Science Sunday/Friction and Inertia

One of Selena’s favorite shows is Sid the Science Kid. She picks up concepts and talks about them a lot but I often wonder if she truly understands what she is seeing from the show let alone what she tends to talk about. The episode she watched on Friday was about friction. One thing that Selena did make a comparison on was how slick the floor is at dance class compared to our carpet. Sometimes I guess she does learn more then we think. I decided to do some exploring with this idea of Friction.

I took one of our bath mats which is rough, a pillow case which is a little smoother, then the top of our table which has a slick finish on it. I wanted Selena to compare two different objects, the first was a flat wooden shape piece, the other a sturdy plastic lid that was not as smooth.

We first slid our pieces across the smooth table to discover they went pretty far, depending on how much force Selena gave them. We also took this time to discuss force, she gently pushed the piece then gave it a good strong push.

The first observation Selena made was that the wooden smooth piece when further then the plastic rougher lid.

We then compared how the pillow case felt compared to the table top. Selena described it as smooth, but not as smooth as the table. She then tried to slide the pieces across the pillow case to discover that the two pieces traveled about the same distance, force may have been an influence here. We then examined the bath mat, Selena described it as real rough and that it almost felt like the carpet on the floor. This one was funny, the smooth wooden piece didn’t slide very far, while the rough plastic lid caught and flipped. Of course this caused the lid to go further, so Selena thought she had me on this one so I guess you know this led into another discussion of how the more friction and motion can create hazardous conditions just like a surface being too slick.

Selena is holding the piece on end to show that it flipped.

I loved Selena’s next question, “Why when you stopped the car on the freeway did my books go flying?” You better believe I jumped all over this and we talked about inertia. I explained that while yes, the books were resting in the seat, just like Selena was in her car seat, all objects in the car were indeed moving with the car at the same rate of speed. When I stopped the car suddenly the objects continued to move and Selena felt the force of the straps on her car seat holding her in, stopping her from flying out of her seat like the books did. This time we placed the wood piece on the lid. We first slid it across the table.

Selena came to the conclusion that it is a good thing we wear seat belts and her restraints in her car seat. As I explained to her that the harder I had to put the breaks on in the car, when we got cut off by someone cutting in front of us from a dead stop while we were traveling 60 mph the further things in the car continued to move forward. Selena answered one very important question I had for her, “What would have happened to you if you wouldn’t have been in your car seat?” She answered, “I would have gone flying just like my books.”

I am linking this up at Adventures of Mommydum’s Sunday Science.