Ms. Hohenemser

Over the next month, our class will be investigating Lemna (duckweed) and Azolla (an aquatic fern) to see which one will produce more biomass. Scientists are investigating these two plants as possible food sources for livestock and humans and/or as a non polluting biofuel. We are wondering which will produce more biomass over a month of growing in our classroom. We have set up pond like environments and are asking questions about biomass and also which plant is more likely to become invasive. Some students are investigating whether the plant grows better in plain water or a pond environment. Stay Tuned…

Photo creds to Casey for middle photo taken through the microscope with his iPad

This video was actually taken last year when the oxygen probes were working. So we will use it as our data source for this year. If you were absent this day, please see me to get the accurate numbers for the CO2 monitor, but you should be able to get the Oxygen data from the video.

June 12, 2018:

Today in class I am asking you to write a letter to your 18 year old self at the end of your senior year in high school. You don’t need to use all the prompts below, but try to write about as many of them as you can during this class period. Since I won’t know how to contact you as a senior.. I am asking you to name it “letter to my senior self” and save it to your google docs. Here are some ideas to get you started writing.

What is most important to you now?

How are you feeling about the end of middle school and the start of high school

Who are your best friends? Who do you think you will still be friends with in 4 years?

How do you spend your time on electronic devices (phone, iPad, computer) social media (twitter/snapchat/instagram etc), apps, games, 

How much time do you spend on your device a day? Do you predict this will change during high school? in which direction

What non-screen activity do you like to do in your free time?

What’s your favorite extra-curricular activity now ? (sports/dance/art/music/drama/other) What types of clubs do you think you will have joined by the time you are a senior?

Who is a person you really admire now ?(sports/actor/politician/author etc)

Do you think you will be in a leadership role in one of your high school activities? Which activity?

Do you have a favorite subject in school…now?.. how do you predict that it might change over the next four years?

What career do you think you are most interested in now?

What college (s) do you think you will apply to? If you don’t think you will go to college, what will you do after graduation from high school?

What type of music do you listen to now? Favorite bands/singers etc.

What is your relationship like with your family members now (parents/guardians and siblings)? How do you think these relationships will change over the next four years?

How tall are you now? How much do you weigh…DO you hope to grow or stay the same size?

If you could travel anywhere in the world where would you like to go?

Who do you think will be president when you are a senior?

What personal goals do you have by the time you graduate from high school? (fitness/social/academic/leadership etc)

What advice do you have for your 18 year-old self?

Who will you rely on to help you make good choices during high school? Who might encourage you to make not so good choices?

There are links to facts sheets in the post below this one. Check those out on Tuesday, May 15

The 21st annual Solar Car Challenge is happening at Cal Young Middle School on June 9th from 9:30-1:30 ish. Our science classes will be sending the two fastest cars from each class to compete in this annual race. 

Beginning Wednesday, May 16

1. Each student will work on the bottom view of your car design. Each person in the group must complete an actual size drawing on the large graph paper. Make sure you read the tips provided in the post below about chassis, axles, bearings and wheels.
2. Bring the drawings to the front counter and get them approved and initialed by Ms Hohenemser. You will keep these until all drawings are completed and then will self score and turn them in 
3. Trace the outline of your chassis (body shape) using the overhead projectors on the front counter near the door onto a blank piece of legal sized white paper. Cut out the shape with scissors and put all scraps in the recycling
4. Fill out your Materials Request Form (green) with your names and select the parts you will need to make a rolling chassis; this includes thin or thick balsa wood or foam core for the chassis, axels (aluminum or steel), wheels (large or small) and driven gears, the one that goes on your axle (12, 20, 30 or 40).
5. Bring the filled out Materials Request form to Ms. Hohenemser and receive your parts. You will need to bring this form any time you want to trade out parts or get new ones
6. Attach the traced drawing to the wood/foam with tape and trace around it onto the wood/foam core BEFORE you CUT the wood, ….Use the triangle to make parallel lines on your wood to show EXACTLY where the axels will be attached. Make some extra parallel lines so that you can line other items up. 
7. Check out a knife at the front counter and get a cutting board from the bottom shelf of Ms. Hohenemser’s computer cart  and cut out your balsa wood/foam core. Always cut towards yourself against a straight edge for safety and be sure to use a sharp knife that has a triangular point (Ms Hohenemser will do a demonstration in class)
8. While one student is cutting the chassis, the other partners should prepare the other parts needed for the roll down test. If you are using brass bushings, follow teacher directions on how to cut them. Cut your axels to the right length (using the huge bolt cutter behind the front counter) and file the sharp ends by following the directions in this video.
9. Use the metal triangle and hot glue to attach your bushings to the chassis. It is super important that they are on straight and parallel to one another. (Check out this video at 2:48 to see how to attach the bushings and axels.) Attach the gear and wheels to the axles.
10. You are ready for the Roll Down test. Get the Yellow Roll Down sheet from the front counter file folder and make your measurements including finding the mass of your car. Record your Roll Down score on the bulletin board data table as well as the class spreadsheet on your teacher’s computer. A score of 20 or higher is generally good. You may need to make some adjustments to reduce friction or re-glue your bushings if the car does not role straight. You can use powdered graphite to reduce friction in the bushing. 

After you are satisfied with your Roll Down Score, it’s time to get it is time to get your motor, wiring, mount and battery pack attached. . Make sure you have recorded your scores on the spreadsheet on your teacher’s computer, 

12. But first you must complete the top view of your design. Decide where the motor will go, finalize which gears you will use and draw in your solar panel mounts and battery pack. Get your drawing approved by your teacher before going to step 13.

13. Bring your Green materials sheet to the front counter with the items listed above filled out. You can choose from a prewired motor or do your own wiring. You will attach your motor with hot glue and your battery pack with velcro (please do not glue it). If you plan to use a motor mount you can also ask for some tiny screws to attach the motor to the mount or just glue it directly to the chassis. Be careful not to get glue in the teeth of your gears.

14. The important thing about mounting your motor is to get the gear spacing perfect. Gears that are too tight will reduce the rotational force that comes from your motor and slow down your car, but gears that barely touch each other will also not move your car very fast. You have to find that perfect sweet spot where they make good contact but don’t exert too great a force on each other.

15. Once you have mounted your motor with a pinion/driver gear, attached your battery pack with velcro and inserted your used batteries, it is time to take your car “out for a spin”. ALWAYS MAKE SURE THERE IS SOMEONE AT THE OTHER END OF THE TRACK THAT YOU TRUST. YOU DO NOT WANT TO HAVE TO START OVER! Get a green speed sheet for your group from the file folder on the front counter. Your initial speed test will be completed on the track in the back off the classroom on the roofing paper. This track is marked at 8 meters in length. In order to calculate your speed you will divide 8m by your car’s time in seconds.Use your iPad or phone for timing. For example 8 meters in 4 seconds would be 8/4= 2 m/s. A fast speed on this track is about 3 m/s. Record your speed on the bulletin board chart as well as on the computer spreadsheet.

16. Once you are happy with your time trials on the 8 meter track, you are ready to set up the hallway track and get a 20 meter speed (this should be faster than your 8 meter speed because your car will likely not reach a terminal velocity on the 8 meter track). You may need to add some traction to your drive wheels (the ones that are connected to the motor) You can use rubber bands or part of an inner tube from a bike tire. You may also decide that you want to make some kind of bumper for your car if it always pulls to one side. Possible materials are aluminum axel material or zip ties or anything else you can think of.

17. Once you are happy with your hallway speed without a solar panel, record your top speed on the bulletin board data table and the computer spread sheet as well as on your green speed sheet. It is now time to attach your solar panel. A good time for the 20 meter track without a solar panel is 5- 6 seconds.  So the speed would be 20 m/ 6 sec = 3.3 m/s  20m/5 seconds= 4 m/s.

18. Now it is time to attach your solar panel mounts. Use the scraps that you made cutting out your chassis or any of the balsa scraps from the scrap box near the table by the whiteboard. The solar panel mounts should be glued down, but your solar panel MUST BE ATTACHED WITH VELCRO. Your teacher may give you a broken solar panel to test unless there is an outdoor track set up. This is to avoid breaking working solar panels in crashes.

19. For you last required speed test, you must run your car in the hall with batteries and the solar panel. Record your speed in m/s on the bulletin board data table and computer spreadsheet. This speed will be slower than without the panel. Finish your green speed sheet and turn it into the basket. If we have time, we will set up an outdoor track.

Before you start, please turn in your SN to the tub. Also if you didn’t turn in your yellow packet (completed) yesterday, turn that in now as well.

Assignment for Friday May 11th 

Simple Machines:

We are transitioning from PS3 How will it Move to Electric and Solar cars starting Monday. A topic that is not covered in our physics unit is simple machines. There are six types of simple machines. You will research the main three: Inclined Planes, Levers and Pulleys using the resources below. You will make a mind map/concept map on a large sheet of paper illustrating what you learn. The words Simple Machines should be in the center of your mind map/concept map. Your final product should have images with some examples of each simple machine, as well as key information as to how it works and what makes it a simple machine, how does it make work easier?  If you have extra time, you can research the other three types of simple machines (screw, wheel and axel, wedge) and add them to your mind map. Make it colorful and artistic with images and words describing your findings.

By the end of the research and mind map creation, you should be able to write a few sentence summary of what makes something a simple machine. Add this sentence to the bottom of you mind map. Don’t forget your name and period before you fold it in half and turn it into the basket. 

Website on Simple Machines

 Pulley Video

Incline Plane Video

Lever Video

Wheel and Axel video 

The Wedge video

If you have extra time check out these Rube Goldberg devices using simple machines. Rube Goldberg was a cartoonist who designed impossibly complex devices in his cartoons to do ridiculously simple things.

Rube Goldberg with 6 simple machines

Honda Cog Video

photography rube goldberg

If you want more: Here is a Bill Nye on Simple Machines