Day 53- Power

We weren’t sure given our limited time if we should spend a day on power, but we decided to, in hopes of making electrical power make a little more sense.

We went to the stairs to take some measurements in order to calculate the power needed to go up one flight of stairs.  They did pretty well with this and it was fairly easy.

We came back and they calculated the energy they gained from the bottom to the top of the stairs, and then divided by the time it took to find the power.

A few practice problems and we were done!  This was smooth and went well.  Jury is out as to whether this was a good use of a day…

Oops forgot to take pics after they calculated power…

 

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Days 49-52 – Using Energy Template

I was out for 4 days for knee surgery, during which the kids practiced doing big conservation of energy problems from the packet (as linked last time), and the Situational Conservation of Energy Stations.  I LOVE these, because they not only have to use all of the skills they learned, but they have to make a lot of judgements about which positions to choose, which measurements to take, and what assumptions to make.  We started a teacher’s document with hints, since we are presenting this at NSTA, but it’s not quite finished!

Overall, they did pretty well while I was gone…  hoping next year to shave a day off of this!

kids’ packet here

teacher’s guide, not quite finished is here

Day 48 – Quiz and Practice

Today we gave the quiz relating to the lab.  Next year, we need to change packet practice 1 to be some quiz review to help them solidify what they learned in the lab, before the quiz.  That should help a bit, this is a LOT of information for their little brains!

After the quiz, we started a bit of Practice 4, which is using the BIG template.  This was my last day in before being out for a few classes for knee surgery, so I was trying to get them to a good place for my subs (my kind colleagues who gave up their prep periods to teach my kids!).

Packet part 2 with template

They did well, and they also did some more proportional reasoning (practice 3) for HW.

Forgot pictures.  😦

 

Day 47 – Using equations and MATH!

Today we practiced using the equations one at a time…  we introduced a 5-step process to solve, including isolating the variable.  This went pretty well, but we do have quite a few kids who are not really proficient with square roots and squares…  I can see that we need to work on some basic math and algebra skills, but I already knew that.  Hopefully after cranking out a bunch of calculations in this unit, these skills will improve!

We of course added proportional reasoning, which I am in love with.  This is also going to be one of our presentations at NSTA.  I seem to find that the kids do better with this than actually solving…  they were very surprised when doubling the velocity quadrupled the Ek!  We forgot to put the place to write the sentence…  have to add that in for next year.  Overall this is going really well so far.  We will start the big template on Friday!

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Day 46- Finishing Energy Lab

Today we did parts 3 and 4, which was waaaay easier than part 2.  Having all groups doing the same part of the lab at the same time, as discussing each as we went was SO MUCH BETTER than how we did it last year.

First I explained to them how they would raise a mass up, draw a force diagram, and then make F vs d graphs.  They were to change the mass for #2, and then change the distance for #3.  This went really well and I am so proud of how seriously they take this stuff!  So cute.  They worked really hard and created their whiteboards which looked great.  By now they are getting the idea of the area being the energy, and how to visually see which situation stored the most energy.  We developed Eg= mgh then moved on!

For the Ek piece, I just did sort of a demo and thought experiment, and we just made up some numbers…  too long and involved the get through logger pro.  I was pleased that they almost all drew the “after” frictionless force diagram correctly, without any phantom force to the right.  Well done there!

We made the F vs d graphs and the last two are the same energy (and area) so we were able to talk about how you can give the same energy through a little force/big distance and a big force/little distance.

Overall really pleased with how this went even though it took awhile…  valuable I think.  On to using the equations and more proportional reasoning next class!

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Day 45 – Developing Energy Equations Part 2

Part 1 went pretty well…  it was definitely way better to have everyone on the same page.  So we continued the same idea today, as we worked on finding the equation for elastic potential energy, through Hooke’s Law.  I really wanted to finish this is one class….

We started out and I briefed them on the procedure and we talked about unit conversions a bit.  Then they set off to work!  They took data easily, and then used Desmos to graph F vs. x.  We had them make whiteboards outlining all of their info…  they are still struggling a bit with not using y and x as the variables.  Still also having trouble with the difference between the variable and the unit.  However, after a bit of struggle they worked it out, and I was pleased to hear quite a few kids trying to figure out the units for the slope, and saying things like “I know the slope tells us the relationship between the variables”.  Progress!

They spent some time working on the equation and what the slope and y-intercept mean.  Then they calculated the area, with units, and I was happy that many recognized this as energy!

We wrapped it up as a class, developed the Ee equation, and then they set off to write the CERs!  Very well d one today.  Having everyone on the same page is going MUCH more smoothly than last year!


Day 44 – Developing Energy Equations Part 1

Today we first did the “flavors of energy” discussion a la @kellyoshea.

Common Types of Energy (ETM Cheat Sheet)

So last year we went for it and had the kids develop all of the energy equations in the lab…  my first year teaching freshman I wasn’t sure they could do it, so I just gave them, and it about killed me.  Last year they did it, but it was hard… we had 3 different stations going, it was pretty confusing, and exhausting.  In the end, they got good results, but we all about died making it happen.

This year we decided to streamline a bit and guide a bit more.  We did the Work station (part 1) as a demo and did it together.  We had 3 different pulleys and raised all masses to the same height, and after the previous discussion, they could see each one had the same Eg since they had the same mass and were raised to the same height.

We “measured” the force you had to pull with, as well as the distance through which you pulled.  Of course, these all should be equal, since they gained the same amount of energy, the same amount work must have been done on them.  These are incredibly hard measurements to get well, so after we tried, we discussed the very rough measuring methods, and I told them I was going to adjust the numbers a bit so they would see the right relationship and not get bogged down in small details….  not the greatest plan, but necessary I think.

Then each group made their own whiteboards and then we discussed…  then they started working on their CERs.  Well done.  This went much more smoothly than last year.  The next two parts they will do on their own!

Lab  here:  Energy Equations Lab

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