**Science Process Skills** Inferences, Variables, Predictions, Hypothesis, and Research Questions Science Middle School Teacher Page

**Return to** The Whole Thing Return to Activity Inferences • An inference is an explanation for what we have observed. It explains what might be happening. • An inference must be logical. • Inferences can be changed as you get more information. Science Process Skills

**You Try It!** You come into the classroom and you observe someone’s books are at your desk. What inference can you make? Why would “The student was abducted by aliens.” not be a good inference? Because it is not logical. Science Process Skills

**Return to ** The Whole Thing Return to Activity Variables • The part that changes in an experiment. • Independent variable is what the scientist changes. There is only 1 of these. • Dependent variable is the difference the scientist measures after making the change. There is only 1 of these. • Constant variables are what the scientist makes sure stays the same so the experiment is a fair test. There are many of these. Science Process Skills

**You Try It!** Rachel counted the leaves on each of three plants. Then she put one plant under a blue light bulb, another plant under a yellow light bulb, and a third plant under a white light bulb. She kept all three lights on from 6:00 a.m. to 9:00 p.m. After 2 months, she counted how many leaves each plant had. Name the independent variable, the dependent variable and 3 constant variables? Science Process Skills

**Check Your Answers** • The independent variable is the color of the light. • The dependent variable is the number of leaves on the plant. • Some constant variables are: the same kind of plant, the same soil, the same amount of water, the same size pot, the same temperature, the same wattage of light bulb, the same distance away from the light bulb. Science Process Skills

**Predictions** • A forecast of future events. • Based on your observations. • Based on cause and effect relationships (since this happened, then this will happen). • Should be more accurate as you get more information. Science Process Skills

**Return to** The Whole Thing Hypothesis • A special prediction that forecasts how the independent variable will affect the dependent variable. • If the independent variable(increases/decreases), then the dependent variable will (increase/decrease). Science Process Skills

**You Try It!** Write a hypothesis for the following experiment: Juan wants to know if the size of the paper airplane’s wings will change the distance that the plane will fly. First, identify the independent variable. Science Process Skills

**Juan wants to know if the size of the paper airplane’s** wings will change the distance that the plane will fly. The independent variable is the size of the paper airplane’s wings. Now identify the dependent variable. Science Process Skills

**Juan wants to know if the size of the paper airplane’s** wings will change the distance that the plane will fly. The independent variable is the size of the paper airplane’s wings. The dependent variable is the distance the plane will fly. Write your hypothesis. Science Process Skills

**Juan wants to know if the size of the paper airplane’s** wings will change the distance that the plane will fly. The independent variable is the size of the paper airplane’s wings. The dependent variable is the distance the plane will fly. If the ____________________________ (increases/decreases), then the ____________________ will increase/decrease). size of the paper airplane’s wings distance the plane flies

**Return to ** The Whole Thing Research Questions • Can not be answered with a yes or no. • Has a question mark at the end. How does the independent variable affect the dependent variable? Science Process Skills

**You Try It!** • Write a research question for the following experiment: Toni puts salt, cat litter, and alcohol on ice and measures how much the ice melts in 30 minutes. First, identify the independent variable. Science Process Skills

**Toni puts salt, cat litter, and alcohol on ice and measures** how much the ice melts in 30 minutes. The independent variable is the substance put on the ice. Next, identify the dependent variable. Science Process Skills

**Toni puts salt, cat litter, and alcohol on ice and measures** how much the ice melts in 30 minutes. The independent variable is the substance put on the ice. The dependent variable is how much ice melts. Now write your research question. Science Process Skills

**Toni puts salt, cat litter, and alcohol on ice and measures** how much the ice melts in 30 minutes. The independent variable is the substance put on the ice. The dependent variable is how much ice melts. How does _________________________ affect ___________________? the substance put on the ice how much ice melts Science Process Skills

**Inference** Variables The Whole Thing You observe that a penny will hold 47 drops of water, and a quarter will hold 92 drops of water. • Using your observation, what inference can you make? • Using your inference, what will your independent variable be? • What will your dependent variable be? Science Process Skills

**Hypothesis** Research Question Variables The Whole Thing You observe that a penny will hold 47 drops of water, and a quarter will hold 92 drops of water. 4. Name 2 constant variables. 5. Write your hypothesis. 6. Write your research question. Science Process Skills