Exploring the Electromagnetic Spectrum

One of the topics I have to cover with my students is the electromagnetic spectrum. It’s not easy getting them interested in it based on what it in their textbooks, and no wonder. The information is wordy, larded with unfamiliar terms that have little day to day use, and the two dimensional static pictures do very little to convey the information in a way that makes sense to visually oriented learners.

One of the sites I’ve heard mentioned quite a number of times since I’ve been at Walden has been BrainPop, so I finally took a good look at it. They have a wonderful set of videos and activities on all aspects of electricity and magnetism, including of course the electromagnetic spectrum. I know my students would get involved in the activities found there, and would even take the little quizzes, which I could use as informal assessments, opportunities to see where I need to reinforce teaching; or even as extra credit.

The challenge with using the program is two-fold: first and foremost is the cost. Our school does have one laptop cart which I can use on a rotating basis, but it is extremely unlikely that our budget would be able to pay the cost for the “laptop cart” license. It’s hard for me to get funding for anything for science that is not in the district mandated curriculum, since science is not counted toward our school’s “AYP” score. Any money not already spoken for goes to support extras for reading and math, which are the big two in our state’s high stakes testing. (There are ways to try to get it funded by applying for grants; I will have to see if I can have any success that way.)

The second problem has to do with the state of our laptops. They are already extremely shopworn, and we just don’t have enough to go around for an entire class. Also, there are four classes vying for their use at all times. So this presents an ongoing challenge for use of technology in our classrooms. It’s really a shame, since our students come from low SES homes, and need high tech education even more than their more fortunate peers, who are likely to have access to good technological resources outside of school and to have technologically savvy parents. One of the intentions of public schooling is to level the playing field for all students, but we still aren’t there yet, despite good intentions and some progress.

There are free sites that I can use also, NASA has some good material, unfortunately much of it is written well above the reading levels of my middle years students, and they don’t have the “catchy” animations of BrainPop, but they are free and have no advertising. The BBC has some interactive game-type programs that allow students to manipulate mirrors and reflections. This is aimed at slightly younger students, but I believe middle school students will enjoy playing with it as well. They also have a “mystery” program where you need to use knowledge about light to help the hero find her way out of the hall of mirrors. I have noticed in the past that the BBC is linked in closely with the UK national curriculum, which is very helpful even for me as an American teacher.

I want to try to get my students to think about using computers as work tools as much as possible, not just as glorified entertainment devices. It is critical that they make this connection so that they will not be left behind their age mates when the time comes to compete for jobs.

List of websites of interest to this topic:

http://www.brainpop.com/science/energy/electromagneticspectrum/

http://www.bbc.co.uk/schools/ks2bitesize/science/physical_processes/light/play.shtml

http://www.bbc.co.uk/schools/scienceclips/ages/10_11/see_things.shtml

http://imagine.gsfc.nasa.gov/docs/teachers/lessons/roygbiv/roygbiv.html

http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html

http://spaceplace.nasa.gov/cosmic-colors/redirected/#/review/cosmic-colors/preloader.swf?path=/review/cosmic-colors/cosmic_colors

A note: I apologize to my classmates for being late with this, my district moved our deadline for report cards ahead by one week and unfortunately my blog got caught in the landslide. I hope this didn't inconvenience anyone too much!--Eileen

Getting myself in hot water!

This week’s experiment was one I had never performed with a class before, so my conclusions were less foregone than other experiments I’ve done for this course. I did have a lot of background knowledge about insulation, just from everyday use and research I have done as a homeowner. I selected newspaper, aluminum foil, a china saucer and a down vest to act as insulators in my experiment. I used the first two because they are materials I have commonly seen people use to wrap things they want to keep hot. The saucer idea came because I’ve seen people put their saucers on top of their cups to keep their drinks hot when they had to leave them for a bit. Finally, I used the down vest because I know down is a good insulator for geese and humans, so I figured it would work well for hot water too. Both the newspaper and aluminum foil were folded into 8 layers. My hypothesis was that the down vest would keep the water the hottest after 30 minutes.

My results showed that after 30 minutes, my water which was initially 155º F (using my digital probe thermometer, which has a built in timer) were as follows:
Newspaper:    116º F
China saucer:  117º F
Aluminum foil: 118º F
Down vest:      121º F
So my hypothesis was supported. The range of difference in the other three tested materials was quite small, but I have confidence in the accuracy of the temperature measurement due to the use of the digital probe.

If I were to do this experiment again, it would be interesting to use some materials commonly used as household insulation. I would like to try a “lid” made of Styrofoam, some insulating expandable foam sprayed onto a cardboard circle cut to fit the top of the mugs, and some Fiberglass insulation, provided I could find a way to contain it so that I could avoid glass slivers. With these, I could do a direct comparison of the R value of each material before using it. I believe that the Fiberglass would do the best job of insulating, for the same reason that down was the best insulator: it traps air in small spaces.
The insulating expandable foam might also do quite well, I have less experience with it but it would be an interesting product to test. It could certainly be useful for “tightening” air leaks in the home, so if it performed well as an insulator in this experiment, it would be well worth considering for household use.

To address the question of whether hot dogs or spaghetti would stay hot longer or cool faster than the hot water, I believe that they would cool faster. I was having a discussion today with my seventh grade class about the effect of large bodies of water on weather, and we noted that meteorologists have observed that it takes water a long time to warm up, but it is much slower to cool off than land is. (This explains why coastal areas tend to have milder winters in general than inland regions.) I think that the same would apply to water and other solids, including hot dogs.

These experiments would not be easy to perform in my classroom due to lack of access to hot water and some reluctance to use hot plates to heat water (or hot dogs). I do believe with modifications, such as exchanging the mugs for paper carry out cups and adjusting the length of time for measurement, students would find this activity engaging, and would be able to see immediate applications to their lives.

Science inquiry on momentum 3/11/12

The question I chose to investigate is “Which pendulum will come to rest more quickly—a lighter pendulum or a heavier pendulum?” I chose this since I have investigated pendulums with fifth grade classes in the past, but this was a factor that had not been considered. My hypothesis was that the pendulum with the greater weight would have greater momentum and would continue to swing longer.

My setup originally had an error. I made each string supporting the pendulums the same length, which made the heavier pendulum longer, since I was using a larger, heavier bob. The heavier pendulum was about 4 cm. longer than the lighter one. (See the first picture.) I performed two trials with these pendulums before I realized my error and corrected the lengths of the pendulums so that the total pendulum length was equal. (See the final two pictures.)

My pendulums were suspended from pot hooks in my kitchen (see the second picture), allowing a stable point from which they could swing.

I then put each pendulum through three trials. When I had done the “error” trials, I discovered that I had to make a decision as to when I would decide when the pendulums had come to rest. I determined for the sake of the experiment that this meant that the pendulum must remain entirely still, which took more time than expected. For the lighter pendulum, the average time for the pendulum to come entirely to rest was 303.3 seconds. For the heavier, the average was 615 seconds.

I did expect the heavier pendulum to take longer to come to rest, since it would have the greater momentum since it had the greater mass, but I did not expect the pendulums to take as long as they did to come to total rest.

Overall, the experiment went well, although it was difficult getting the pendulums started and also starting the stopwatch at the same time by myself. This will be less of a problem in the classroom since the students will be working in groups.

In order to get a modified result, one that I hope would result in a shorter time for the pendulums to come to rest; I would have them drop the pendulums from a lower height. I wanted to keep consistent throughout the experiment so stayed with a similar drop height. I also wondered if longer strings, resulting in a longer period of motion would also allow the pendulums to come to rest more quickly. I will have to try that out at home to see what happens.

I may use this experiment in my class when I teach force and motion to my eighth grade in the last quarter. Thinking about ways to make it more exciting include using “Jeopardy” style trivia on the topic, which they love, while they wait for the pendulums to stop (I’ll have to think of a way to be sure someone remains the spotter!). Super long pendulums hung from the ceiling with larger masses done as a large group activity would likely spark their interest too. I would also use the “Pirate Ship” animation displayed on my class smart board as a “bell ringer” activity.  This activity can be related to familiar things such as playground swings and amusement park rides, so they can understand the principle has applications in everyday life.

This experiment helped me to understand more about momentum, and to be able to see it separated from surface friction. I want my students to understand about the air exerting friction on objects, and I can follow up with information about rocket ships and re-entry; and why heat shields are necessary.

I want to be a scientist!

Enjoy....Outreach: xkcd

Some Final Thoughts

I hadn't kept a blog in many years, and the last one was just for personal purposes. I had fallen out of the habit. But I have enjoyed writing this one, and haven't minded making the posts. I have used this as a place to be a bit more "free" in my expression, certainly less formal than my traditional classwork that accompanied the course for which I originally set this up.

I believe I'm going to keep this going. I'll have to see how it goes over time. My district and my school are going through a time of serious upheaval. I've been at this school for nearly eight years now, and I am beginning to wonder if it's time to make a change.

Being a teacher is never an easy job. Being a teacher in an urban district that constantly finds itself under fire is even more difficult, I believe. We encounter disrespect from our students, to a level that would make your hair curl. We have little parental support, and the general public uses us as a scapegoat for all that is wrong in society, heaven knows why.

I entered the Masters in Education program at Walden University knowing that it was going to be extremely difficult to keep up with the demands of home, work, and school especially at this time of my life (I will be turning 53 in April). But I felt that it was important to do something to better myself as a teacher, and I specifically sought a program that matched up with what it is I do, teach middle school science.

It's strange, going to an on-line university. It takes a measure of self discipline that I would never have thought I had in myself. You can't sit in a classroom and discuss, not in any traditional sense, and there have been many times were I've wondered if I was only one in the class who was not understanding what in the world was going on.

But somehow, you begin to develop that sense of community. Many of the names are the same, course after course. I begin to recognize people's styles. And my classmates make a contribution to me, in ways that I don't get to thank them for.

So I will here.

Speaking of names remaining the same. Mine is not going to, for much longer. Just because I've managed somehow to adjust to the workload of Walden, plus teaching 100 feisty teenagers, I decided it was time to add a new challenge to my plate. I'm getting married in June, on the first day of my summer vacation (so it had BETTER not snow this winter!). It's the summer solstice, which somehow is appropriate for a science teacher, I feel.

See you all in the next course, and I'm looking forward to more adventures in science teaching, and in life!

Eileen (soon to be Montgomery!)

A low tech experiment adventure.

Here are some photos taken on Friday of one of my eighth grade classes performing an experiment on physical and chemical changes. They were totally engrossed in the work, which was very gratifying for me as a teacher. I had expected this to take a single one hour class period, but it didn't, I ended up "stealing" this class back for an hour and a half at the end of the day, so total time on task ended up being more like 2 to 2.25 hours. Seems like a lot for a simple experiment, but it has been a while since we've done a hands on inquiry, so they are out of practice, to say the least.

Picture three is of special interest for me, it's an anomaly picture. The students had mixed cornstarch and vinegar in that "cell", which should have produced a clear solution, but as you see, there is a light purple tinge to the solution. I sat with the group as they discussed their results. One of the students noted that their rinse water had become contaminated with iodine (one of the three liquids they were testing against the four powders: baking soda, baking powder, cornstarch, and powdered sugar), and that perhaps the purple was coming from that since the cornstarch with iodine had turned dark purple. 

This was based off an experiment that is part of the district mandated curriculum. We don't get to vary from what's required, but sometimes, by selecting carefully from the options that are there, we can come up with a winner. This was one. The students were all able to articulate the difference between a physical and chemical change, and they understood what "reactivity" meant. Not all of them were able to write about it, but they could all explain verbally.

And  now technology has completely failed me, my internet connection has crashed, so I'm going to copy this post so I don't lose it. Something to be said for the good old fashioned low tech, after all!

A Day Late, and a Dollar Short...

Well, as it turns out, more than a day late! I've spent this week down the rabbit hole, had my observation on Monday (everything went well, hooray!), and then 100 report cards had to be completed by Wednesday night. That meant last minute review of 95 notebooks, which is actually a pretty good number. There are always those few who absolutely refuse to do their assigned work no matter what incentive you dangle before them; neither the carrot nor the stick will do the trick.

So I just figured out late last night that this blog entry was due LAST week, although the write up of the experiment wasn't due until today. My apologies to everyone, I feel as if I'm constantly chasing my own tail, and heaven knows what I would do with it if I ever caught it!

On to the experiment. I knew in advance what the results would be, no spillover, of course. The less dense ice floating in the denser water, displacing the volume to which it would melt (or close to the same volume... as water expands when it freezes, which helps to account for the weathering of rocks).

The interesting part was in the research. The opinions are SO heated... it seems funny when the image of the scientist is that of someone who is coldly logical, working off facts alone. There was a great deal of hedging in the language around the causes of global warming (or to be more politically correct, "climate change"). Yes, it is still in the hypothesis state right now, but all evidence suggests that the average temperature is indeed climbing at a rate not before seen in recorded history. The factor most likely to be implicated is the industrialization of the Earth, i.e., the burning of fossil fuels and other things that lead to the release of greenhouse gasses.

A great deal more research needs to be done, of course, but in the meantime, it is my opinion that it would be prudent do find ways to decrease human spurred release of carbon dioxide into the atmosphere, or ways to counter such release... which would require a massive effort to "reforest" rather than "deforest", which is the direction we are currently headed in.

As to the experiment itself, it would be a good way to help students understand that the melting of the "North Pole" will not flood the Earth, but I believe that clouds the larger issue. I suggest that this experiment be paired with one showing what will happen when land based ice sheets melt, for example the ones covering Greenland and Antarctica. (The model could be created by placing modeling clay "land masses" into the bowls, placing the "glaciers" on top of the land masses, then filling the bowls to the brim with water.)

I think this would give students a much better picture of what can and will happen when the land based ice sheets melt. There should be some spectacular "floods" for them to witness.

Further, I think that they would need to follow up with some research about what happens to the animal and plant life of the Arctic region when the ice melts, perhaps even put tiny polar bear models on the original ice floes so the students can see that the bears will have no where to go once the ice melts. That should generate some thought provoking discussions.

All in all, a decent example of the inquiry method of science teaching. With supports, this could well illustrate the issue of climate change for my students, who live very far from nature.