< PreviousMy mom and I are visiting with our neighbor Mrs. Howard and her son Tredell. Tredell and I want to play with his toy cars, but the WHEEL and AXLE broke on one of them. 6The AXLE goes through the middle of the WHEEL, and the wheel and axle turn together to move things. A wheelbarrow has one wheel and axle. A tractor trailer can have as many as nine axles and eighteen wheels. Axle Wheel A WHEEL and AXLE is a type of simple machine that helps move things like cars, wagons, and wheelbarrows. 7Instead of playing with toy cars, Tredell and I decide to make paper snowflakes out of colorful paper. We first fold the paper and then use scissors to cut out small shapes. 8A LEVER is a rod or a bar that pivots at a point called the fulcrum. The fulcrum can be in the middle of the lever or at the end of the lever. Scissors are made of two levers with a fulcrum that joins them together in the middle. lever Scissors are a type of LEVER, which is a simple machine. 9Later on, I meet my friend Jack down at the playground behind our apartment building. My favorite thing at the playground is the seesaw. Jack loves it, too! 10The ends of the seesaw move up and down because the seesaw is another type of LEVER—one that has a fulcrum in the middle. When the weight on both sides of the LEVER is the same, the lever stays level, or is balanced. When more weight is put on one side, that side goes down and the other side goes up. A balance scale is an another example of this type of lever. lever 1112 On my way back inside, I meet Ms. Jacqueline. She’s moving into our building today. She has a lot of boxes to move! Ms. Jacqueline moves her boxes off of the moving truck by walking them down the ramp. If she couldn’t use the ramp to unload her boxes, she would have to climb in and out of the truck with every box. That would take a long time!A ramp is a type of simple machine called an INCLINED PLANE. An inclined plane is a flat surface that is higher on one end. There are different types of inclined planes. Ramps, ladders, and playground slides are all examples of inclined planes. inclined plane 13Mr. Perron is the handyman in our building. He stops by to fix the knob on our door. I ask if I can help, too. Mr. Perron uses a screwdriver to put a new doorknob on our door and uses SCREWS to hold it in place. 14A SCREW is a type of simple machine that is used to hold things together. Screws have threads around them that keep them securely in place. The top of a SCREW is called the head. A screwdriver fits perfectly into the notch on the head of a screw so you can turn it and tighten it into place. screw 15Next >