Food Webs

 How do you make a food web?  Start with a list.  We finished the owl pellet dissection.  The kids made of list of animals in the owl pellets: voles, moles, mice, shrew, and birds.  Next, we research what small rodents eat—usually, crab grass, tubers, and tree bark.  Moles and many birds are omnivorous.  Add insects to the list.  Owls can eat bats.  Add bats to the list.  Now, separate the list into producers, such as plants, primary consumers or herbivores, such as sparrows, and secondary consumers, such as owls, robins, moles, and bats.  Next, organize the groups into trophic levels, roughly like a trophic pyramid or energy pyramid.

In a food web the arrows go from the meal to the diner.  Below of food webs created for the owl pellet lab.

Biology on a Budget: Homeostasis Lab

 Oh!  This is an ideal lab—cheap and instructive!  Keep the Patient Alive! is a homeostasis lab.   If you use Apologia Biology, the term, homeostasis, is in Module 1.  The lab involves keeping 200 mL of water at body temperature, plus or minus four degrees.  (Instead of a hot plate, you could keep a container of ice and an electric kettle available.)  Feel free to do this experiment in a pan on the stove.  

Here is a popular lab called Homer-ostasis, featuring Homer Simpson.  I like the lab idea because the patient is leaking and turning different shades of yellow, as though he were jaundiced; however MANY people object to The Simpsons.

What are we going to do?  My kids will get a stack of yogurt cups, thermometers, water, ice, and an electric kettle.  The goal is to keep the water temperature at 37 degrees Celcius (+ or - 4 degrees) for five minutes—without any other instructions.  Yes, the kids may name the patient and draw cartoons on the cups.  This is a good time to talk about experimental design, too!

Owl Pellet Dissection

 The Co-op Biology class dissected owl pellets today.  I bought large pellets, which have more skulls.  However there weren’t enough skulls from six pellets to make a good data table.  The dichotomous key for barn owls was not as useful as the bone sorting chart.  Too many skulls were crushed to determine gaps, etc.  Live and learn.  So, you’ll need pellets, paper plates, toothpicks or probes.  (I had gloves and masks available, leftover.). Another tip.  You may want to soak the pellet in soapy water to loosen the fur.  We just break apart the pellets.   Take a look.

Science on a Budget: Cannibalize kits!

Generally, kits are not bargains.  Good Will  frequently has listings for lab kits.  These science kits are titled eScience labs, Science Interactive, Labpaq, Hands-on Lab kits, and FOSS Next Generation.  The eScience, Hands-on Labs, and Labpaq kits are usually kits college professors assign to online science students.  Innovating Science, FOSS, Nasco, and Delta Science are usually elementary or middle school kits.  I bought two FOSS kits for science camp from Good Will;  my husband, Rob, is going to use the kits for Physics because the electrical components work well.  

Often the kits were unused and donated to Good Will.  They are available on eBay, though seldom at a good price.  My target price for kits is $25, including shipping.  Look at the kit’s contents.  Does the kit have a thermometer, digital scale, beakers, pH paper, cylinders, etc?  Generic lab equipment, such as beakers and cylinders, is always useful.  (Note to self: you already have a bin full of beakers and cylinders.)  Filter paper and pH test strips last a long time.  Make sure the contents in the kit have a value greater than $25 before you bid.  I’m not too concerned about small, random packets such as colored beads labeled ‘DNA’ or ‘Population Ecology’.  I have two boxes of mini bags to use for random labs.  I cannibalized the kits for beakers or dissection specimens and tossed them into a box.  I can always Google pop beads and DNA lab.  Below are examples to see the contents from sample kits. Happy hunting for science kit deals!

Discrepant Events: Poly Density Bottle

Yesterday, I taught a lesson about CER Claim Evidence Reasoning with a Poly Density bottle.  (The video is below.). Discrepancy events are a popular science ‘hook’.  I use them to teach kids how to report data from a lab.  It helps to have a question.  I asked the kids if the white and blue plastic beads were the same. 

 

So, when is the CER process useful?  My teens write four formal lab reports each year.  One Chemistry lab is Can You Make 2Grams?  The kids dry a white powder, a precipitate.  First they report the data.  The goal is to produce two grams of a white powder.  They don’t.  Instead, one kid may produce 1.0 gram and another teen might produce 4.6 grams.  The teens record the results with the errent error in the report.  Next, in the discussion section, the teen explains what went wrong.   Here is where CER or claim-evidence-reasoning helps.  If a student has 4.6 grams, the white powder is still wet.  It may feel damp or the mass decrease after a few days, evidence the powder is still wet.  Students may reason that the powder had not had sufficient time to dry to produce meaningful results.  Basically, CER is useful to help kids draw conclusions from data or observations.

Biology: Ecology and Module One

 We started Ecology with a giant list of organisms we’ll name and organize into a large food web.  Module 1 in Apologia Biology has a biological key—essentially a dichotomous key.  We need to do several to get the hand of keying or identifying organisms.  Let me share a few.  This key series begins with a pasta dichotomous key—very easy to understand.  Here is a button key.  (Next week, the kids will create their own dichotomous keys with a bag of buttons.)  This website has two popular keys : insects and leaves.  This key is another leaf identification key; it has an excellent chart with tree and leaf characteristics, such a lobed or serrated.  Here is an easy insect key.  (Here is a fairly miserable, 15 page insect key, if your teen likes a challenge.  I always have one teen who thrives on harder assignments.)  Another group of key are fun or wacky: Wacky People Dichotomous key, Monsters Key and Pamishan Creatures.  Some kids understand the process after doing two or three keys; others need more practice. 

 

Biology on a Budget: Jelly Belly Dichotomous Key

 The Apologia Biology textbook uses the term biological keys instead of dichotomous keys.  Dichotomous keys help kids identify species.  For each organism you are determining the name, you start at number 1 with two choices and proceed.  The best way to learn how to read dichotomous keys is to do a bunch.  Start with the Jelly Belly Dichotomous Key Lab.  (Here is a second Jelly Belly key lab.)  We’ve had some problems with the key because the number of Jelly Belly flavors can vary between 20-50 types.  We’re going to test this Jelly Belly lab for comparison.  I want to test 20-50 flavors, too.  (Happily I do not like Jelly Belly jelly beans or I would be sick.). I’ll post results.  The first lab recommends using ten jelly beans.  We use at least 20 per group.  You be the judge.  

Apologia Biology: Day One

 Let’s roll!  Our first day of class was a mix of Module 1 and Module 10, Ecology.  The kids made list of organisms.  Let me share today’s schedule.  BTW the classes run 1 1/2 hours.  

  First we made a class list.

The class list of organisms has mammals, insects, plants, trees, birds, and a few reptiles and amphibians.  Next the kids discussed types of organisms.  I drew a pyramid to introduce Energy Pyramids.

The kids sorted cups for Levels of Organization to see what they already knew.

Next was the Density Bottle, a discrepant event to introduce Claim Evidence Reasoning or CER.

Finally, we started the Biological key in Module 1.

Freebies!

I promote Flinn Scientific all the time.  They have many freebies, such as Egg Geodes with alum.  It can hard to sift labs from 856 downloads. (Many freebies are organized in a better manner here on the Canadian web site.). Let me share some of my favorites.

Physics and Physical Science: 

 Newton’s Laws Activity Stations, Slingshot Cars, Spinning Can, Binder Clip Catapult, and Centripetal Acceleration (with a metal hangar and a penny.)  

Chemistry and Physical Science: 

Boyle’s Law Lab, Reaction in a Bag, Flinn at Home Chemical Labs, Quick Freeze,  Plotting Trends, and Benzoic Acid Blizzard in a Bottle.

Biology and Life Science: 

Lynx Eats the Hare, Transcription Translation Foldable ,   Karyotyping Cancer Cells, and Genetically Engineer Cleaner Clothes.

Science on a Budget: Equipment

 There are odd items on sale Labor Day which might be useful for your classroom.  There are screenshots below.  Consider an electric kettle. (Home Depot has the same price.) I use mine to boil water quickly for many labs, such as a hot water bath.  (Benedict’s solution is used to test sugars in the Biomolecules lab.) (BTW I give graduates an electric kettle and a case of Ramen as a high school graduation gift so they don’t starve to death once they leave home.)  The pipettes are well priced, too.  I recommend 3 mL, graduated pipettes.  Walmart and Amazon are selling a TI 84 graphing calculator for $96.  There are newer TI graphing calculators; the TI 84 does most of the functions.  The chief advantage of a TI 84 over a TI 83 is the EasyTemp thermometer.  It connects to the TI 84 to create a digital thermometer.  EasyTemp thermometers are often available used on eBay.  Easy Data is preloaded on new TI 84 graphing calculators.  Take a look at the LED digital microscopes.  Here is a post explaining how I use digital microscopes in Biology.  Buy these from Amazon or Walmart; both companies make returns easy.  Sometimes the digital microscope is incompatible with the laptop.  I have several brands of microscopes; we just switch brands.  If the digital microscope does not instantly link with your laptop return it.  Amazon sells a single pair of safety glasses for $1.79–hard to beat the price. ( I buy safety glasses by the dozen.  A nerf gun, darts, and pair of safety glasses makes a good birthday present.) BTW the safety glasses and pipettes  aren’t Labor Day deals; usually all of the prices are better Prime Day, Black Friday, and during big sales—like the microscope slides below.  Here’s hoping we can find more deals!

Unbelievable Science Gecko

Five Below has the Unbelievable Science Gecko for….$5!  If your child is squeamish or has sensory issues, consider subbing toys for dissections.   Shipping at Five Below is a flat $8.  Check if the local store has a set or order online and ship to the local store.