Unit A Section A2 Introduction The Particle Model
Completion requirements
Section 2: Fluid and mixture properties can be explained with the particle model.
Unit A: Section 2 – Introduction
Alloys
Figure A.S.2.1 – Steel is a mixture of iron metal and carbon.
Humans use metals for many purposes. We use metals to make buildings, tools, and vehicles. However, many common pure metals aren’t ideal materials. For example, iron metal is strong, but it rusts and forms holes easily. Some metals, like aluminum,
don’t rust easily, but they’re not very sturdy.
To solve this problem, ancient civilizations discovered that different metals could be melted and mixed together to form a mixture with the best properties of both metals. A solid mixture of metals looks like a single type of metal. It is called an alloy.
Humans use alloys daily. Steel is an alloy made from iron and carbon. Steel has the strength of iron, but doesn’t rust as quickly. Cars and buildings contain steel parts. Stainless steel is an alloy of iron, chromium, and various other metals. Stainless steel is strong but is very resistant to rust, which is why it is used to make sinks and medical tools. Brass is an alloy of copper and zinc. Brass is durable but easy to bend, which is why it is used to make musical instruments.
To solve this problem, ancient civilizations discovered that different metals could be melted and mixed together to form a mixture with the best properties of both metals. A solid mixture of metals looks like a single type of metal. It is called an alloy.
Humans use alloys daily. Steel is an alloy made from iron and carbon. Steel has the strength of iron, but doesn’t rust as quickly. Cars and buildings contain steel parts. Stainless steel is an alloy of iron, chromium, and various other metals. Stainless steel is strong but is very resistant to rust, which is why it is used to make sinks and medical tools. Brass is an alloy of copper and zinc. Brass is durable but easy to bend, which is why it is used to make musical instruments.
Figure A.S.2.2 – Brass is a mixture of metals used to make musical instruments.
Figure A.S.2.3 – Stainless steel is a strong rust–resistant alloy of mostly iron and chromium metals.
Watch More
Bronze Age
Bronze is a mixture of copper and tin. People started making bronze during the Bronze Age 5000 years ago. Bronze revolutionized the way people made tools and weapons. This video re–enacts how Bronze Age people created bronze.
Bronze is a mixture of copper and tin. People started making bronze during the Bronze Age 5000 years ago. Bronze revolutionized the way people made tools and weapons. This video re–enacts how Bronze Age people created bronze.
Ore to Steel
Steel is a necessary alloy for modern life, because it’s used to make so many structures. Watch this video to see how steel is manufactured from iron ore and carbon-containing coke.
Steel is a necessary alloy for modern life, because it’s used to make so many structures. Watch this video to see how steel is manufactured from iron ore and carbon-containing coke.
Dental Amalgams
Cavities are holes that damage people’s teeth. Dental fillings stop cavities from getting deeper and more painful. One dental filling material is amalgam. Amalgam is a mixture of liquid mercury metal, silver, tin, and copper. Liquid mercury allows the filling to flow into the cavity, and the other metals help it solidify. Watch this video to see how a cavity is filled with amalgam.
Cavities are holes that damage people’s teeth. Dental fillings stop cavities from getting deeper and more painful. One dental filling material is amalgam. Amalgam is a mixture of liquid mercury metal, silver, tin, and copper. Liquid mercury allows the filling to flow into the cavity, and the other metals help it solidify. Watch this video to see how a cavity is filled with amalgam.
New Alloys
Lightweight but strong metals are useful in airplanes and cars. Scientists are constantly developing new alloys, such as lightweight magnesium alloys. Watch this video to learn more.
Lightweight but strong metals are useful in airplanes and cars. Scientists are constantly developing new alloys, such as lightweight magnesium alloys. Watch this video to learn more.
Words to Think About:
Check out the word cloud below. It pictures the important words that you are going to learn in this section. Watch for these words, and combinations of these words, as you read. When you see them highlighted, you can click on them to learn more about
what the word means. You can also visit the course glossary and read definitions for all of these words.
Lessons in This Section
Lesson A3: Pure Substances and Mixtures
Key Question – What are the different classifications of mixtures?
Lesson A4: Solubility and Concentration
Key Question – How do we compare the strengths of different solutions?
Lesson A5: Solubility ChangesKey Question – How can we make substances dissolve faster?
Lesson A6: The Particle Model and Mixtures
Key Question – How does the particle model explain dissolving?
Reading and Materials for This Section
Science in Action 8
Reading: Pages 18–37
Materials Lists for Unit:
Think • Interpret • Decide
Gold Penny
Watch this video to see a copper penny be coated with zinc and heated. What changes do you notice?
Watch this video to see a copper penny be coated with zinc and heated. What changes do you notice?
Questions:
After you have finished watching the video, carefully consider the following questions. Then, type or write your answers. When you have your answers, click the questions for feedback.
After you have finished watching the video, carefully consider the following questions. Then, type or write your answers. When you have your answers, click the questions for feedback.
A zinc coating is applied to a copper penny. The penny is then heated, which makes it turn it a bright gold colour.
Zinc and copper are the two substances involved in changing the penny’s colour. They are combined and heated. When heated, the two metals mixed together.
Zinc particles from the coating and copper particles from the penny melted together to form an alloy on the penny’s surface. From earlier in this introduction, you might recall that zinc and copper form the alloy brass. The penny is coated with brass.