Mixtures & Solutions
Investigation 4
Part 1
Fizz Quiz
Students mix calcium chloride, baking soda and citric acid with water and observe changes.
3. Lesson set up and Management
Physical and Chemical Changes (CH01 1.3.3)
- Know that matter can undergo changes of state such as evaporation, condensation, or freezing and thawing. Grades K, 1, 2, 3, 4, & 5.
- Understand physical and chemical changes at the particle level and know that matter is conserved. Grades 6, 7, & 8.
Planning and Conducting Investigations (IN02 2.1.2)
- Plan and conduct simple investigations, using appropriate tools, measures, and safety rules. Grades K, 1, 2, 3, 4, & 5.
- Plan, conduct, and evaluate scientific investigations, using appropriate equipment, mathematics, and safety procedures. Grades 6, 7, & 8.
Explaining (IN02 2.1.3)
- Use data to construct reasonable explanations. Grades K, 1, 2, 3, 4, & 5.
- Use evidence from scientific investigations to think critically and logically to develop descriptions, explanations, and predictions. Grades 6, 7, & 8.
- When a change results from mixing two or more materials, that change is a chemical reaction. A reaction results in new materials.
- A gas is formed by some reactions.
- A precipitate occurs in some chemical reactions.
3. Lesson set up and Management
Materials:
Check the list in the manual and be sure the student tubs are restocked.
If you did not make a packet as mentioned in the FAQ section, copy Handouts #14, one per group, and Handout #15 for each student.
Put the chemical out at the chemical station. If you can have two sets of chemicals at the station, this will cut down on wait time.
Have each chemical clearly labeled, and tell the students the importance of reading labels.
Have a separate spoon for each container and tell the students to prevent contamination by not mixing up the spoons or using the same spoon in multiple containers.
Calcium chloride will cake if left in the open. It needs to be in an airtight container until it is ready to use and resealed when done.
Student Management:
This is a great lesson for reinforcing lab safety.
Remind students that they need to wear goggles when handling chemicals.
Tell them to keep their hands away from their faces.
They also need to clean up spills.
Reviewing concepts is important, so students make connections to the other investigations.
If you have a periodic table poster in the room, the students will be interested in seeing the chemicals they are using. You can point out the elements that make up the various chemicals they will be using.
This investigation part has a number of steps, so it is helpful (and cuts down on mistakes) if these steps are reviewed with the class. A written, step-by-step procedure is also helpful.
At the end of the investigation, there is always a student who wants to know what will happen if all three chemicals are mixed together. Caution students that unless you have a good idea of what will happen, chemicals should not be mixed. Then tell them that since you know what will happen, they can try it.
Get lots of paper towels first. There is a lot of foaming as more carbon dioxide is created.
Experiment:
Materials:
3 plastic cups
3 stir sticks
50ml syringe
Sticky notes
5ml spoon
Fizz quiz placemat and observation sheet
Calcium Chloride (CaCl 2 )
Sodium Bicarbonate (NaHCO 3 )
Citric Acid (C 6 H 8 O 7 )
H 2 O
Procedure:
1. Label 3 cups # 1, 2, and 3 and place on a fizz quiz placemat.
2. Go to the chemical area and place a 5ml spoonful of CaCl 2 and 5ml spoonful of NaHCO 3 into cup #1.
3. Get 50ml of H 2 O, go back to your group, and carefully put it into cup #1.
4. Observe carefully and record results on your observation sheet (This is your data so do it!)
5. Prepare cup # 2 – Put 5ml of CaCl 2 and 5ml of C 6 H 8 O 7 into cup#2.
6. Add 50 ml of H 2 O at the group table.
7. Observe carefully and record results on your observation sheet.
8. Prepare cup #3 - Put 5ml of NaHCO 3 and 5ml of C 6 H 8 O 7 into cup#3.
9. Add 50 ml of H 2 O at the group table.
10. Observe carefully and record results on your observation sheet.
11. Discuss results with your group. What evidence do you have for a chemical reaction in each cup?
It is really important to have the follow up discussion. Otherwise, students may be confused by what happened and will not understand that a new product was formed.
The students must save cup # 1 for the next lesson.
It is easier to have a longer session one day and go right into the next lesson so the cups with the precipitate aren't sitting around the room. You can do the initial discussion and filtering, then wait a day or two to look at the results. It is really important to have the follow up discussion. Otherwise, students may be confused by what happened and will not understand that a new product was formed.
Writing Support:
Have the students write the definitions from the word bank and the answers to the inquiry questions in their journals. The students should complete Handout # 15, the response page, to turn in. Their answers should form the basis for the start of the next session's discussion.
Reading Support:
In the Mixtures and Solutions: Science Stories book, read “What a Reaction” and have the students answer the questions in their journals.