Unit A Lesson A12 Density and Viscosity
Completion requirements
Lesson A12: Fluid Technologies: Density and Viscosity
Video Lesson
Watch this video to learn more about some fluid technologies that rely on density and viscosity to operate.
Lesson A12: Fluid Technologies: Density and Viscosity
Figure A.4.12.1 – Motor oil coats engine parts to keep them running smoothly.
Figure A.4.12.2 – It is important to select the correct viscosity of motor oil for a vehicle.
Figure A.4.12.3 – There are many different viscosities of engine oil.
Reading and Materials for This Lesson
Science in Action 8
Reading: No text reading for this lesson.
Materials:
Aluminum foil, scissors, ruler, 50 coins (all the same type), large plastic tub, water.
Figure A.4.12.4 – The engine oil must protect the fast-moving parts of an engine.
Motor oil thinly coats the engine parts in vehicles, to ensure that all the parts run smoothly. The motor oil needs to stay at just the right viscosity, to continually coat the metal engine parts. If the viscosity of motor oil is too low, it won’t flow to the engine fast enough. If motor oil has a very high viscosity, it will drip off the parts instead of coating them.
Two main types of motor oil are monograde and multigrade. Monograde oil has a viscosity that changes with temperature. At low temperatures, monograde oil is viscous and slow-flowing. At high temperatures, monograde oil is less viscous. Bottles of monograde oil are labelled as “SAE-number”. The lower the number, the less viscous the oil. For example, SAE-20 oil is less viscous than SAE-40 oil.
Because its viscosity changes with temperature, monograde oil doesn’t work well on cars at low temperatures. For this reason, multigrade oils were developed. Multigrade oils contain additives that keep the oil at a flowing viscosity at both low and high temperatures. Bottles of multigrade oil are labelled as “number-W-number” The lower the first number, the better the oil flows at cold temperatures. Many Canadians use 5W-30 multigrade oils in their cars in the winter.
Watch More
Motor Oil Gets Your Engine Through Thick and Thin
Watch this video to learn more about different types of motor oil.
Watch this video to learn more about different types of motor oil.
Conventional oils help an engine run smoother than synthetic oils. This video explains the differences between conventional and synthetic oils.
Watch this video to learn more about what the numbers on motor oil bottles mean.
Figure A.4.12.5 – Windshield wiper fluid cleans dirty vehicle windows.
Figure A.4.12.6 – Transmission fluid makes vehicle gears switch smoothly.
Figure A.4.12.7 – Dipsticks are used to check the levels of some vehicle fluids.
Vehicle Fluids
Vehicles rely on a number of fluids in addition to motor oil.
A vehicle transmission transfers power from the engine to the wheels. It has gears that make the car wheels spin faster or slower. These fast moving parts require transmission fluid to keep them running smoothly.
Car engines get very hot, and can overheat. Fluid-filled radiator tubes help cool down cars. Radiators are filled with a mixture of water and antifreeze. The water absorbs heat from the engine and transfers it outside the car. As its name suggests, the antifreeze prevents the water from freezing at cold temperatures.
Brake fluid fills a hose between the braking pedal and the wheel brakes. When the brake pedal is pressed down, brake fluid travels down the line and applies force to the brakes. Power steering fluid makes steering wheels easier to turn. Windshield wiper fluid cleans dirt off car windows.
In order to have a long-lasting, smooth-running car, vehicle owners must pay regular attention to vehicle fluids. In particular, motor oil needs to be changed regularly because it gets dirty and stops lubricating the engine. You can check the levels of most fluids under the car hood. Motor oil and transmission fluid have dipsticks to pull out and check the quality and quantity of the fluid. Most other car fluids are in white plastic containers that you can see through and check the fluid level.
Vehicles rely on a number of fluids in addition to motor oil.
A vehicle transmission transfers power from the engine to the wheels. It has gears that make the car wheels spin faster or slower. These fast moving parts require transmission fluid to keep them running smoothly.
Car engines get very hot, and can overheat. Fluid-filled radiator tubes help cool down cars. Radiators are filled with a mixture of water and antifreeze. The water absorbs heat from the engine and transfers it outside the car. As its name suggests, the antifreeze prevents the water from freezing at cold temperatures.
Brake fluid fills a hose between the braking pedal and the wheel brakes. When the brake pedal is pressed down, brake fluid travels down the line and applies force to the brakes. Power steering fluid makes steering wheels easier to turn. Windshield wiper fluid cleans dirt off car windows.
In order to have a long-lasting, smooth-running car, vehicle owners must pay regular attention to vehicle fluids. In particular, motor oil needs to be changed regularly because it gets dirty and stops lubricating the engine. You can check the levels of most fluids under the car hood. Motor oil and transmission fluid have dipsticks to pull out and check the quality and quantity of the fluid. Most other car fluids are in white plastic containers that you can see through and check the fluid level.
Watch More
Forgotten Fluids in your Car
Watch this video to learn more about how to check car fluids.
Watch this video to learn more about how to check car fluids.
Connections
Figure A.4.12.8 – Oil sand is a mixture of bitumen crude oil and sand.
Figure A.4.12.9 – Oil sands near the Earth’s surface are mined.
Figure A.4.12.10 – Oil sands extraction and refining is a large part of Alberta’s economy.
>> Oil Sands Industry
Oil sands are very important for Alberta’s economy. Oil sands contain crude oil, which is used for many products in our everyday modern lives, such as fuel and plastics. The Athabasca Oil Sands in northeastern Alberta are one of the largest oil deposits in the world.
Some oil sands near the Earth’s surface are dug directly out of the ground by mining. Most oil sands are recovered by pumping hot steam and solvents into the ground to force it out.
The crude oil in oil sands is thick, viscous bitumen. Hot water is added to the oil sand to separate bitumen from the sand. At a warmer temperature, the bitumen becomes less viscous and floats to the surface of the water. First Nations discovered this separation process many years ago, when they used bitumen to waterproof their canoes.
Because bitumen is thick and viscous, it does not flow easily. For this reason, bitumen is mixed with other crude oil substances to make a diluted bitumen solution, or dilbit. Dilbit has a lower viscosity, so it can flow through pipelines more easily.
Oil sands extraction uses a lot of energy, to heat steam to pump bitumen out of the ground and to heat water to separate the oil from the sand. This use of energy is very expensive. As a result, oil sands recovery is only profitable when oil prices are high. When oil prices are low, it costs more money to extract oil sands than the price the oil can be sold for.
Watch More
Alberta's Important Oil Sands
This video provides an overview of Alberta’s oil sands industry.
This video provides an overview of Alberta’s oil sands industry.
Watch this video to take a tour of Alberta’s oil sands.
This video provides more information on oil sands mining.
Figure A.4.12.11 – Heavy container ships have wide bottoms to increase their volume.
Figure A.4.12.12 – Cruise ships carry thousands of passengers.
Figure A.4.12.13 – Small boats must displace water to float.
What Floats Your Boat?
Why do big metal ships float, when metal is denser than water? The answer has to do with the shape of the ship. A boat will float when its overall density is less than the density of water. Large ships have a wide metal shell that contains air. The combined density of the metal and air in the ship is less than water, which makes it float.
Another way to look at density and the buoyancy of ships is by Archimedes’ Principle. It says that an object floats if it displaces a mass of water equal to the object’s mass. A very dense metal will sink in water if it is packed into a small volume. A small volume does not displace much water. The same dense metal will float if it is shaped into a large volume and can hold air, reducing its density. A large volume displaces more water.
Why do big metal ships float, when metal is denser than water? The answer has to do with the shape of the ship. A boat will float when its overall density is less than the density of water. Large ships have a wide metal shell that contains air. The combined density of the metal and air in the ship is less than water, which makes it float.
Another way to look at density and the buoyancy of ships is by Archimedes’ Principle. It says that an object floats if it displaces a mass of water equal to the object’s mass. A very dense metal will sink in water if it is packed into a small volume. A small volume does not displace much water. The same dense metal will float if it is shaped into a large volume and can hold air, reducing its density. A large volume displaces more water.
Watch More
Buoyant Boats
These three videos explains why heavy metal ships float.
These three videos explains why heavy metal ships float.
This video explains Archimedes’ Principle. The famous story about Archimedes might have been about a ship rather than a crown!
This video explains how bulkheads in large ships trap air to prevent them from sinking.
Try It!
Float a Boat
Try this simple experiment to test how the shape of a boat affects its buoyancy.
Materials:
Try this simple experiment to test how the shape of a boat affects its buoyancy.
Materials:
- Aluminum foil
- Scissors
- Ruler
- 50 coins (all the same type)
- Large plastic tub
- Water
Safety Warning
Take care with scissors; don't cut yourself or anyone else!
Instructions:
- Cut 3 identical pieces of aluminum foil, with dimensions of 30 cm by 30 cm.
- On one piece of aluminum foil, fold up each side 5 cm to form the sides of the boat. The bottom of the boat should have dimensions of 20 cm by 20 cm. Make sure all the sides are high enough to prevent water from getting in the boat.
- Fold a second piece of aluminum foil in half. Then fold up each side 5 cm to form the sides of the boat. The bottom of the second boat should have dimensions of 5 cm by 20 cm. Make sure all the sides are high enough to prevent water from getting
in the boat.
- Fold the third piece of aluminum foil in half, and then in half again in the opposite direction. Then fold up each side 5 cm to form the sides of the boat. The bottom of the third boat should have dimensions of 5 cm by 5 cm. Make sure all the sides
are high enough to prevent water from getting in the boat.
- Fill the large plastic tub with water.
- Float the first boat in the water.
- Add 1 coin at a time to the boat until it sinks. Count how many coins the boat could hold before it sinks. Record your answer in a table like the one below.
Observations Table
Boat Base Area
Number of Coins Added Before Sinking
1 20 cm x 20 cm 2 5 cm x 20 cm 3 5 cm x 5 cm
- Repeat Steps 6 and 7 for the other two boats.
- Watch this video to see this experiment and its results:
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
The boat with the smallest base had the least volume. A lower volume increased the overall density of the boat and caused the boat to displace less water. As a result, it didn’t require much more added mass for the boat’s density to be higher
than the density of water.
The boat with the largest base had the greatest volume. A larger volume decreased the overall density of the boat and caused the boat to displace more water. As a result, the boat could hold a larger amount of added mass before its density became
higher than the density of water.
A World of BoatsBoats are one of the oldest forms of transportation. Different cultures around the world have built boats for thousands of years. Boats can travel across both short and long distances. They come in many different sizes and designs, and are powered in many different ways.
To learn more about different kinds of buoyant boats,
click here to Explore with Elsie.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to guide your learning.
Unit A Lesson 12 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here .
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
-
REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Be a Self-Check
Superhero!
Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
The tightly crumpled foil has a higher density than water, which is why it sinks. It has a small volume that cannot hold much air, which increases its overall density.
The lightly crumpled foil has a lower density than water, which is why it floats. It has a large volume that traps more air, which decreases its overall density.
The lightly crumpled foil has a lower density than water, which is why it floats. It has a large volume that traps more air, which decreases its overall density.
Deep ship hulls enable the ship to trap more air. This reduces the overall density of the ship to be less than the density of water, so the ship floats.
Diluting bitumen decreases its viscosity so it can flow freely through the pipeline. If bitumen is not diluted, it flows slowly and can plug up the pipeline.
Canada experiences large temperature extremes, from minus 30 degrees C in the winter to plus 30 degrees C in the summer. Multigrade oil maintains a low viscosity to effectively coat engine parts at both high and low temperatures.
When a boat gets a hole, water flows into the boat. This adds more mass to the boat and increases the density of the boat. If the water-filled boat becomes more dense than water, it sinks.