Whenever two things rub together, some of the energy they have is lost to friction. Basically, in things like car engines, the wheels of your skates, and the chain of your bike, friction is a force that slows you down. In order to overcome friction, you have to work harder. However, the energy doesn't just disappear ó it's turned into heat! Try rubbing your hands together as fast as you can. Pretty soon, they'll be burning up!

As it turns out, the rougher two surfaces are, the more friction there is between them when they rub together. By making things really smooth, or by adding lubricants like grease and oil, engineers work hard to reduce friction and in the long run, save energy.

Friction isn't always bad though. If you've ever tried to start running on a wet floor, you know that too little friction can just make you slip and slide. You need a certain amount of friction to get a grip in order to get yourself going. That's why winter car tires usually have deeper treads than regular tires. The extra grooves make the surface rougher and help them get a grip on ice and snow. Ever wonder why sneakers always have treads on the bottom? They're there to give you some extra grip when you run and play.

Now that we've got you thinking about the force that makes you grip and slip, it's time to observe and record. 

Our shoes and the surface we are walking on are rubbing together. It could be a rug, polished brick, or a floor made of tile. Well, if we are walking on the rug it kind of slows us up. If I want to walk faster, friction makes it harder. Well, I think if I'm walking on a rug there's nothing I can do to reduce friction, but if I'm on a tile floor I can polish it. This will make it great to slide on, wearing only socks!!!! But if I'm barefoot, the polishing will not make that much difference. If I have shoes like sneakers then it will be harder. Our sneakers will sound like cars when they burn rubber. Rollerblading on a rug!!!! you definitely have to work harder!!!

The two things that are rubbing together are the plate and the sponge. In this case, friction helps by removing dirt from the plate. To increase the friction, you get a good sponge with a rough surface. Friction is similar when you are washing a car.

The tip of your pencil and the paper are rubbing together. Friction is helping you get something done. It rubs off lead particles, which makes your writing or your picture visible. You can decrease the amount of friction by sharpening your pencil. This lessens the amount of one of the two rubbing surfaces. When you write with chalk on a chalk-board, the rough surface rubs off chalk particles making your picture or your writing visible.

When youíre drawing on the chalkboard, the two things that are rubbing together are the chalk and the chalkboard. Friction is helping you to write. Write harder so there is more friction. Drawing on a piece of paper is a similar case to drawing on a chalkboard.

When you're brushing your teeth, the two things rubbing together are the brush bristles and your teeth. Friction is helpful while brushing. It allows you to clean your teeth. Sometimes the friction is bad because it can hurt your loose tooth when you're brushing it. Also, if you brush too hard, and there's too much friction, it can hurt. To make your teeth cleaner, brush harder or longer. To keep the brushing from hurting, reduce the friction by brushing more gently. Similarly, if you brush your hair, it's good for you. If you brush too hard, it could hurt you. Scrubbing helps clean, but scrubbing too hard can damage an object. Friction can be helpful, but too much can be harmful.