More Egg Drop Videos

Here is the last batch of Egg Drop videos, from our second launch day.

3rd Period:
Isaiah's Team
Harrison's Team
Apolinario's Team
4th Period:
Zahria's Team
Willie's Team
Nick's Team
Jeffrey's Team
Jack's Team

6th Period:
Mia's Team

Investigation 18: Motion of a Fan Car

Here is the handout for Investigation 18.1 and 18.2:

Investigation 18 Worksheet

If you were unable to attend class, please get your data from another group.

On the worksheet, draw a diagram to answer question A on page 180.  Then, answer questions B-E on the back side of the worksheet before turning it in.

Egg Drop Video Links

Here are links to all of the egg drops that we did last week.  I couldn't remember all of the teams, and I might have made some errors.  Sorry about that, but I was on the roof!  If I have a video mislabeled, just check some of the other links and you're bound to find yours.  I also have several that I was unsure of the team.

The videos are very short – they only include the drop from release to landing.  I am posting them in case some of you want to see the actual drop again, or in case you need to use the video for your group presentations.

3rd Period:
Stella's Team
Jackson's Team

Unsure of the team, #1
Unsure of the team, #2
Unsure of the team, #3
Unsure of the team, #4

4th Period:
Elena's Team
Fatima's Team
Ethan's Team
Gracie's Team
Iman's Team
Parker's Team

5th Period:
Christopher's Team
Ezrah's Team
Gracie's Team
Jared's Team
Josh's Team
Kiara's Team
Lenquaiz's Team
Lucy's Team
Mazi's Team
Priscilla's Team

6th Period:
Aliah's Team
Austyn's Team
Jeremiah's Team
Kevin's Team
Kiki's Team
Kristian's Team (v1)
Kristian's Team (v2)
Lena's Team
Maryama's Team
Paul's Team
Shira's Team
Sierra's Team
Unsure of the team, #1
Unsure of the team, #2
Unsure of the team, #3

Energy, Machines, and Motion

I apologize that the blog has been silent for the last few weeks.
My plans to record and post videos for the new unit – Energy, Machines, and Motion – have not worked out as well as hoped.


I have put together a compilation of links and stuff below to help with managing any missing work from the Progress Reports.  Sorry this is going up on Sunday, but the Orca News took priority!


If you need any of the handouts, I have posted links to them below.
Unfortunately, with videos unavailable, your only option is to arrange to come in at lunch to do the investigations.  Depending on the investigation, we may be able to arrange ahead of time for me to have it set up and ready to go, and you will only have to do a part of the investigation to understand the concept.  I can then share with you data from another group so that you can complete the worksheets.

Gas Exchange Worksheet
This is actually from the last unit, related to the heart and lungs.
I have added directions to the top of the worksheet so you can access the simulation at home.
There are questions on the back you need to complete on a piece of paper and turn in for credit!

Investigation 5.1: Elastic Force of a Rubber Band

Investigation 6.1 and 6.2: Friction
Answer Questions 9A-D from page 51 on the back side of the worksheet before turning it in.

Investigation 11.1 and 11.2: The Inclined Plane
Answer Questions A-D from page 105 on the back side of the worksheet before turning it in.

Investigation 12.1: The Pulley
There wasn't originally a handout for this investigation in the interests of saving paper.  I have linked the data table that everyone wrote in their notebooks.
Answer Questions 1A-E from page 115 on the back side of the worksheet before turning it in.

Investigation 13.1 and 13.2: The Lever
Follow the directions on the back of the worksheet to answer questions from the text.

We have had two quizzes so far this quarter:
Quiz 1 was our last quiz related to Human Body Systems, which covered the heart and the lungs.

Quiz 2 was related to MSP prep and the beginning of Energy, Machines, and Motion.  It mostly had to do with graphing data from an investigation and using that evidence to make several predictions.
If you took Quiz 2 and did not score 3s on it, you may make corrections on it based on my feedback and turn it in for full credit no matter what you scored on it.  I know that our rule is usually restricted to scores of 2.5, but unless I noted otherwise in the feedback, fixing your quiz will be sufficient!

Experimental Design Challenge

On the last quiz, I asked a question that was more challenging than usual. I asked everyone to provide a focus question, a prediction, and the samples they would test for an investigation about digestion in the mouth, using a strange food.

It was a confusing question with an even more confusing organizer for your answers. Most people struggled with this part of the quiz.  After talking to Ms. Katherine about it, we decided to redo the question and have everyone retake the question through an activity in class.  I have the worksheet and the activity cards linked below if you would like to practice your skills with experimental design.

Experimental Design Challenge Cards
Experimental Design Worksheet

I turned the activity into a bit of a competition, with prizes going to the table with the most complete answers on the challenge questions.  Each person received a different card.  On the front side was a Practice question.  This question was essentially the same for all the cards.  It presented a scenario, and asked the student to identify the independent variable (or the manipulated variable), the dependent variable (or the responding variable), at least two control variables, and then asked for a brief description of the investigation that might be made in this scenario.

After working independently, students compared their answers with others at their table.  They wrote down the answers their teammates generated, and also took the opportunity to help each other provide correct, complete answers.  The groups then flipped the cards over and reviewed the Challenge questions.  Each table could work together to answer the Challenge questions – one at a time, in whatever order they chose.  The team that was able to provide the most correct, complete information by the end of the period (written on each team member's worksheet) won a prize.

I hope that everyone found the activity helpful!  The front of the worksheet counted toward the quiz question retake, and the back side counted toward the competition.

Food Project: Researching Foods for the School Lunch Program

As a final investigation, I thought it would be instructive (and fun!) to test foods of our own choosing, instead of basing everything on the samples provided to us in the science kit.  So I asked everyone to bring in two food samples:  one food that they like to eat at home, either a favorite food or a family-related dish, and one food that they like to eat that is a "junk food" – candy, snacks, etc.

The first thing we did was use the iPads and the laptops to do research online on each of the samples to record nutrition information about them.  This will help as we do an investigation into how they break down during digestion.

Food Project Nutrition Worksheet

I set up our classroom with stations so that everyone could test their two foods.  We put the foods through most of the stages of digestion:  We "chewed" the food using toothpicks or a mortar and pestle; we added amylase to simulate chemical digestion in the mouth; we added gastric juices to simulate digestion in the stomach; and we placed the samples in a hot water bath set at body temperature for an hour or more to simulate the time spent in the stomach.  We didn't get to add lipase or simulate any digestion past the stomach, but I did add a basic solution to everyone's samples at the end to neutralize the acidity to make them safe to handle and dispose.  We used our indicators for sugar and starch at each step of the process to measure any changes in the food, and noted any visual observations we could make.

Food Project Investigation Worksheet

In addition to performing this three-investigations-in-one activity, I added in a final project step by proposing a scenario:  You are a food scientist who works for Seattle Public Schools.  Your boss (someone who is not a scientist) has given you two food samples and asked you to do research on them to determine whether they are appropriate to serve in the school lunch program.  You use your research to support your claim about each food.  Since your boss doesn't understand the science, you will also need to include a bit of a story about each food, explaining what happens to it during digestion in each step:  in the mouth, in the stomach, and in the small intestine.  There are other requirements for your report, which are detailed on the back side of the investigation worksheet.  But, it is not a long and involved project, and could be completed in about two pages of work.  However, to complete all of the items on the checklist, it might take a bit more than two pages.

In addition to the checklist, we will be looking for you to use at least three vocabulary words in your report.  Again, it would be hard to complete the checklist without using at least three vocab words from the unit!  Since this will be graded as if it were a quiz, we want to stress the importance of using evidence to support your claims.  It was one of the main learning goals for this unit!

Please let us know if you have any questions, and we hope you have some fun with the project!

Gluten, Gluten Intolerance, and Celiac Disease

We're approaching the end of the digestion unit, and the textbook has never gotten deep enough with the content to explain what gluten is, let alone how it could cause me – and others who have difficulties digesting gluten – so many problems.  So I did some research online and compiled it into three short readings on the subject.  We covered this information in table groups, and while we're not going to be covering it on a quiz, I thought it was important to try to bring us back to the original  puzzling phenomenon we were trying to solve.

Readings on Gluten and Celiac Disease

After completing the readings, we created final versions of our digestion posters based on everything we have learned in the unit.  It was very clear that we have learned a lot about digestion in a short period of time!

Investigation 7.2: Surface Area and Absorption

Investigation 7.2 is another activity using a model to represent something we cannot see inside the body.  We used a roll of raffle tickets to create a model for the inside of our small intestine to study the importance of surface area and absorption in the digestive process.

Investigation 7.2 Worksheet

The first thing to make sure you remember is how to calculate surface area.  If you aren't sure, Google the procedure and practice it a little.  You will need to remember how to calculate surface area to perform the investigation.

If you do not have raffle tickets to use as a model, do this instead:  fold a piece of paper in half lengthwise, then one more time lengthwise.  Unfold it, and use scissors to cut the paper into strips on the folds, so you have four paper strips.  Tape the short ends of one of the strips together to make a circle shape.  This isn't accurate, but let's assume that the length of the paper strip is 28 cm, and the width is 5 cm.  (This will make calculations easier.)  What would the surface area of the inside of your circle work out to be?

Now, tape two strips of paper together on their short ends, to make a longer strip of paper.  Fold it in half lengthwise, where you taped it.  Then fold it in half again, then again, however you want to fold it fairly evenly so when you are done, you have 16 sections.  Unfold it, and refold on the fold lines in a zigzag, "accordion" pattern.  Now tape the ends of the strip together, and you should have something that looks like the star pattern you see in the upper diagram, and it should be able to fit inside your original circle.

Now, let's assume for a moment that each section of the folded paper is still 5 cm wide, but the sections are now 3.5 cm long.  If there are 16 of these sections, what would the new surface area work out to be?

The important things to understand about the investigation are how the raffle tickets represent the inner lining of the small intestine, how the folds help to increase surface area, and why the increased surface area of the lining of the small intestine is important to absorption and digestion.  The reading in Lesson 7 on surface area does a good job of bringing it all together!  Let us know if you have any questions!

Investigation 6.1: Diffusion and Active Transport

There were two parts to Investigation 6.1.  The first was a balloon activity.  Anise has a very familiar and unique scent.  It is the spice that licorice is made from.  We had anise in two forms for this activity:  anise seeds and anise extract.  The seeds had a slightly strong odor, but the extract was much stronger.  The extract is an alcohol-based liquid, which contains the essence of the anise seed. It is much like vanilla extract, which is also alcohol-based and has the scent and flavor of the vanilla seeds.

We inflated two balloons.  In the first, we poured about 10 anise seeds.  In the second, we added about five drops of anise extract.  We sealed both balloons.  After a short time, we sniffed the balloons.  The balloon with the anise seeds didn't smell like anything other than the balloon plastic.  But the balloon with the anise extract had a strong scent of anise coming from it.  We wondered:  why can we smell the anise extract through the ballon, but not the anise seeds?  We tried thinking about it from the perspective of the "smell particles", the little molecules bouncing around in the air that enter our noses and tell our brains what kind of smell to decode.  When we light a punk stick or incense in one corner of the classroom, it doesn't take very long at all – just a few seconds – before everyone on the other side of the room can smell the smoke.  Why?  And how does it relate to the balloons?

This was our introduction to diffusion, an important concept related to digestion.  It actually gets to the reason why we have to break down foods in the first place.  To understand diffusion, we have to understand how gas molecules move – and we can go back to our learning in Catastrophic Events, when we learned about land and sea breezes, to revisit how gas molecules behave.  It will help us understand how diffusion works.

Our second investigation in Lesson 6 had to do with a model for cell membranes, or the outside walls of our body's cells.

Investigation 6.1 Worksheet

We used a synthetic membrane that looked like a plastic tube-shaped bag. We tied one end shut tightly with twine, and left the other end open so we could add liquids to it.

We used two membranes and two test tubes.  In the first setup, we added a measured amount of sugar solution to the membrane bag.  We then added distilled water to a test tube and lowered the bag into the test tube so it was sitting on the bottom.  The open top of the bag was draped over the side of the test tube.  We repeated this for a second setup, but instead of sugar solution, we used cornstarch solution.

We let these sit for a time, then used pipettes to remove samples of the water from the test tube (not from the membrane bags).  We tested these for sugar and starch.  We found that there was sugar in the water outside the sugar bag, but nothing in the water outside the starch bag.  This was evidence that the sugar could pass through the membrane bag, but the starch could not.  We referred back to the balloon exercise, comparing our results, and tried to determine a characteristic of the sugar molecules that would give them the ability to pass right through the membrane, while the starch molecules could not.  It helped to think back to what each molecule looked like:  Starch is a complex carbohydrate, made up of simple sugars.  Amylase breaks down this carbohydrate into smaller, simple sugars.


This is covered in more detail in the readings in Lesson 4 and Lesson 6 (available here on the blog!).  The reading in Lesson 6 also covers the concept of active transport, which is how our body absorbs molecules and substances that are too large to pass through the membranes by diffusion (which is also called passive transport).  Please let us know if you have any questions about this – it gets to the reason why our bodies break down nutrients during digestion!

Investigation 5.2: Digestion in the Small Intestine

Investigation 5.2 is not in the textbook: it is an activity that I created to round out our studies on enzymes in the digestive system.  So far, we have looked at how our body handles two of the three major types of foods.  Carbohydrates are broken down into simple sugars by amylase in the mouth.  Proteins are broken down into amino acids by gastric juice in the stomach.  But we haven't talked about the third major food:  fats.

The textbook only mentions how fats are broken down in passing, and I wanted us to spend a little more time investigating what happens.  Our resources are limited, but I was able to come up with a synthetic model for lipase that we used for this investigation.

Investigation 5.2 Worksheet

Before I go any further:  I wanted to quickly mention that in our investigations during this unit, we are only skimming the surface of what is actually happening in the digestive system in our bodies.  I have mentioned this before, but maybe not on the blog... I see our middle school science classroom as sitting on the beach of a large lake – let's call it Lake Science.  We're standing on the shore of the lake, skipping stones across the surface of the water.  As we study the digestive system, we're skipping stones across the top.  We get to investigate some of the basics, but we don't stay in one place long enough to go very deep.  It's important to know that we're only visiting the top of Lake Science!  We are, for example, studying three enzymes in digestion.  But there are many, many more than just the three enzymes, just as there are many other types of sugars, many types of proteins, and so forth.  For our skipping stones, we'll study just these basics.  When you reach high school, you'll learn more of the details as you go deeper into the lake.  College will take you even deeper!

Anyway, back to our investigation!  From the book, we learned that there are many more digestive substances added to the mix when the food is released from the stomach to the first part of the small intestine, called the duodenum.  These digestive juices come from several sources, including the gallbladder, the liver, and the pancreas.  More details can be found in the Lesson 6 reading, but most of it is buried in the fiction story about the two aliens that shrink down into someone's body, and it drives me crazy that we're expected to use this as evidence.  At least there's a good diagram of the organs found here!  One important enzyme added when food reaches the duodenum is lipase.  Our claim is that the enzyme lipase breaks down fat into fatty acids.

We took a small amount of oil and a small amount of water and added them to a plastic sample tube and capped it.  We then gently mixed the contents and examined the results.  We saw, as expected, that the oil and water do not mix.  The oil breaks down into large droplets, but quickly reassemble and separate from the water, rising to the top.  We then added three drops of a synthetic version of an enzyme called lipase, and mixed the tube again.  This time, the oil droplets were smaller, and took longer to separate from the water.  We used this as visual evidence that the lipase breaks down the fat droplets found in food into smaller droplets.  In reality, the lipase breaks apart fats called triglycerides into fatty acids and another substance, which can sometimes be measured using pH as an indicator.  For our purposes, though, this will serve as sufficient evidence to support our claim.

Investigation 5.1: Digestion in the Stomach

After giving it much thought, and discussing it with Ms. Katherine, we have decided that there isn't much of a practical benefit to filming the investigations in this unit.  If you were not able to attend a day on which we conducted an investigation, the thing for you to do is to come in at lunch to discuss the investigation with us.  We may even be able to arrange to conduct the investigation with you.

Unfortunately, for Investigations 3.1, 4.1, and 5.1, we have run out of the chemicals necessary to conduct the investigations – even after getting a second delivery of supplies from the district!  This has everything to do with the final food project that I designed for the unit.  Any missed investigations will have to be discussed during lunch and data used from other students' experiments.

Investigation 5.1 Worksheet

For Investigation 5.1, we gathered evidence of digestion in the stomach.  We were introduced to a new enzyme: pepsin.  This enzyme breaks down proteins into amino acids.  The only problem is, we are made from proteins!  We have to protect ourselves from the pepsin, so there is a very clever way our body creates the enzyme so that it doesn't break down our cells.  It doesn't build the pepsin all the way, so that it is fully functioning.  Instead, specialized cells create pepsinogen, which is released into the stomach.  Other specialized cells release hydrochloric acid into the stomach.  When the two meet, the acid converts the pepsinogen into pepsin, and the enzyme is active!

The combination of pepsin and hydrochloric acid is called gastric juice.  Our claim was that gastric juice breaks down proteins into amino acids.  Pepsin alone (in the form of pepsinogen) will not break down proteins.  Acid alone will not break down proteins.  But when mixed together, the acid activates the pepsin, and the proteins are broken down.

We did not have an indicator for proteins or amino acids in the middle school lab for this investigation, so we had to find another way to obtain valid evidence to support our claim.  We used egg white from a hard boiled egg to represent our protein, since it is a solid protein source.

We measured a small cube of egg white and calculated its volume.  We then tied a string around it and submerged it in water in a test tube.  We created several sample tubes like this.  To one, we added gastric juice.  To another, we added hydrochloric acid.  To a third, we added pepsin.  We left one tube alone with just distilled water.  We then submerged all four tubes into a hot water bath set for 37ºC, which is approximate body temperature, and let the tubes sit for at least one hour.

The next day, we removed the egg whites, re-measured them, and calculated the volumes again.  We looked for any change in volume to use as evidence that the proteins were broken down into amino acids.  We used all four results to generate the reasoning to support the focus question: does gastric juice break down proteins into amino acids?

A Quick Visit to the Salmon Tank

Since I have been filming the salmon every week for the Orca K-8 News, I thought I would share a few photos of the progression of our little friends, from their first week up to their first full month.  They are growing by the day, and it won't be long before our K-5 friends are taking them down to Seward Park to release them into the wild!

Salmon eggs, a day after being added to the tank.

 After hatching, the salmon become alevin, and feed off their yolk sac for

a few weeks until they are large and healthy enough to swim around safely.

The salmon are now fry, and can swim all around.

But they are still weak and very skittish.

The salmon are now approaching the parr stage of their lifecycle.

They are eating a ton of food and are growing at a fast rate.

They are no longer as afraid of people as they were earlier, and appear

very curious about what happens between class periods!

They're even bigger now!  Anthony says they will be ready

to be released into Lake Washington in a week or two.

Followup to Investigation 4.1: Supporting the Claim and Updating Our Posters

After gathering our results, we used a modified Accountable Talk worksheet to help us generate reasoning to use our evidence to support or not support the claim made by the focus question.  Some students felt that we could support the claim, and some felt we could not support the claim.  We used the sentence starters on the back of the worksheet to help us press each other for evidence one way or the other.


Accountable Talk Worksheet for Investigation 4.1

Due to an error on my part, third period had unexpected results.  The indicators showed no sugar in any of their samples!  It was due to the fact that I kept the amylase solution too cold, and it settled to the bottom of the dropper bottles.  For the rest of the classes, I kept the amylase warmed in my hands and shook it before dispensing it each time.

This unexpected result gave us a chance to revisit the idea of how to handle outliers and unexpected results.  Most of the students in third period felt they needed to redo the investigation to have sufficient evidence to support the claim.  I wish we had the time to do it!  Instead, I had to ask them to use photographic evidence of the results from other periods.

The second half of the period was spent updating our digestion posters with post-it notes and new supporting evidence.  I asked that the table groups focus on using a specific method for adding or revising information.  We already have an established system for color-coded post-its, depending on what changes are being made.  But now, I am asking groups to provide more supporting evidence than in the past.


When we provided our full explanations for earthquakes, we said it was okay to just say, "we learned it in the pad investigation", or, "we used a computer simulation."  That was acceptable shorthand, since we had all done those investigations and we understood the actual evidence.  Now, we want to provide our supporting evidence in a way that someone who hasn't studied the unit can understand it and accept it as sufficient and appropriate.  I asked that one post-it note be the added or amended explanation, using the sentence starters on the revision key, and a second post-it note connected to the first that supplies the evidence supporting the claim.  We will revisit this after a couple more investigations, and continue to build our full explanation.

Investigation 4.1: Digestion in the Mouth

Our next investigation centered around amylase, an enzyme found in our saliva that breaks down carbohydrates, like starch, into simple sugars.  As we've discussed in the past, just reading this fact, or having the teacher make the claim, is not enough evidence.  We needed to test this hypothesis and use our own results to support the claim.

Because we're also learning about experimental design, I gave everyone a worksheet to help plan this investigation in advance.  However, the way I set up the sections around independent variables and dependent variables was confusing!  Please ask questions if you are not sure.  You should be able to complete the beginning of the planning worksheet, up to deciding on what factors you will need to keep constant.

Planning Worksheet for Investigation 4.1

Investigation 4.1 Worksheet

Most important was choosing the right focus question.  Sometimes, the best way to do that is to change the claim from a statement to a question.  My claim was:

"The enzyme amylase breaks down starch into simple sugars."

This is the claim we want to try to support with evidence.  Before I continue, it's important for me to mention that we cannot completely prove a claim or hypothesis, we can only support it.  We can always disprove or fail to support a claim or hypothesis, but if we were to say that we had proven a hypothesis, it is the same as saying that it is definitely, always, 100% true.  We can't be sure of that!  In science, a lot of our work is to find evidence to support our claims – claims which are often made to disprove or refute an existing claim.  As we learn more and more about the way our universe works, we must be open to the idea that everything we know could be eventually proven inaccurate, incomplete, or just plain incorrect.  It's an idea we'll come back to again and again!

In the meantime, we need to ask a focus question for our investigation.  If we change my claim into a question, we get:

"Does the enzyme amylase break down starch into simple sugars?"

This seems like a good focus question for our investigation.  For our next investigation, you will be asked to determine this question on your own.

One of the challenges of this lab was determining what samples we should test.  We could just put amylase in a test tube with some cornstarch and see if it breaks it down into sugar.  During the last investigation, we learned how to use Benedict's solution as an indicator for sugar.  We could then test the sample after five minutes and see if sugar was present.  Wouldn't that be enough evidence?

The fact that I've set up the investigation for three samples is probably a clue that it isn't.  What I would like you to do is imagine a conversation you are having with someone who is very doubtful of the claim.  They want you to support the claim with evidence.  So, let me start this conversation for you, and I will be the doubtful person – the Skeptic.  I am going to use Accountable Talk to press you to support your claim with evidence.

              You:  "The enzyme amylase breaks down starch into simple sugars."

              Me:  "Can you share your evidence for your claim?"

              You:  "I put amylase and cornstarch in a test tube, waited for five minutes,

                           then I tested for sugar using Benedict's solution as an indicator.

                           the result showed me that there is now sugar.  So this supports the claim."

              Me:  "I am not sure whether that evidence is valid for your claim, because

                           how can you be sure there wasn't already sugar in the samples you used?"

This is something to consider while you're designing your samples to test.  Is there a way you can answer these questions before they are asked?  Can you provide reasoning that uses three samples to tell the whole story about how the claim is supported?  We will revisit this after the investigation and work together to construct our reasoning.

One thing we did on the following day was view a video from YouTube of an x-ray of a person swallowing foods.  You can find many of these videos by doing a search on YT for "x-ray swallowing" or "fluoroscope swallowing."  The first result is probably the one I showed in class.  Either way, it is important that you check the description of the videos to make sure that you are watching a healthy person swallowing... some of the videos are from patients with problems swallowing food.  You might not be watching the normal function of swallowing if you watch one of these.

In the reading for Lesson 4, there is a good diagram of the swallowing process.  One of the big questions we had coming into today's investigation had to do with how we can eat and breathe through the same tube.  Now we know more about the answer to that question!

Investigation 3.1: Learning How To Test For Sugar and Starch

I am hoping to have a video for this investigation uploaded soon.

The investigation had two goals:

The first was to revisit the important pieces of our investigations.  We will need to practice our skills of identifying our focus question, a prediction, independent and dependent variables, and controls, so that we can design our own investigations down the road.

The second was to gain experience with two indicators: Benedict's solution, which is an indicator for simple sugars, and Lugol solution, which is an indicator for starch.  Once we understand how these indicators work, we can use them to gather evidence to support claims related to other foods, and connect these ideas to our bigger explanation about the digestive system.

The first day, we were only able to get part of the investigation done.  We got close to finishing maybe the first test with Benedict's solution, but that was it.  Most of the period was spent doing preparation of our samples.

You may notice the worksheet for this investigation is in a new format.  I am trying to provide us with an easy way to review the major parts of an investigation, so that as we move forward we can practice building these pieces ourselves.  Please let me know if you have any questions!

Worksheet for Investigation 3.1

After completing the investigation, we looked at the data from every group in every class to compare our group's results with the total results.  What we expected to see is that our results were similar to everyone else's.  But this sometimes doesn't happen.  Sometimes, we get unexpected results.  When this happens, we need to discuss what might have happened to result in a different outcome.  What is important to not here is that this does not mean that your group obtained the "wrong" result or a "bad" outcome!  It's very possible that your group was one of the only ones (or maybe the only one) to get an accurate result!  But we need to try to determine what happened.  First we make an observation.  Was our result similar to the one obtained by a majority of the groups?  If not, how could we possibly explain the reason our results were different?  One common explanation was contamination.  For a sample such as distilled water, for example, we logically expect that it will test negative for starch.  But if it tests positive for starch, that is unexpected, and what are the possible explanations?

Many, many students said that they felt the appropriate action would be to redo the test several times to see if maybe it was a mistake or a contamination, and that multiple trials would help to support this claim.  That is very true – we rarely do experiments only once in science.  As my wife says, "that's why they call it research.  Get it?  RE - search!"

Unfortunately, due to limited class time, we can't repeat a lot of our investigations.  We try to use everyone else's result as a simulation of us repeating the experiment.  It's not perfect, but for classroom purposes, it will have to do.  We will revisit this idea of how to handle outliers and unexpected results after Investigation 4.1.

Vocabulary for Lessons 1-3

Here is a PDF of the vocabulary worksheet for Lessons 1-3.  Most of these definitions can be found in the glossary of the textbook, but you can also look for them online.  But, it would be best to try to find definitions for these that aren't too complicated – if you have trouble with that, please ask me for help.  As always, feel free to come in during lunch to use the resources in the classroom to complete the worksheet!

Vocabulary Lessons 1-3

Indicator is an especially important word for the next lesson (Investigation 3.1), and I have already posted about the importance of peristalsis in digestion.

Some Thoughts About "Humans – The Problem Solving Animals"

We read the very brief passage in Lesson 1, on pages 6-7, called Humans – The Problem Solving Animals.  The PDF is linked on the right hand side of the blog page, and there is a podcast for this reading if you would like to just read along.

The reading compared humans to other animals, and makes an argument that what sets humans aside is that we are very efficient problem solvers.  It also suggests that because we can use tools that it separates us from most other animals (and that we can use tools because we have thumbs).

Well, this was written more than 10 years ago.  Science has made progress since then, and any evidence they had regarding their tool argument has been made invalid by a recent study that shows that crows are capable of problem solving and using a series of complex tools to gain access to food.  I am sure that there are Youtube videos out there of the crow getting his food, because I saw it featured on the Colbert Report the night before we did the reading in class.  I think what we can take from this lesson is that science is in a constant state of change.  Nothing is permanent, and our use of scientific method and investigation, using evidence to support or challenge claims, will keep us always moving forward.

The reading is really trying to express that problem solving by working together in teams is the best way to find success in science.  And we will be following that advice as we move through this unit.  Many of our investigations require teamwork to be successful, not only because we need to be challenging each other with Accountable Talk, but because some of them are complex enough that without everyone pitching in, we will not finish within the 50 minutes we're given.

The last thing I would like to say about the reading is that I always get a little riled up whenever I see the famous photo of Watson and Crick that's on page 6.  It's a very iconic image, and it does support the textbook's claim that teamwork will help you solve the problems you face in science.  The only issue I have with it is, these two famous scientists not only worked together as a team to discover the structure of DNA, but depended on the research of a third scientist who does not appear in their famous photo.  Her name is Dr. Rosalind Franklin.

I will just very briefly climb on my soapbox and say that it is depressing to me that almost every famous scientist is a white male – but there's Marie Curie, of course!  If you asked people to name some famous scientists who are not a white male, the first name usually mentioned is Marie Curie.  The second can sometimes be Rosalind Franklin.  She is an unsung hero who has been getting more exposure in recent times, but she nevertheless had to fight against discrimination at every turn and never received proper credit for her contributions while she was alive.  The caption under the photo in the textbook marvels at the fact that "Dr. Watson was only 25 years old when he and Dr. Crick made their important discovery" – that may be the case, but he was still a white male living in a world run by white males!

I am here, teaching science, because I don't want our future history books to be filled with only white males.  Don't get me wrong: I have nothing against white males going into science!  But we need a lot more diversity in our sciences.  In that spirit, I found a one-page biography on Rosalind Franklin online and shared it with the class.  This is a PDF of the handout.  However, keep in mind that there is much more about Dr. Franklin than can be found on this short biography!  There is a really interesting movie called The Race for the Double Helix, which I believe does a very good job of dramatizing Dr. Franklin's role in DNA research, and there are several books that chronicle her entire life that you may find interesting.

Ms. Katherine, of course, feels as strongly about this as I do!  Just "look up" the next time you're in the classroom.  Hanging on the wall are the pictures of many influential figures in contemporary science: Albert Einstein on one end and Sanjay Gupta on the other.  Can you identify each one, and their contribution to science?

Peristalsis: How Does The Food Move?

One of the questions raised by a student on the reflection part of the last worksheet was, "How does the food move upward through the digestive system?"

It took me a moment to realize what he was asking.  He wanted to know how the food goes up in the large intestine, when it seemed that up to that point, all the food was moving down due to gravity.

I then asked, well, what would happen if we ate dinner, then laid down on the floor?  Wouldn't all our food stop moving down?  And what keeps it from coming back up every time we eat?

I shared the story of Cody, my friend Todd's dog. Cody has an unfortunate problem with his esophagus where his food will not stay down.  It is a condition called megaesophagus.  As a dog, he walks around on all fours, and his esophagus is essentially horizontal.  After he eats, his food just comes back out his mouth!  Poor dog!

He wasn't vomiting – his muscles just didn't keep the food going down.  This is the point where we examined a plastic tube cut to the actual length of our digestive system.  It's very long!  Here are the measurements of the average digestive tract:

• Mouth:  11cm, or 4.3 inches
• Esophagus:  25cm, or 9.8 inches
• Stomach:  22cm, or 8.7 inches
• Small intestine:  690cm, or 271.7 inches!
• Large intestine:  152cm, or 59.8 inches
• Rectum:  14cm, or 5.5 inches

To get a feel for how food is moved through our digestive tract, we greased a tennis ball in corn oil to simulate swallowed food, and pushed it into the plastic bag.  The ball barely fit, so it was hard to move it through.  The corn oil simulated mucus and saliva, which helps to lubricate food when we swallow it.  We pushed the ball through the tube, using our hands to squeeze it through.  This is very close to the actual movement that pushes food through the tract:  there are a series of muscles surrounding the digestive tract, and they contract or squeeze in a wave motion, pushing the food along.  This motion of muscles is called peristalsis.

We could have made this model a little more accurate by adding rubber bands wherever there was a border between organs, which is where most of the sphincter muscles are located, which close off the tract between organs.  This muscle is what helps the stomach send food down to the intestines a little at a time, and it's what keeps everything from falling out at the end of the digestive system!

An Interactive Introduction to the Digestive System

We spent some time on the iBooks learning the basics about the digestive system.  The digestive system is the first body system we will be studying this quarter.  A body system is group of organs that work together to perform a specific function.  For example, your mouth and your stomach are both part of the body system called the digestive system.

The interactive lesson introduces us to the idea of different sections of our body, called organs, that have very specialized roles in digestion.  In the simulation, you can send different foods into the body and see how they are broken down into the nutrients we need.

There is a reading in Lesson 3, pages 20-23, which covers the three major types of food: carbohydrates, proteins, and fat.  There are three other major nutrients that our body needs: vitamins, minerals, and water, but we will not be covering those in depth.  There is a podcast for this reading located on the right hand side of the blog if you would like to read along.

Here is a link to the interactive lesson:

Digestion (Flash required)

I handed out a worksheet to help you take notes while you use the interactive lesson and from a lecture I gave to help us skip the reading, but if you missed these, I would recommend that you read the passage on nutrients I mention above (link to the textbook PDF is on the right-hand side of the blog page!), and take notes about the three major types of food.

Then I would take notes on the different things that happen to food as they go through the digestive system.

• Where do they take place?
• What is working to change the food at every step of the way?
• How does our body eventually get what it needs from the food?

We will explore these concepts in much more detail as we move through the unit, but this was a good primer for our upcoming investigations.

Starting Human Body Systems With Digestion!

I'm excited to start the second half of our year together!  We're shifting gears and exploring a new topic:
Human Body Systems.  Our first segment will be on the digestive system.  It should be very informative!

My big focus this unit will be on helping you design your own investigations.  This means we will be revisiting and practicing the assembly of the necessary parts of a good scientific investigation.  But don't worry: we will be helping you along and I am confident that by the end of the unit, you will be very comfortable in creating your own investigations with your table group!

For the first day of class, we discussed a puzzling phenomenon:  Me!  I have had a malfunctioning digestive system for most of my life.  I have, for many years, suffered from bloating, nausea, cramping, and diarrhea.  It was such a problem that I planned most of my life around being close to a bathroom at all times!  Since we don't normally talk about our insides during everyday conversation, I just assumed that everyone had the same troubles that I did.

To make a long story short, by random chance I discovered that I have been sick most of my life because of something related to eating wheat.  If I avoid all wheat (or gluten) products, my digestive system works properly.  I have lost weight, I sleep better, and I feel a whole lot healthier!

So, why is wheat such a problem for me?  I went to see a doctor, but he didn't give me a solid answer.  His first tests didn't give us any evidence, so he asked me to come back for more tests.  The problem is, I have been so busy with school that I haven't gone back – and that was three years ago!  Perhaps now that we're working together to try to explain my wheat problem, I will return to the doctor.  Maybe we can get an answer from my tests by the end of the unit, and we can see how accurate our claims are.

On our second day, our table groups began to assemble an initial drawing of my digestive system.  We used a piece of pizza as our food to follow, since it has not only wheat but a little of everything:  meat (pepperoni), dairy (cheese), vegetables (tomato sauce)... if we can explain what happens to each type of food throughout the process, maybe we can come up with an explanation for what is wrong with me.  Or, we can at least say where the problem is most likely happening.

We will modify our posters as we move through the unit and gather evidence, but we won't change the original work, we'll just add to it with post-its and taped-on paper.  We want to keep track of how our thinking has changed over the course of the unit!