1. all matter is made up of very small particles. particle ... · 07.12.2017 · particle theory of...
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Particle Theory of MatterThe five major points of the particle theory of matter are:
1. All matter is made up of very small particles.2. All particles in a pure substance are the same. Differentsubstances are made of different particles.3. There is space between the particles.4. The particles are always moving. As the particles gain energy,they move faster.5. The particles in a substance are attracted to one another.The strength of the attractive force depends on the type of particle.
DEMO: “Oobleck”, “non-Newtonian fluid” Called Magic Mud on p. 269 (in case you want to do at home)
Materials Needed: 150 ml (10 tablespoons) cornstarch, 90 ml (6 tablespoons) water, food colouring , Mixing bowl and spoon
Scientific Explanation: When the corn starch is mixed with water, it does not dissolve; it forms a suspension. The cornstarch and water mixture (“magic mud”) acts as a solid when pressure is applied; and a liquid when sitting because there are two states of matter in one...Chemists call this type of mixture a colloid.
When it is “shocked” or sudden pressure (squeezing, picking up, stirring) is applied, most of the water runs out from between the grains of corn starch leaving solid corn starch particles to act like a solid. As soon as the pressure is released, the water flows back in between the grains, causing the mixture to “act fluid” again.
Viscosity =
a) the “thickness” or “thinness” of a fluid
7.2 Viscosity and Flow Rate READ: p. 278 - 281
Viscosity = b) resistance to ____________________.
The particles can move around but it may be more __________________ for them to pass by each other, it depends on the type of particle.
Examples:
Molasses vs. water
molasses (Sucrose = C12H22O11) Ethanol = C2H6O
*Used in Vanilla Extract FYI
Why is Viscosity important to us? see p 278 - 279FOOD INDUSTRY:
● Ingredients added to foods to give the right thickness to make appealing ● Ex. of chocolate bar production
Examples of foods that are thickened:
● Protein shakes, milk shakes, medicines, chocolate,
Why is Viscosity important for maple syrup production? Read p 279
● don't want too runny, producers test it for ● want certain % sugars for right viscosity● boiling down evaporates the water leaving the
sugars
Everyday Products:Examples:
● paint
https://www.youtube.com/watch?v=V5a4kP-5Jiw
These numbers are often referred to as the "weight" of a motor oil.
W = viscosity when cold
Ex; 10W-30 designates a common multi-grade oil.
The first number '10W' is the viscosity of the oil at cold temperature
The second number is the viscosity at 100 °C (212 °F).
https://docs.google.com/document/d/1edAvs9sgtp2ObhkAp-aPKibHnhzY7KJpqBMcvdkxMuU/edit
DEMO: How is the flow rate of a liquid related to its viscosity?
PREDICT: Which fluid will be first?
Flow Rate (p 281 -283)Water vs molasses vs oil Distance: ___61__ cm
Liquid Time (s) Flow Rate (cm/s) Ranked Flow Rate
Ranked Viscosity
shampoo 4:45 0.21 cm/sec
Molasses 1:27 0.70 cm/sec
Cooking Oil 0:05 12.2 cm/sec
Honey 22:08 0.0005 cm/sec
How is the flow rate of a liquid related to its viscosity?
Describe two sources of error that affect results:
The faster a liquid flows,
The less viscous it is……
(or the other way around)
INVERSE relationship* (in all of science: either direct or inverse relationship)
HOMEWORK:In your notebook: p 281 Q 1 - 4 (brief answers)
1. What is meant by the flow rate of a substance?2. What is the relationship between the viscosity of a liquid andits flow rate?3. How can you test the viscosity of a liquid?4. List two substances that have a low viscosity and twosubstances that have a high viscosity.