As the pendulum swings...

The question I chose to focus on was: Which pendulum will come to rest more quickly- a lighter pendulum or a heavier pendulum?

The materials I chose to use were the three different washers and the string that was provided for us. First I massed the washers using my kitchen scale, although it fluctuated some the masses were about 1g, 8g and 20g each. I then made a pendulum using the 1g washer. I tied the pendulum to a wooden skewer which I taped down to the wine rack so the pendulum could freely swing.

Pendulum set-up

At first I was trying to hold it, but thought that my own movement may have caused the pendulum to move. Since I did not have a protractor to measure the angle, I let it go from a 90 degree angle since this would be the easiest to estimate each time. I timed how long it took to come to complete stop. I repeated this twice for a total of three trials and averaged the times together. I then repeated this with the other two washers being very careful to make the pendulum the same length and dropping from the same place. The average time it took the pendulum to stop, in seconds, for the washers were 1g- 188s, 8g- 291s and 20g- 537s.  I then used the virtual lab to test this out as well. In the virtual lab I set up two pendulums simultaneously with the same length, but various masses and let them go at the same time and each time the lighter one came to a stop first when friction was added. My initial thoughts were that the heavier washer would come to a stop first, but I now understand after the application that the heavier washer has more momentum, therefore taking longer to stop.

The main problem I had was just trying to figure out how to set up the pendulum. It took a little bit of creativity of looking around my house to figure out where it could be placed. I wish I had had a protractor so I could have measured the angle so I would not have to wait as long for the pendulum to stop. In the classroom I would probably have the students explore the different things that affect the period of a pendulum- the length, the mass, and the angle of release. I would stress to the students about only changing one variable at a time. I would have the students offer suggestions for other things that could be used as the bob of the pendulum. I would have my students explore what pendulums have been used for-ie grandfather clocks. I would want my students to learn about momentum and how it can be applied to this situation. This gives them a more hands on approach. I would have them suggest other ways we could experiment with momentum and real world applications. I believe I achieved my goal of understanding momentum better. Overall going through the guided inquiry process helped me to gain a better understanding of not only how inquiry works and how our students my go about the process, but it also I gained a new perspective on the concept itself. Overall the inquiry process is something that should be used in the classroom to help our students become better scientists.

Pendulum in motion

How to get kids excited about science

In teaching we use books a lot to teach our students. Sometimes we use a textbook and sometimes we use trade books. This week in class we read a lesson that used trade books to teach about roller coasters and then have the students design a roller coaster using items available at a local hardware store. While I was working in the library this week a book caught my eye it was called "Mr. Docker is off his Rocker" by Dan Gutman.

He has written a series of books called My Weird School Series where he writes about the various adults in the school. In this book a retired scientist comes to teach science at the school and he makes a clock run using potatoes, puts sodium in water, and makes a pendulum to name a few experiements. The main character A.J. does not like school, and thinks science is for nerds and doesn't think he needs to learn it since he wants to be a football player when he grows up. By the end of the book he is excited and wants to learn more about science and has a lot of why questions...maybe too many questions. It is really a cute little book and something you could read to your students to get them excited about science. The suggested reading level on the inside of the book is 2nd to 5th grade. Just wanted to share this with my fellow teachers.