How do you know the results of your experiment will be correct? Scientists carefully plan each step of their investigation so their results will be reliable. Different questions require different kinds of investigations. Learn how to plan your own investigations based on fair tests. The Science Sleuths series encourages you to think and act like a scientist. Each book explores an important skill in scientific exploration. Questions and activities help you look at the world around you in a curious way-the scientific way! Book jacket.