the temperature of water?
The particles get spread out more.
Is water more dense than ice?
Yes
How could you measure the density of a gas?
Find the mass of a deflated balloon, and then inflate it with the gas, and re-measure the mass. The put the balloon in a container of water, and the volume change is approximately equal to the volume of the gas. Divide the mass with the volume to get the density.
What is approximately the density of air?
0.001 g/cm³
