Hypotheses Variables 6 th Grade Science Hypothesis A

Hypotheses & Variables 6 th Grade Science

Hypothesis • A prediction that links a cause to an effect. • Testable • Based on prior knowledge or observations • Example: If the average daily temperature drops in the fall, then the leaves will change colors.

Variables • 1) Controlled Variables variable that could change but are not allowed to. ▫ Stays the same through all phases of the experiment. ▫ Allows the experiment to be a fair test.

Variables (continued) • 2) Independent Variable ▫ ▫ The one variable that is being changed. What is being tested. Causes the change in the dependent variable. Also known as the manipulated variable.

Variables (continued) • • • Dependent Variable that is being measured or observed. The data that is collected. The ‘effect’ of the independent variable. Also known as responding variable.

Control Group • Group that is not tested. • Used to compare results.

Reliable Experiments • Reliable experiments have been repeated numerous times. • This shows if the data is accurate and consistent.

Writing a Hypothesis • “If…. , then…” statements. • If independent variable, then dependent variable.

Examples • Chocolate may cause pimples. • Salt in soil may affect plant growth. • Ultraviolet light may cause skin cancer. • Temperature may cause leaves to change color.

All of these are examples of hypotheses because they use the tentative word “may. ” However, their form is not particularly useful. Using the word “may” does not suggest how you would go about proving it. If these statements had not been written carefully, they may not have even been hypotheses at all. Formalized hypotheses contain two variables. One is independent and the other is dependent. The independent variable is the one that you observe and/or measure the results.

Practice • Will teens grow more if they drink milk? • When sticky candy is eaten frequently, do more cavities develop? • Will poor eyesight result from using the computer too often? • Will test scores increase if studying is done frequently?

More… • Students of different ages were given the same jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

• Identify the variables in this investigation.

What was the independent variable? What was the dependent variable?

What was a controlled variable?

Another Example • The higher the temperature of water, the faster an egg will boil.

• Independent variable? • Dependent variable ? • Controlled variable ?