Experimenting with Science. Mullins Olivia J.

sometimes it‘s really tough! Either way, science is for all kids, and the experiments in this book are for you.

      WHAT YOU NEED TO KNOW

      One thing you need to know for many experiments in this book is how to make measurements. If you’re unsure how to measure out things like 8 inches or ½ tablespoon, it’s no problem – just find an adult to help you out with this part.

      ABOUT THE ICONS

      As you read through the projects in this book, you’ll see a few icons. The icons point out different things:

      

This icon points out tips that can make your experiments run more smoothly.

      

This icon alerts you to information that you’ll want to remember.

      

Pay attention to the warnings! They contain safety information or instructions on how to perform an experiment without damaging anything in your house (like keeping magnets away from computers). Some warnings are used to prevent something that may ruin the actual experiment.

      PROJECT 1

      THE FORCES AROUND YOU

       IN THIS CHAPTER, YOU LEARN ABOUT FORCES. You play with magnets, move stuff with static electricity, swing water over your head while staying dry, and defy gravity with a string of beads.

      WHAT IS A FORCE?

      The experiments in this chapter all have something in common: they all explore forces.

      So what is a force? The definition of a force is simple; it is a push or a pull on an object. If you have an object in front of you, push it across the table. You just applied a force to an object. Now pull it back toward you. Another force!

      Every force has a direction. To show this direction, scientists draw arrows. If you push an object away from you (like a chair), the direction of that force is away from you. If you pull the object toward you, the direction of the force is toward you.

      Forces can be big or small. If you push on something lightly, it is a small force. If you push harder, that force is bigger.

      Forces can make things move, or make things move faster, or make moving things stop or change direction. Imagine hitting a baseball that has been pitched to you. The forces from your arms and the bat cause the ball flying through the air to change direction and to go at a different speed. Sometimes you can apply a force to something that is not moving and the object will … continue not to move! Imagine pushing against a wall; you are applying a force to the wall, but unless you are the Hulk the wall will remain motionless.

      You may think that if something isn’t moving that no forces are acting on it, but this is not true. Forces are all around you, and forces are always, at every moment, acting upon you! The biggest example of this is that everything on earth is being pulled down at all times by the force of gravity.

      You can’t see gravity, but it is still a force. Gravity acts at a distance, and you could even consider gravity an invisible force. Other invisible forces include magnetic and electrical forces. For electrical forces, think of plugging in a fan. You can plug it in and turn it on, and electricity provides the force needed to move the fan blades.

      One last rule that’s good to know is that a moving object will continue to move in the same direction, and at the same speed, until another force acts on it. This is called inertia. At first, this rule may not seem to make sense because if you throw a ball, it will not stay in the air forever. But don’t forget that the force of gravity is acting on the ball, pulling it down. Even the air itself acts as a force that slows the ball down!