Applying the Scientific Method

Mrs. Melquist Name______Scientific Method Lab Set____ Date______Applying the Scientific Method

Objectives: - Develop a basic understanding of experimental design. - Observe and record data correctly. - Interpret the data generated. - Draw conclusions based upon the results of your investigation.

Background: Throughout the school year, you will be asked to conduct numerous scientific investigations. These investigations are essential to your understanding of what science is truly all about. Believe it or not, you have been using the steps of proper scientific investigation your whole life. You have observed the world around you. You have drawn conclusions based upon your observations. These conclusions have allowed you to from an explanation or hypothesis about everything that is in your world. If you don’t understand something, you ask questions or conduct investigations to figure out why things are the way they are. Scientists have created a very organized way of doing what we all do every day. They follow a series of exact steps in order to verify their results. These step-by-step investigations are called “experiments”. Every good experiment has the following: o A purpose – the reason for the investigation; o A hypothesis – what you believe the experiment will show; and o A procedure – exact steps to follow in order to conduct the experiment.

Every experiment has in it a control. The control is what the results of your experiment are compared to in order to determine what, if anything, occurred. Throughout the experiment you have to record all observations that you make. Qualitative (e.g. quality) observations are things like color and sounds. Quantitative (e.g. quantity) observations are measurements. Combined, these observations are called your “data”. Data are usually organized on tables, charts and graphs where it can be analyzed. Your analysis of the data will allow you to derive a conclusion that will either verify or nullify your original hypothesis. After the experiment is completed, further investigations following the same step-by-step scientific approach can be conducted.

Safety & Disposal: Be sure to keep your hands away from your face and mouth. Always wash your hands after completing the lab.

Activity 1: Effect of temperature on the emergence of sponge creatures

Purpose: In Activity 1, you will run an experiment to determine if different water temperatures effect the rate at which “sponge creatures” emerge from their gelatin chrysalis.

Hypothesis: Record what you think will happen on the “recording your observations” section.

Materials: 1 Cup, insulated Pen Thermometer 1 Sponge Creature 1 Stirrer, plastic 100mL Tap water (in a beaker) Procedure: 1. Mark your cup either 30C or 45C, whichever temperature you were given by your teacher for your group.

2. Observe the chrysalis of the “sponge creature”, and list 3 qualitative observations concerning it on the “recording your observations” section.

3. Pour approximately 100mL of water from the beaker containing the temperature range you were assigned, into your cup. Record the initial water temperature in Table 1.

4. One member of your team will be the timer. His job is to tell the other team member when to drop the “sponge creature” into the water sample. Using a timer with a second hand, you will measure how long it takes for the “sponge creature” to emerge from its chrysalis. When the timer says “go”, drop one of the “sponge creatures” into the water sample. Using the plastic stirrer, gently stir the water sample continuously. Stop the timer as soon as the “creature” emerges. Record the emergence time in Table 2.

5. Using a thermometer, measure the temperature of the water with the emerged “creature” in it. Record this measurement as the final temperature in Table 2.

6. Provide your results to your teacher to record on the blackboard. Graph the time it took for the sponge creatures to emerge using the bar graph provided in the “recording your observations” section. Answer the questions that follow.

7. Complete the conclusion section on the response page. Make sure that you include whether the results of your experiment verified your hypothesis.

Analysis:

Hypothesis: ______

Qualitative Observations: 1. ______

2. ______

3. ______Recording Observations:

Questions: 1. In the space below sum up what you have learned from this activity. Make sure you explain if your results were consistent with what you first outlined in your hypothesis. ______

2. Which sample took the longest to emerge? ______

3. What relationship can you explain in terms of sample temperature and the rate of emergence? ______4. Why was it important to make sure that the temperature remained constant throughout the investigation? ______

5. How long do you think it would take for the “creature” to emerge in boiling water? In ice water? ______

Activity 2: Effect of pH on the emergence of sponge creatures

Purpose: In this activity you will try to determine if pH has an effect on the rate of emergence of the “sponge creatures”.

Hypothesis: Record what you think will happen on the response page for Activity “B” at the end of this handout.

Safety: Goggles are required. You will be working with an acidic and a basic solution. The basic and acidic solutions can do damage to living tissue.

Materials: 1 Cup, insulated Pen 1 Sponge creature 1 Stirrer, plastic 1 Universal pH paper strip

Procedure: 1. Using a marker or pen, label one cup “basic” or “acidic” depending on what solution you were assigned by your teacher.

2. Observe the chrysalis of the “sponge creature” and list 3 qualitative observations concerning it on the “recording your observations” section. Also observe the appearance of the “acidic” and “basic” solutions.

3. Pour approximately 100mL of 30C acidic or basic water, whichever you were assigned, provided by your teacher, in your cup.

4. One member of your team will be the timer. His or her job is to tell the other team member when to drop the “sponge creature” into the water sample. Using a timer with a second hand, you will measure how long it takes for the “sponge creature” to emerge from its chrysalis. When the timer says “go”, drop one of the “sponge creatures” into the water sample. Using the plastic stirrer, gently stir the water sample continuously. Stop the timer as soon as the “creature” emerges. Record the emergence time in Table 3. 5. Using a pH paper test strip, measure the pH of the water with the emerged “creature” in it. Record the pH in table 2.

6. Provide your results to your teacher to record on the blackboard. Graph the time it took for the sponge creatures to emerge using the bar graph provided in the “recording your observations” section. Answer the questions that follow.

7. Complete the “conclusion” section on the response page. Make sure that you include if the results of your experiment verified your hypothesis.

Analysis:

Hypothesis: ______

Qualitative Observations: 1. ______

2. ______

3. ______

4. ______

5. ______

Recording Observations: Conclusion: 1. In the space below sum up what you have learned from this activity. Make sure you explain if your results were consistent with what you first outlined in your hypothesis.

______

2. Was pH a factor in the emergence of the sponge animals? ______

3. What would you use as a control in Activity 2? ______

4. Can you think of any other variables that you might test for their effect on emergence rate besides temperature and pH? ______

5. Examine the data collected by other classmates. Did the type of sponge animal or color have any effect on their rate of emergence? ______