Forces and Motion

The first week of April was spring break for the students. It's now the second week of April and they have started learning about forces and motion. On Tuesday, the covered Newton's First Law; the students seemed to get it. Today there was a graphing worksheet involving the tortoise and the hare. A number of students had trouble constructing the graph; they were given a table with distances and times for both the tortoise and the hare and had to construct a two-line distance vs. time graph and answer some questions about speed and velocity.

I'll be looking at the UM Physics Demonstration website this weekend to for an activity for next week.

Electricity activity

It's the end of March and the physical science classes are moving on to their next unit. Today we did a fruit battery activity. The students measure the voltage produced by a lemon and a tangelo (a type of orange) and calculate the amount of current nessary to power a 60 watt lightbulb.

I hoped to use the fruit battery to light one small holiday light (from a string of 50 such lights); however, they didn't generate enough electricity. I used a AAA battery from my calculator instead and had a couple of students light up the holiday light for class.

UM Physics Demonstrations also has experiments on the site and their is a circuit experiment that looks interesting. In this experiment a flashlight bulb is lit up using strip of aluminum, a battery and a flashlight bulb and a "flashlight" circuit (a light bulb, a battery, and a switch) is built on a battery board.

Math, Science Disconnect

The first thing that the students have in physics is wave properties. Today I gave a presentation on light waves focusing on color, microwaves and cell phones; the purpose of the presentation was to identify connections between the classroom and daily life. In the next wave unit I think they'll cover light waves and the electromagnetic spectrum in more detail. It surprising how much math and science exist in a vacuum for most of the students. When the students have to use math in class they whine and complain about how their science class isn't their math class. They haven't done anything more complicated than arithmetic and basic algebra. This doesn't bode well for forces and motion where geometry is involved; the students might be so busy complaining about the math that they miss the physics. Can you learn physics without using math?

Physics

Second semester is underway and the curriculum has transitioned to physics. They've started by studying the physics of waves (wave properties, different types of waves, and the Doppler effect). It seems that the biggest problem that some of the students are having with the material so far is with retention. In some of the worksheets, a few students initially have trouble answering questions because the don't remember the wave properties. However, when I ask them to describe the waves in question they are then able to answer the questions.

Candy Bag Activity

Today I gave the students a design activity; they had to design and build a candy bag using printer paper and tape. The test weight was candy (8 fun-sized peanut M&Ms for second hour and 8 fun-sized Baby Ruth bars for third hour).

A successful design was defined as follows:

1. Bag is contructed entirely of paper and tape

2. Candy fits completely inside the bag

3. Bag must have handles

4. Bag holds candy from the center island in the back of the classroom to the fronto of the classroom and back

5. Bag remains intact

Groups with a successful design keep their candy. It took the groups in second hour 10 minutes to finish constructing their bags. The groups in third hour needed more time. All the bags were successful; if a group finished early I had them test their bag to determine it needed more work. The students enjoyed the activity.

The point of the activity was to give them a glimpse into what engineers do, in general. Since there have been issues with the students not reading directions, I had the class read through the instructions individually first and then I asked the class questions about what they had to do. This approached seemed to work; so I'll use it again for the next lab/activity.

After winter break

Today was my first day back after winter break. The students are working on acids/bases. I'm thinking of a presentation/activity to demonstrate how chemistry is applied in a chemical engineering application. There are a few more weeks left in this semester. Next semester the will cover physics.

Salt Crystal Lab

In the salt crystal lab, the students are growing crystals from three types of salt: iodized table salt, un-iodized table salt, and Epsom salt. Each group prepared a saturated salt solution, added food color, and then poured each solution into each half of a Petri dish (one half contained a sponge and the other was empty). See pictures from one group from each class.

For this lab, I gave an overview of the procedure while the students were at their desks. I also had them answer three questions before the could get the boiling water that they needed to make the salt solutions. My goal was to get them to listen, read, and pay attention. I think the lab went well, but it's difficult to get everyone to listen to and/or read the instructions before they start the lab. Hopefully everyone will have salt crystals next Monday.