Density
Buoyancy
Properties of Water
Engineering et al.
Archimedes' Principle
100
What is density?
The amount of matter in a given space or volume.
100
What is buoyancy?
The ability of an object to float.
100
What is the density of water?
1 g/mL
100
Why is it important to prototype during the engineering process?
So flaws can be assessed and remedied.
100
How can you measure the volume of an object using water?
The amount of water displaced is equal to the volume of the object.
200
What is the formula for density?
Density = Mass / Volume
200
Explain this image:
The object is floating because the buoyant force is equal to the force of gravity, ergo no net force is acting on this object, so it is floating.
200
What is fluidity? What types of matter exhibit fluidity?
The ability of molecules of a substance to move around one another. Gases and liquids exhibit this.
200
Why is it important to blueprint prior to building or prototyping?
To ensure that all dimensions of what you are building are already decided on and it can be accurately built.
200
According to Archimedes' principle, why would an object sink?
The mass of the object is greater than the mass of the water it displaces.
300
If you have an object with a mass of 55 grams and a volume of 15 mL, what will be its density?
3.67 g/mL
300
In water, how can you tell what percentage of an object is under water?
It is equal to the density times 100.
300
What is viscosity? How does viscosity affect the ability of an object to move through it?
Viscosity is the measure of a liquid's fluidity. The more viscous a liquid, the slower an object moves through it.
300
If the above rectangle has a mass of 65 grams, what will be its density?
Will it float on water?
0.90 g/cm3
Yes, it will float.
300
What does Archimedes' principle state about floating objects?
The mass of a floating object is equal to the mass of the water it displaces.
400
Harrison has a rectangular prism with measurements of .30 cm by .25 cm by .6 cm. If the object's density is 1.5 g/cm3, what is its mass?
Volume = 0.045 cm3
Mass = .0675 g
400
What percentage of a piece of styrofoam will be above the surface of water is it has a mass of 11 grams and measures 5cm by 1cm by 2.5cm?
12%
400
What is surface tension? How does it work?
Surface tension is the extra force of attraction between surface molecules in water. Water molecules have cohesive forces between them; at the surface, they have no molecules above them, ergo they are extra attracted to the molecules around them. This causes surface tension.
400
What is the volume of this cylinder?
62.8 cm3
400
What purpose did the outside material (bottles, styrofoam, bubble wrap) serve on your boat?
Increase the buoyancy of the boat and allow it to sit higher in the water.
500
Giselle has this cylinder and needs to figure out its density:
If the mass of the cylinder is 3100g, what is the density? Will this cylinder float?
The density will be 1.03 g/cm3 and it will not float.
500
What is neutral buoyancy?
When an object's density is equal to the density of the liquid it is in.
500
What is the mass of 500 mL of water?
500 grams
500
If the above cylinder has a mass of 1050g, what is its density? Will it float?
Volume = 942 cm3
Density = 1.11 g/cm3
It will not float.
500
How do boats work?
They spread mass over a larger area, displacing a greater amount of water, allowing them to float.