Frequently Asked Questions
Question: How do you manage all the equipment and chemicals?
Answer: First of all, get enough rubber tubs (cheap tubs will do) for each group, and one demo tub. For a class of 24-30, 6-8 tubs are enough.
Separate the supplies into each tub.
List for each tub:
Balance
Filter stand
3 cups for the balance
Post-it notes
Gram cubes in a baggie (get for the measurement kit or order from a science math catalog or base ten block kit).
Question: What are the unit specific concept words that students should understand?
Answer: The Foss Mixtures and Solution book has word bank words at the end of each lesson. They are listed here for your convenience.
• Mixture
• Solution
• Dissolve
• Property
• Evaporation
• Crystal
• Solute
• Solvent
• Saturated
• Solubility
• Concentration
• Dilute
• Volume
• Chemical reaction
• Precipitate
• Change
• Reactants
• Filtration
Question: How do you manage the handouts and work sheets?
Answer: Put the response and worksheets together in a packet at the beginning of the unit, except for Handout #10, which should be handed out at the time of the investigation. As the students are working on each lesson, you can either have them tear out the sheets to turn in or have them turn in their packets at the end of each week for feedback. At the end of the unit, they can turn in the entire packet for a final grade. This saves you from remembering to copy the handouts for each lesson. Also, include the instructions for each job in the student groups. These instructions are described on page 8 of the overview section of the teacher's manual. You can also add the procedures for each lesson in the packet. See the next question.
Question: How do you manage giving instructions to the class, and make sure the students understand the instructions (to save you from repeating the instructions several times)?
Answer: Each lesson, under the Guiding section, has a series of steps for each experiment. Make a procedure handout for the steps the students need to do during the experiment. This can be added to the packet, or given as a separate handout the day of the experiment. This is very helpful because the students have instructions right in front of them in a step-by-step format. It is assumed that all materials are in the students' tubs unless they are told to go and get something from a station.
It is also helpful to make an overhead of the instructions to point to. That way, you can review the instructions as a group before each experiment, and then the students have something to refer to as they are working.
This helps model procedure writing for the students. In later lessons, students have to plan and write their own procedures before doing the experiments.
Instruction writing takes a little time as you first use a kit. But, it saves a lot of time and frustration later on, and you only have to create these instructions once.
Example Instructions
Lesson 1. Making and Separating Mixtures
• Reporter labels 3 cups with post-its G, P, and S.
• Getter 1 takes the labeled cups to the chemical location, gets several mls of each substance, and puts them in the corresponding cup.
• The group should observe and record findings about the appearance of each substance on the Separating Mixtures page.
• After sharing your findings, and when told, Getter 2 gets 50ml of water in the syringe and brings it back to the group and adds it to the gravel cup.
• The cup is then stirred and observed. The results are recorded in part 2 of the worksheet.
• Repeat steps 4 and 5 for the other 2 cups.
• Reporter labels a second set of empty cups G, P, and S.
8. Go on to part 3 of the worksheet and follow the instructions.
Student Preconceptions about your content area
Describe tools used to determine student preconceptions:
Classroom discussion is the best way to assess the students' ideas about matter.
• Use open-ended questions to start.
• Move to the narrow, more specific questions to focus the students on a topic and correct misunderstandings.
To start this unit, I have the students read the first story in the student book. I read the story aloud and have the students follow to accommodate the lower readers in the class. Then, I'll have the students work in pairs to answer the questions. We then have a class discussion. I have a periodic table chart in the room for the students to look at. It is a point of interest for most students, but should not be a main focus for this unit. The teacher's manual in the FOSS story section has suggestions for discussion questions.
Description of a student preconception (naïve conception, misconception, incomplete conception):
Students believe that when a chemical dissolves, it has changed form.
They also do not understand that all elements/molecules will go into any of the 3 states of matter depending on temperature.
They believe that in a chemical reaction, chemicals disappear.
They do not understand the scientific inquiry process.
They do not understand how elements can be separated.
They do not understand that molecules come in specific shapes but can be different sizes.
Correct conception by the end of the unit:
Students know that matter comes in three states.
Explain how if we had a closed evaporation system the evaporated water could be seen as condensation in a collection tube. Give them the example of a boiling pot with a lid and if the lid is taken off there are water drops on the inside which is condensed steam from evaporating water, the gas state of water.
Matter is conserved but can change forms.
Matter is made of atoms combined to make molecules.
Molecules of the same shape can be different in size.
In Investigation 1, Part 3, after students compare the shape of their salt crystals to the smaller crystals of salt they started with, they should notice that the crystals are the same shape.
Chemicals can be separated and identified by their specific properties.
Description of a student preconception (naïve conception, misconception, incomplete conception):
Regarding solutions:
• Different than a mixture
• Since one substance disappears, a chemical has changed or a reaction has happened.
Correct conception by the end of the unit:
The students understand that a solution is a mixture and can be separated through evaporation and the original parts can be identified.