INCOMPLETE Grade 8 Unit A Test (Section 3-4) Flashcards
Up to 4.1? Review of topics in Unit A slides from sections 3&4. It also has information related to these sections
What is viscosity?
Viscosity is a substance’s resistance to flow. If a substance as a high viscosity it has a low flow rate, and vice versa.
What is flow rate?
How quickly fluids can flow
How is flow rate measured?
Distance over time. For example km/h
What determines the viscosity of a substance?
The internal resistance or friction between the particles of the substance.
What happens if there is more friction between the particles?
It flows slower and has a higher viscosity. In a river, the water at the bottom flows slower because there is friction against water and sand. The water at the top flows faster because there is no friction stopping it.
How does heat in a liquid affect viscosity?
The particles spread, vibrate faster, and have more energy. This extra energy allows the particles to slide over each other more easily.
What is an example of manipulating the viscosity of a substance?
In cold weather, motor oil becomes more viscous. Manufacturers need to make the pipes so that the thicker oil can flow during winter.
What are examples of a more viscous fluid? Less viscous?
Honey is more viscous than water.
What is density?
The amount of matter in a given volume.
True or false: Every substance has the same density
False. Every substance has a different density because they are made of different particles
What do we use to measure density?
A hydrometer
What affects a substance’s density?
The substance being solid or filled with air pockets. (The amount of particles in a given area)
If a substance is less dense than water and is placed on water, will it sink or float?
It will float. If it was more dense than water it would sink.
How do you calculate density?
Density = Mass ÷ Volume
What are the 3 manipulations of the density formula?
D = M/V, M = D×V, V = M/D
Which is the most dense? Solids, liquids, or gases?
Solids are the most dense. Gases are the least dense. Liquids fall in the middle.
Most fluids become denser as they cool down to their freezing temperature. What is the exception?
Water. It reaches its greatest density at 4°C and is 1g/ml
How do you measure density?
In solids it’s g/cm³ or kg/m³. In liquids it’s g/mL.
What is buoyancy?
The tendency of a substance to float
True or false: buoyant objects take up space in a fluid
True