Properties of Matter
Part 2: Mixtures and Solutions
Students will determine how impurities can affect the characteristic properties of mixtures.
INQF Generate a scientific conclusion from an investigation…and clearly distinguish between results and conclusions.
PS2A Use characteristic intrinsic properties such as…boiling point and melting point…to identify an unknown substance.
APPC Give examples to illustrate how scientists have helped solve technological problems…and how engineers have aided science…
- Impurities may raise or lower the melting point of a substance.
- Impurities may raise or lower the boiling point of a substance.
- Solutions have different characteristic properties than the substances that make up the solution. Depending on the ratio of each substance, the characteristic properties can vary.
- Inquiries 18.1 / 18.2: Be aware that the thermometer placed loosely in the beaker makes the set-up unstable and could be a safety concern. Thermometer “holders” are available in most scientific equipment catalogs.
- Inquiry 18.3: Students need to carefully observe the solder while heating. The melting points of the three samples are close enough that unfocused students may miss the order of melting and the color codes may disappear.
- Inquiry 18.1: The class discussion of results is a good opportunity for graphing. This may help students who are better visualizers of data rather than interpreters of the numbers.
- Changing Freezing and Boiling Points: This reading connects the data students have collected in Inquiries 18.1 and 18.2 to two real-world problems.
- About Alloys: This reading discusses the definition of, uses of, and benefits of alloys.
- The Samurai’s Sword: This reading is about the history of the samurai sword and how swordsmiths modify the properties of the sword blade.
- Ice Cream in the Old Days: This reading discusses how people enjoyed the properties of ice cream before freezers were invented.