1. Tommy performed an experiment to test the solubility of sodium chloride in water. After he completed his experiment, he discovered that he had a few unused grams of NaCl leftover in a beaker. What should he do with the excess NaCl?
A. Pour the excess back into the original reagent container.
B. Pour the excess into the trash.
C. Ask the teacher about the proper place to dispose of the waste.
D. Pour the excess down the sink.
2. Arthur is studying plants, and he wants to learn more about why tree leaves change colors in the fall. His teacher suggested that he do a scientific experiment, starting with making a testable hypothesis. Which of the choices below is a possible hypothesis for Arthur to investigate?
A. My house has more trees around it than any other house on our street.
B. Why do some leaves change colors, and others don't?
C. If I water the trees in my yard all winter, will they stay green until spring?
D. If I stop watering the trees in my yard early in the summertime, their leaves will change color before the neighbors' trees change.
3. Shakita wants to know if the pH of an open can of soda changes over time. To test this, she designs an experiment that will involve the following steps.
1.Open a can of soda and measure the pH.
2. Allow the open soda can to rest undisturbed on a level countertop at room temperature.
3. Measure the pH of the open soda can every day at the same time for ten consecutive days.
What is the dependent variable in Shakita's experiment?
A. the type of soda
B. the number of days
C. the pH of the soda
D. the temperature of the room
can you tell a science volunteer to help
I gave you the answer to 1 earlier.
Look in your text/notes for the others. Google the topics. You can find the answers to most of these with Google.
1. C. Ask the teacher about the proper place to dispose of the waste.
2. D. If I stop watering the trees in my yard early in the summertime, their leaves will change color before the neighbors' trees change.
3. C. the pH of the soda
1. Tommy should do option C and ask the teacher about the proper place to dispose of the waste. This is because sodium chloride is commonly used in experiments and can be considered hazardous waste. The teacher will have knowledge of the specific guidelines for disposal in the lab or school.
2. The possible hypothesis for Arthur to investigate is option D. If I stop watering the trees in my yard early in the summertime, their leaves will change color before the neighbors' trees change. This hypothesis suggests that withholding water from the trees in Arthur's yard may cause the leaves to change color earlier compared to the leaves of neighboring trees.
3. The dependent variable in Shakita's experiment is option C, the pH of the soda. This is the variable that will be measured and observed to determine if there are changes in the pH of the open can of soda over the course of ten consecutive days. The other options are independent variables or factors that are controlled in the experiment.