Scientific Method

Section Summary Science is the investigation and exploration of natural events and of the new information that results from those investigations. People use science in their everyday lives and careers. Examples include firefighters wearing heat resistant clothing, parents setting up fish tanks, athletes using their speed to increase momentum, and you deciding what to eat so that you’ll feel energetic and healthy. When scientists conduct scientific investigations they use scientific inquiry. Scientific inquiry is a process that uses a set of skills to answer questions or to test ideas about the natural world. The series of steps used in each investigation often varies but there are general practices that every good scientist uses. The scientific method (outlined below) is a systematic way scientists try to solve problems. It is not always followed precisely as unexpected events may occur, but it is a universal procedure that has been used since the 17th century. Anyone can begin a scientific inquiry by observing the natural world and asking questions. Observation is the act of using one or more of your senses to gather information and taking note of what occurs. Inferences are made as a result of observations. An inference is a logical explanation of an observation that is drawn from prior knowledge or experience. For example you might observe that a plant is wilted and you’d likely infer that the plant is lacking water. With further investigation a scientist performs research and develops a hypothesis with a method to test it. A hypothesis is a possible explanation for an observation that can be tested by scientific investigations. Testing a hypothesis can be done in several ways that often include experimentation and models. The things that are changing in an experiment are called variables. An experiment usually has three kinds of variables: independent, dependent, and controlled. The independent variable is the part we manipulate. The dependent variable changes as a result of the independent variable. The controlled variable is held constant and used for comparison. This is necessary to validate results. These variables are usually organized in a chart and data is often collected and recorded with tables and graphs. Data analysis allows scientists to draw conclusions. A conclusion is a summary of the information gained from testing a hypothesis. The results and conclusions from an investigation can lead to many outcomes, such as the answers to a question, more information on a specific topic, or support for a hypothesis or theory. A scientific theory is an explanation of observations or events that is based on knowledge gained from many observations and investigations. A scientific theory is generally accepted as true until it is disproved. An example of a scientific theory is the theory of plate tectonics which explains how Earth’s crust moves and why earthquakes and volcanoes occur. Read the passage. Match each number with the step of the scientific method that corresponds with the numbers in the passage.Daniel notices that most coffee shops seem to use paper cups to sell coffee1. He hypothesizes that paper cups keep coffee warmer than Styrofoam cups for a longer period of time2. He designs an experiment with a paper cup and a Styrofoam cup in which he places one cup of hot water in each3 and records the temperature every 5 minutes for 30 minutes4. His results show that Styrofoam actually keeps the water warmer for a longer period of time5. He decides to do the experiment again and compare with metal reusable coffee mugs6. 1 observation 2 hypothesis 3 experiment 4 data 5 conclusion 6 repeat Which two things should be held constant in Daniel's experiment described above? temperature of the water and type of cup temperature of the water and size of the cup location of the cup and amount of water used amount of water used and type of cup Identify each part of Daniel’s experiment explained above by matching the letter with the appropriate term. control styrofoam cup used for comparison independent variable type of cup dependent variable change in temperature The data table to the below shows the yield of vegetables in a school’s garden for three years. The yield is the number of pounds of vegetables harvested. The same number of each type of vegetable was planted every year.Which statement is an inference? The onion yield was greater than the beet yield in 2013. The butternut squash yield increased from 2011to 2012. The spinach yield was 102 pounds in 2011 and 137pounds in 2012. The acorn squash yield decreased from 2012 to 2013due to lower temperatures.