How t o pl a n a nd c a r r y out i nv e s t i ga t i ons Scientists use investigations to find answers and solve problems. Graphic arranged by Newsela staff. Icons by GreenTana/ Getty Images. Scientific discoveries have the potential to change our lives, our communities and our understanding of the world. Very often, these discoveries are made during an investigation. This is a plan for asking questions and testing possible answers. So how do you plan and investigate something in science? Let's take a look. Decide Which Investigation You Want To Do There are three types of investigations. They all begin with a question about the world around you. A comparative investigation is one that uses a hypothesis and variables to determine a relationship. It does not need a control group. A descriptive investigation is one that is meant to answer a question or draw a conclusion about something. It does not need a hypothesis, variables or a control group. An experimental investigation is one that uses a hypothesis, variables and a control group to determine a relationship where one thing causes another. In the real world, scientists use all three types of investigations in their research. Diane Ragone is one example. She is a scientist at the National Tropical Botanical Garden in Kauai, Hawaii. She has By Alexa Kurzius, Newsela staff on 10.26.20 Word Count 735 Level MAXspent 30 years investigating breadfruit, a tropical fruit tree that grows in the hot, humid climates in tropical regions around the world. Breadfruit can be cooked like a potato, baked into bread, fried, pickled, added to soups and curries, and even made into desserts. A growing group of people, including Ragone, are working to make growing and eating the nutrient-rich food more popular. She has collected 150 breadfruit varieties (or types) around the world. She maintains 125 trees at the Botanical Garden with her staff. There are many types of investigations. Some involve conducting an experiment, while others focus on describing something. Either way, they all begin with asking a question about the world. Oftentimes, this is followed by making a hypothesis and considering different variables. Use Fair Tests And Controlled Variables As mentioned above, some investigations require a hypothesis, variables or a control group. A hypothesis is a tentative answer to a scientific question that can be answered. There are two types of variables: an independent variable and a dependent variable. The independent variable is one that the scientist changes during the experiment to see how it impacts the dependent variables. The dependent variable is one that depends on other factors in anexperiment (such as the independent variable). A control group is a group in an experiment in which scientists do not change the independent variable. In most experiments, a control group is set up with the same conditions as another group, in which the independent variable is changed. This allows researchers to compare the results from the two groups. When conducting an investigation, it's important for them to be a fair test, which means just one variable is changed at a time. You will also want to decide how many times you conduct your test. It is recommended that you do your investigation at least three times, though the more times you do your test the better. This helps you better make sure that your results are not random, or due to chance. Last, you'll want to determine what kind of measurements you need to take (and which tools to use in these measurements) during the investigation. Make Observations, Take Measurements And Make Predictions Once you decide on the investigation you want to do, you can go ahead and do it. This includes observing what you notice ishappening, and writing those observations down. You will also likely want to take measurements so you have precise data to analyze and interpret later. It's possible that things may change during your investigation and that the outcome ends up being different than what you expected. That's why it is helpful to make predictions for what you think This article is available at 5 reading levels at https:/ / newsela.com. might happen, so that you can be prepared and make changes, or adjustments if need be. You'll also want to write down those changes so the people you share the results with know what you changed. Once you have gathered all of your data, you'll want to make sense of it to help create a scientific explanation that is informed by evidence. To learn more on how to do this, check out this article on how to analyze and interpret data

Quiz 1 Which sentence from the section "Use Fair Tests And Controlled Variables" BEST introduces independent variables to the reader? (A) As mentioned above, some investigations require a hypothesis, variables or a control group. (B) There are two types of variables: an independent variable and a dependent variable. (C) The dependent variable is one that depends on other factors in an experiment (such as the independent variable). (D) In most experiments, a control group is set up with the same conditions as another group, in which the independent variable is changed. 2 How effective is the introduction [paragraphs 1-2] at introducing the idea of scientific investigations? (A) It is effective because it provides an overview of the steps in a scientific investigation. (B) It is effective because it emphasizes the benefits of scientific investigations. (C) It is ineffective because it only describes the importance of comparative investigations. (D) It is ineffective because it brings into question the relevance of descriptive investigations. 3 Read the section "Decide Which Investigation You Want To Do." What does this section show that other sections do not? (A) It shows a real-world example of a scientist who conducted scientific investigations. (B) It shows why experts believe scientific investigations should be conducted. (C) It shows the importance of different types of variables in scientific investigations. (D) It shows why scientific investigations require predictions to be made.How does the author build understanding of control groups? (A) by explaining the pros and cons of using control groups in investigations (B) by comparing control groups with other groups used in experiments (C) by detailing how observations affect the conditions of control groups (D) by providing anecdotes showing how control groups are used