Physical and Chemical Properties of Water
This activity will set up a series of experiments that will help students identify and find physical properties of water. A discussion of what the students know (or believe they know about water) will start this activity. Once the properties are discussed, methods of testing these properties will be discussed by the instructor, leading the students into the students' development of these labs.
o This activity is designed for the students to learn laboratory techniques—both physical and mental.
o This activity is designed for the students to develop their skills in using previous knowledge to develop further testing of items.
o This activity is designed to help students understand the concepts of Physical and Chemical Properties.
o This activity is designed to help students understand the concept that properties help to identify substances.
- Chemical Property
- Physical Property
- Boiling point
- Melting Point
Context for Use
- I use this as a structure for my 9th grade Physical Science class to get the students to see that they have the abilities to think (tie previous knowledge into the current situation and to extend into new situations).
- Class size varies from approx. 22-36. The discussions are usually done as a full class (fine tuning of ideas and understanding is usually done while the students are working on paperwork or in the lab).
- This activity is a work in progress for the first half of the year—I use this for approx. the first half of the year as we discuss and work with different physical properties—continually tying previous knowledge to what they need to do next.
- Basically this a framework for the first half of the year that can change direction as the students come up with questions, ideas and desires to learn about a specific Physical Property. Water is the easiest and safest chemical to use with this age level. Other chemicals that I incorporate are Isopropal Alcohol, Salt, Sugar, Charcoal (had problems with Sulfur allergies/reactions), Sand, and an assortment of insoluble solids.
Resource Type: Activities:Lab Activity
Grade Level: High School (9-12), Middle (6-8)
Description and Teaching Materials
- As the students tell what they know (brainstorm) about water, lead them to properties and ask them how to test these properties.
- The list of properties most students know include; freezing point (difficult to do), boiling point (easy), items float or sink in it (lead to density by giving items that float and some that sink and ask what is the difference—weight, size, etc.—take this to Density), flammability (lack of, yes it is a Chemical property) vs. other clear liquids (Isopropanol), and solubility (making Kool-Aid, careful for the debate on whether solubility is a chemical or physical property). These are the main items that can cover most of the lab techniques that the students will use in later lab classes.
- Begin with whatever Physical property you feel is easiest, you are most comfortable with, or you think the kids need to do (sometimes they need to 'burn' off a bit of lab energy). I will begin with Density of Regular shaped objects and ask which float or sink, then will go into Irregular Shaped Objects, then finally Density of Liquids. Many times I also fill in Boiling Point to keep interest (flames).
- I use this method to tie previous knowledge to the Physical (and Chemical) Properties of water and then to other items (solids and liquids). I finish off the properties with the classic IPS (Introductory Physical Science) lab—SLUDGE.
- A container is given to the students that contains the following: Water, Isopropanol, and Salt, along with some combination of insoluble solids in powder-like form (Sulfur, Charcoal, Ferrous Oxide), insoluble solids in large-form (metal cubes, rubber stoppers), and insoluble solids in 'BB' form (copper, zinc, iron, lead). The students then are given five lab days to separate and identify (finding physical and chemical properties), and then approx. 3 days to prepare their report.
Teaching Notes and Tips
9-12.I.B.2 Qualitative vs. Quantitative
9-12.I.B.3 Use of Mathematics
9-12.I.B.4 Sources of error
9-12.I.C.2 (use of electronic measuring instruments)