California science grade 3 (5)

Investigate and Experiment The name of this fossil, Archaeopteryx, means “ancient wing.” What Is Science? Science is a way of understanding the world around us Scientists often ask questions about what they observe They call on many skills to help them answer these questions This process of asking and answering questions in science is called inquiry In this section, you will see how scientists use inquiry skills to learn about dinosaurs Investigation and Experimentation Scientific progress is made by asking meaningful questions and conducting careful investigations As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations Students will: a Repeat observations to improve accuracy and know that the results of similar scientific investigations seldom turn out exactly the same because of differences in the things being investigated, methods being used, or uncertainty in the observation b Differentiate evidence from opinion and know that scientists not rely on claims or conclusions unless they are backed by observations that can be confirmed Inquiry Skills These are the inquiry skills scientists use You can use these skills, too Observe Infer Compare Classify Measure Use Numbers Communicate Predict Record Data Analyze Data Form a Hypothesis Use Variables Experiment Make a Model c Use numerical data in describing and comparing objects, events, and measurements d Predict the outcome of a simple investigation and compare the outcome with the prediction e Collect data in an investigation and analyze those data to develop a logical conclusion Observation > Are you an observant person? You might look out the window to see if it is raining You might even listen for rain on the windowsill You make observations throughout your day Observations of the world around us often raise questions The diagram on this page shows processes that scientists use to answer questions Many call this the “scientific method.” Scientists don’t always use all of the steps They may not use them in the same order Inquiry Skills When you make observations, you use these skills Observe Use your senses to learn about an object or event Classify Place things that share properties together in groups Measure Find the size, distance, time, volume, area, mass, weight, or temperature of an object or an event Question and Hypothesis > Do you ask “why” questions when you are curious about things? The work of scientists often starts with an unanswered question Scientists then suggest a possible answer that can be tested with an experiment This is known as forming a hypothesis A good hypothesis must ▸ be based on what you observe ▸ be testable by doing an experiment ▸ be useful in predicting new findings Which of these dinosaurs was a meat eater and which was a plant eater? Form a hypothesis to answer this question Inquiry Skills A scientific hypothesis must be testable That means you must be able to support or disprove your hypothesis by experimenting When you experiment you a hands-on activity to test an idea Scientists often research before they experiment They look in books, scientific journals, or Internet resources for information that other scientists have found Scientists also know that they cannot rely on someone’s opinion or claim unless it has been backed up by observations When you ask questions and form hypotheses, you use these skills Infer Form an idea from facts or observations Form a hypothesis Make a statement that can be tested to answer a question 3.IE.5.b Differentiate evidence from opinion and know that scientists not rely on claims or conclusions unless they are backed by observations that can be confirmed Now it’s time to test your hypothesis with an experiment In experiments you change one variable to see what happens with another variable For example, you might make a model to find out how the type of soil affects the shape of a dinosaur’s footprint What would happen if you changed both the type of soil and the size of the dinosaur? Experiments must be able to be repeated, too This allows scientists to evaluate and compare each other’s work They can check their own work too! So a good experiment must: ▸ change only one variable at a time ▸ be able to be repeated Experiment > Inquiry Skills Before you test a hypothesis, you must have a plan When scientists make a plan, they think about the variables they want to test A variable is something that can be changed or controlled It is important to change or control only one variable at a time Keep all other parts of the experiment the same That way you will know what caused your results After they determine their variables, scientists decide what materials they will need Then they write a procedure A procedure is a series of numbered steps that tell what to first, next, and last After scientists have developed their procedure, they predict what will happen when they follow it To predict means to tell what you think will happen When you experiment, you use these skills Experiment Perform a test to support or disprove a hypothesis Use variables Identify things in an experiment that can be changed or controlled Predict State possible results of an event or experiment Make a model Make something to represent an object or event What’s one important part of a science experiment? Collecting and recording good data! When data are collected they may then be explained, or interpreted Collecting and interpreting data often requires working with numbers This scientist will measure and record the length and weight of the dinosaur fossil she is studying 10 Collecting Data > Inquiry Skills When scientists follow their procedure, they make observations and record data Data is information Measurements are a type of data Scientists use measurements whenever they can to describe objects and events Scientists measure such things as length, volume, mass, temperature, and time Scientists repeat their procedure several times This helps them know if their results are correct They often compare their results with other scientists Other scientists will repeat the procedure to see if they get the same results When you collect and interpret data, you use these skills Use Numbers Order, count, add, subtract, multiply, and divide to explain data Measure Find the size, distance, time, volume, area, mass, weight, or temperature of an object or an event Record Data Accurately arrange and store information collected in science investigations Analyze Data Use the information that has been gathered to answer questions or solve a problem 11 You’ve collected and interpreted data Now what? It is time to draw a conclusion A conclusion states whether your data support your hypothesis But what if your data not support your hypothesis? Perhaps different experiments are needed Perhaps a new question will result Scientists also share with others what they have found This allows scientists around the world to stay informed And it allows scientists to check each other’s work Scientists also share what they have learned with the public Have you ever been to a museum with displays of dinosaur fossils like this? 12 Conclusion Inquiry Skills Scientists organize and analyze their data to see if the results support or disprove their hypothesis They determine if their prediction matched their results They draw conclusions and try to explain their results When you draw conclusions you interpret observations to answer questions When you draw conclusions and communicate results, you use this skill Communicate Share information Sometimes the results of an experiment lead to new questions These questions can be used to form a new hypothesis and perform new tests The process starts all over again This process of asking and answering questions is called the scientific method 13 Forming a Hypothesis Now it’s your turn to be a scientist and design a good experiment Most science experiments start with an unanswered question Students wondered how dinosaur footsteps could show how large the animal was This was their question: Question • Does the length of your leg affect the distance between your footsteps? The students turned the question into a statement that can be tested This is called a hypothesis A hypothesis is an “if… then…” statement Hypothesis If the leg is longer, then the distance between the footsteps will be greater 14 Defining Variables Make a plan to test the hypothesis The first step is to identify what is being tested and what is not being tested These are called your variables Controlled variables are not being tested These variables remain constant during an experiment In this experiment the controlled variables will be: • The walking pace for each student tested • The location of the test • The starting point for the test The only thing that will change is the factor you are testing This is the independent variable Your independent variables will be the length of the leg of each student tested The dependent variable is what you are measuring In this experiment the dependent variable is the distance between the footsteps 15 Designing an Experiment Design an experiment to test the hypothesis Here is an experiment a group of students designed to test this hypothesis Procedure Choose three classmates with different lengths of leg Measure the length from the waist to the ground Record each length Predict Which student will have the longest footstep? Measure a meter piece of butcher paper Mark a START line at one end of the paper Have students take normal steps from the START line Measure each footstep from heel to heel Record your measurements in a data chart Repeat the experiment to verify your results Was your prediction correct? 16 Analyzing Data In order to communicate the results of an experiment the data need to be presented in a clear way These students used the data chart to make a bar graph that shows how the length of the leg relates to the length of the footstep Does this graph help others understand the results of the experiment? Why is it important to repeat experiments? IE 5.a Repeat observations to improve accuracy and know that the results of similar scientific investigations seldom turn out exactly the same because of differences in the things being investigated, methods being used, or uncertainty in the observation • IE 5.c Use numerical data in describing and comparing objects, events, and measurements • IE 5.d Predict the outcome of a simple investigation and compare the outcome with the prediction • IE 5.e Collect data in an investigation and analyze those data to develop a logical conclusion 17 Forming New Questions It is important to repeat experiments Why is this so? Science experiments produce new ideas New questions may arise After reading the results of this experiment, other students wrote down the following questions they were interested in studying The exciting thing about science experiments is that they can cause new questions to arise For example: • What if you compared an adult and a student? • What if you used an inclined plane instead of a flat surface? • What if you compared running footsteps? Write a hypothesis for one of these questions or one of your own Talk about it with your class Work together to write a plan to test this new hypothesis 18 ...What Is Science? Science is a way of understanding the world around us Scientists often ask questions about... answering questions is called the scientific method 13 Forming a Hypothesis Now it’s your turn to be a scientist and design a good experiment Most science experiments start with an unanswered question... facts or observations Form a hypothesis Make a statement that can be tested to answer a question 3. IE.5.b Differentiate evidence from opinion and know that scientists not rely on claims or conclusions