Scientific Method
A scientific method is: a systematic approach used to answer a question or study a situation. both an organized method for scientists to do research and a method for scientists to verify the work of other scientists. includes making observations, stating a problem, forming a hypothesis, performing an experiment, and arriving at a conclusion.
Problem The problem should be stated as a question.
1. What question is being asked? a. How much mechanical energy does the battery produce? b. How much pressure is created by an electric current? c. What is the pH of water during electrolysis? d. How much energy is converted to heat?
1. What question is being asked? a. How much mechanical energy does the battery produce? b. How much pressure is created by an electric current? c. What is the pH of water during electrolysis? d. How much energy is converted to heat?
2. The table shows times required for water to evaporate from identical containers. Which of these is the best question to ask before developing a reasonable hypothesis to explain the data? A. Why does a lower temperature slow the rate of evaporation? B. Why does water exist as a solid at -15C and as a liquid at 25C? C. What is the boiling point of the water after both samples are heated? D. How does the rate of evaporation change when a different container is used?
2. The table shows times required for water to evaporate from identical containers. Which of these is the best question to ask before developing a reasonable hypothesis to explain the data? A. Why does a lower temperature slow the rate of evaporation? B. Why does water exist as a solid at -15C and as a liquid at 25C? C. What is the boiling point of the water after both samples are heated? D. How does the rate of evaporation change when a different container is used?
Hypothesis The hypothesis is the answer to the problem and must be stated in a way that can be tested by an experiment.
DRY MIX Independent Variable - The variable that is changed on purpose by the experimenter. It is sometimes called the manipulated variable. This is the “if” part of a hypothesis; plotted on the “x” axis. Dependent Variable - The variable that acts in response to the manipulation of the independent variable. It is sometimes called the responding variable ; plotted on the “y” axis.
Controlled Variables Controlled variables-Any other variable which might affect the value of the dependent value and is held constant.
3. Students placed equal amounts of bread mold on 12 identical agar plates containing the same amounts and types of nutrients. Four plates were kept at 0°C, four were kept at 45°C, and four were kept at 22°C (room temperature). The plates were examined after five days. Which of the following was probably the hypothesis for this experiment? The growth of bread mold increases as temperature increases. The size of the plates determines the temperature of bread mold. The type of nutrient causes bread mold to grow faster at higher temperatures. The temperature of bread mold is determined by the mold’s growth.
3. Students placed equal amounts of bread mold on 12 identical agar plates containing the same amounts and types of nutrients. Four plates were kept at 0°C, four were kept at 45°C, and four were kept at 22°C (room temperature). The plates were examined after five days. Which of the following was probably the hypothesis for this experiment? The growth of bread mold increases as temperature increases. The size of the plates determines the temperature of bread mold. The type of nutrient causes bread mold to grow faster at higher temperatures. The temperature of bread mold is determined by the mold’s growth.
Valid Experiment When an experiment is conducted with one (and only one) independent variable and one (and only one) dependent variable while holding all other variables constant
Valid Experiment To test your hypothesis make a step-by-step procedure of what you will do Select only one variable to change in each experiment (independent variable). Change a variable that will help you test your hypothesis. The procedure must tell HOW you will change this variable. The procedure must explain how you will measure the amount of change. The procedure should indicate how many trials would be performed
Observation vs Inference Observation: Information obtained through the senses: sight, touch, smell, etc; often involves a measurement Sight Touch Smell Hear Inference: a conclusion based on the data collected
4. A valid study would include a control group containing — a. bean seed, tomato seed, sunflower seed, and water b. water only c. water and 2% root hormone d. bean seed, tomato seed, sunflower seed, water, and 1% root hormone
4. A valid study would include a control group containing — a. bean seed, tomato seed, sunflower seed, and water b. water only c. water and 2% root hormone d. bean seed, tomato seed, sunflower seed, water, and 1% root hormone
CONCLUSION Using the trends in the experimental data and observations, try to address your hypothesis. Is your hypothesis correct? It is now time to pull it all together and assess the experiment you did.
5. Which of the following conclusions is supported by the information below? a. Antibiotics have intensified the symptoms of M. tuberculosis infections. b. Antibiotics have caused M. tuberculosis to reproduce at a faster rate. c. M. tuberculosis is becoming extinct because of antibiotics. d. M. tuberculosis has developed resistance to antibiotics.
5. Which of the following conclusions is supported by the information below? a. Antibiotics have intensified the symptoms of M. tuberculosis infections. b. Antibiotics have caused M. tuberculosis to reproduce at a faster rate. c. M. tuberculosis is becoming extinct because of antibiotics. d. M. tuberculosis has developed resistance to antibiotics.
Theory Formed from a set of related hypotheses that have been tested and supported by many scientific investigations. Allows us to make predictions Events predicted by repeat without variation Explain the causes of observations that we make.