 Today we are going to be building a rubber band toy car. It's quick, fun, and easy to build. It will take approximately 20 minutes. In this video, I will first teach you guys how to build a toy car. And then I'm going to talk a little bit about the science concepts related to this car. We're going to learn a little bit about Newton's first law and friction. To build this toy car, you will need three popsicle sticks, two kebab skewers, a paper clip, one straw, a pair of scissors, a small rubber band, a hot glue gun, and finally four bottle caps and something pointy to poke the bottle caps with. Start off by taking two popsicle sticks and form a skinny triangle with them. Now take your straw and scissors and cut off one small piece and another longer piece. Now take your hot glue and glue on the two straws. Now cut off the sides of the straw. Cut off a small piece from your third popsicle stick. Get your rubber band and paper clip and attach the rubber band to the paper clip and attach the paper clip to the popsicle stick. Now hot glue the popsicle stick onto the body of your car. Now it's time to poke some holes through our bottle caps. Take your sharp object and poke one bottle cap through from the top. Make sure that you're poking through it straight. This is very important. Poke a second bottle cap from the top also and for your third and fourth bottle caps, poke them from the other side. Now take one of your skewers and a bottle cap that you poke through from the bottom and slide the cap onto the end of the skewer. Make sure that you slide the cap on straight so your car can roll straight. Now slide your skewer through the straw. Now take a bottle cap that you poked through from the top and slide that onto the skewer. Repeat these same steps. Now cut off any parts that are sticking out except leave one side so you can use that to help you spin the wheels back later. Now taking one of the skewers that you cut off earlier, cut off about half an inch. Hot glue it onto the back skewer. The car is now done. Let's test it out by pulling the ribbon back, attaching it on the stick, and now we're going to spin the stick back. Did you guys see that? The reason why our car's wheels are spinning but the car itself is not actually moving forward is due to friction. Friction is the force exerted by a surface when an object moves across it. In other words, friction is the force that opposes the motion of an object. The caps themselves have friction but there is not enough friction for the car to be moving forward and you might think why don't we decrease the amount of friction so there's less force opposing the motion of the car but in this case we actually want more friction than the friction the caps themselves provide. So adding more friction to the caps is the solution to our problem. One way we can add more friction is by adding a thin layer of hot glue around the back wheels of our car. Since the rubber band is spinning the back wheels only we want the back wheels to have more friction so they can grip onto the surface and push the car forward. Compare that to before we added the hot glue that was a big difference. Now let's learn about Newell's first law. His first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. In this case the external force is the rubber band. The rubber band wants to go back to its original shape. As a result it will spin the stick which in turn spins the back wheels. With no force such as the rubber band you can clearly see that the car is not moving it's staying still and once we spin the rubber band around the back stick then the car will move forward. Now his law does say that every object will remain in uniform motion unless compelled to change its state by an external force. So what makes our car stop moving? Well the answer is friction. Like I said earlier friction is the force that opposes the motion of an object. So as the car moves one direction the force of friction is acting against it therefore the car slowly goes to a halt. Now that we've learned how to build the car we've learned about friction and Newell's first law. While you go and experiment find different surfaces around and in your house and compare the distances the car travels. See how friction affects the distance the car is able to travel.