Grades: Grades 6-8
Author: Jim Duxbury,Charlotte Szucs, Sandy Van Natta, and Mary Harris
Source: Phil Dodson from Harlingen, TX for the laboratory distillation idea.
Students will be divided into research teams. Each team will research how fractional distillation works, as well as describe one of the major products of fractional distillation. Students will then use distillation to separate 2 liquids. The concept of density will be used. (D=M/V).
What should students know as a result of this lesson?
What should the students be able to do as a result of this lesson?
Have some of the following present in the room for examination: car wax, Vaseline, motor oil, road tar, paraffin, grease, plastic items
Have a discussion about what these have in common. Students may need the Web to look up these substances.The teacher will listen to the class discussion and ask some of the following questions if needed:
The goal of the engagement is to have the students come to realize that they all are made from crude oil.
Student groups will be given the sheet “The Fractional Distillation Tower” and assigned one specific research topic. Each group should identify crude oil as the source of hydrocarbons, explain the process of fractional distillation, diagram a fractional distillation tower, and describe one of the products of fractional distillation. Each group receives 2 worksheets to guide them in their research.The teacher can move from group to group checking to see if all groups are recording information and actively involved in the research. Asking questions such as the following will check for student understanding:
Collecting and viewing the completed worksheets is another way of assessing student work. Looking at the site http://science.howstuffworks.com/oil-refining4.htm has a very nice tower.The high school component on the AGPA Web Site also gives some information and demonstrations about fractional distillation.
Students will construct a paper diagram of a fractional distillation tower on the classroom wall (one diagram for the entire class) and place the worksheet of their product at the appropriate location on the tower. The image they found should also be placed on the correct location.
Students will present to the class the information they learned about their product. Students should be encouraged to use diagrams and charts to present their information. A rubric is provided for assessing the group work at this stage. A copy of this rubric should be given to students before they start their research so that they are aware of the grading criteria.
Students will be given a mixture of two liquids: 25 mL water with 25 mL vegetable oil. They can be told that the boiling point of water is 100 °C and that the boiling point of oil is well above 100 °C. They are given a laboratory sheet of directions on how to distill the mixture.
The teacher must approve the distillation set-up and check the students’ density findings at the conclusion of the experiment.
Demonstration: This is in the engagement phase.
Direct Instruction: Set up a model of the distillation apparatus so that students can easily see what they need to do for the Elaboration.
Cooperative Learning: Students work in groups to research information, and distill a mixture of two liquids.
Others: Oral presentations will be used in this learning cycle.
Skills: Internet Use.
Misconceptions: Students will assume that the mixture will keep getting hotter and hotter as the water boils. They will not expect the temperature to stay steady until almost all the water has been converted to steam. Students may also think that the melted ice cube is dripping through the foil into the beaker.
Common Core Standards:
Goggles must be worn during the hands-on activity. Caution students that the heated mixture will be extremely hot and should be handled with care. SEE THE LABORATORY DIRECTIONS IN A SEPARATE FILE.
Crude oil is the source of hydrocarbons such as waxes, oils, and fuels. The products of fractional distillation can also be used as a source for producing today's plastics. Many of the products we use everyday started out as crude oil.
Grouping Suggestions: Divide your class into 8 groups since there are 8 major distillation products.
Pacing/Suggested Time: Research time will vary based on the availability of computers. Most of the research can be completed in 1 to 2 class periods on the computer. The actual distillation will take one period.