Student Activity Sheet
When you are asked to describe a person you know, what do you do? You tell about that person’s physical features. You might mention how tall someone is, describe the way their body is built, and give the color of their eyes and hair. Physical properties are the way scientists use to describe matter of any kind. You could say that these are the characteristics of a material. They can include the color of something, how it feels when you touch it (texture), whether or not it has an odor, and if it does, what kind of odor. Other characteristics are the shape of the material, whether or not it will flow (only for liquids), as well as mass and density. In this activity you will examine 7 liquids and 3 powders. You will describe and record your observations of certain physical properties.
10 petri dishes or clear containers with covers containing unknown samples (already set up by your teacher.)
Examine the samples. You are to describe each sample in the following way:
ability to flow (viscosity)
shape of particles (use magnifying glass)
Use the number on the container to identify your samples. You will be given each sample’s identity at the end of the activity.
@2H(after1H):Examining a Chemical Reaction
Teacher’s Lesson Plan
Students will observe what occurs during a chemical reaction.
Depending on the class, students can either do a lab write up or answer the questions at the end of the activity. The activity sheet has been written up so that the questions are to be answered. If a lab write up is chosen, omit the question section.
See student activity sheet.
1. Explain the definition of chemical reaction. Discuss with the class the terms
reactants and products. include in the discussion the signs or evidence of a
chemical reaction. If possible, do a demonstration of combining chalk with
vinegar. (The chalk will bubble as it is reacts with the vinegar.)
2. Hand out the activity sheet; allow students to get materials and do the experiment.
Remind them to touch the bag as the reaction occurs.
3. Instruct the students to notify you when the reaction is completed. This is when
the gas will be tested to see if it supports combustion (burning). Light the candle,
have one student carefully open the bag. Barely insert the candle into the bag or
hold it just at the opening. The flame should go out.
4. After students have completed the activity, but before they complete the questions
lead a discussion that would highlight the subjects addressed by the questions.
5. Students answer the questions.
Questions to be used:
1. What happened when the baking soda and vinegar were mixed?
2. How did the bag feel when you touched it while the reaction was going on?
3. What caused the bag to expand? Do you know the name of the material?
4. What happened when the lighted candle was placed near the opening of the bag?
5. Some gases have the chemical property of being able to support burning (allow something to burn). Does this gas have that property?
6. Another chemical property that a gas may have is the ability to burn itself. This is called flammability. Is this gas flammable?
7. How could you learn more about the material that caused the bag to expand?