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Homeschooling High School Biology

biology textI did a homeschool biology class the year before I started this blog, but I do have a list of the labs we covered so I thought I would share it for those of you looking to do biology at home.  The textbook we used was Biology: Life on Earth with Physiology (9th edition) (LoE) by Gerald & Teresa Audesirk and Bruce E. Byers.  I used an older edition because it was soooo much cheaper and it was only a couple of  years old.  I really enjoyed this book and learned a lot of biology – my degree is in physics abiology inquiriesnd I hadn’t taken biology since high school!

I did get access to the instructors guide for Biology: Life on Earth and it was pretty good.  You’l see below that I used a lot of the discussion activities and labs from it, they’re all marked with LoE .  I also used some activities from Biology Inquiries: Standards-based labs, Assessements and Discussion Lessons by Martin Shields  (BI) and the book, How to Disssect: Exploring with Probe and Scalpel – Special Projects for Advanced Study by William Berman – I believe that book came with the dissection specimens, but I’m not sure.  I have a youtube playlist with all the videos I showed for this class and probably some I didn’t share with my class.  They are probably in reverse order, if they’re in any order at all, so you’l need to start at the end of the playlist. Some of the photos below are from the middle school biology class that I was teaching at the same time, but that class pretty much followed Real Science Odyssey Biology level 2.

Chapter 1, Life:  Viruses, Alive or Not – lecture activity from LoE instructor guide, basically students are asked whether viruses are alive or not.  This is a topic that is still up to debate.  Students can use their books or the internet try to answer the question.  Discuss.     Is Yeast Alive? (lab I found online).

Chapter 2, Chemistry: Exercise in Chemical Bonding, another lecture activity from LoE instructor guide. Students look up an element that has the atomic number equal to their birth month – born in August, then atomic number 8, Oxygen then fill in a diagram showing the number of protons, neutrons and electrons (in shells) for their atom.  We discussed how atoms want a full outer shell and they see if they can ‘bond’ with anyone else’s atom to make them both ‘happy’.

Chapter 3, Carbon: History of Carbon discussion from Biology Inquiries (BI) and we built molecules with Zometools ( I bought a huge set of these – basically includes all the small sets, from Homeschool Buyers Co-op a few years ago).  I would recommend buying Snatoms now that they have come out.

Chapter 4, Cell Structure: We looked at cheek and onion cells in the microscope and watched the first episode of The Cell by BBC.  Its a great documentary if you can find it.  Here it is on Youtube but its kind of dark.

Chapter 5, Cell Membrane: We did two labs, we looked at red onion cells under the microscope (BI) while putting salt water on the slide – you can watch it shrink! And we did osmosis with eggs which is Lab 5.6 in the LoE instructors guide.  I’ve actually posted about these two experiments before because they were really cool.

Chapter 6, Energy Flow:  Endergonic & Exergonic Reactions, Lab 6.2 from LoE and Lactaid Action Lab 6.3.  The lactaid lab was interesting, we used glucose test strips to test for the presence of glucose in water, milk, sucrose solution, glucose solution, lactose free milk and almond milk.  Then we added lactaid enyzme to each solution and tested it again.  We were surprised to see glucose in lactose free milk before putting in the enzyme and found out that lactose free milk already has the enzyme added to it.

Chapter 7, Photosynthesis: Rate of Photosynthesis leaf disk lab from AP Biology, you can search the web and find lots of variations of this lab.  I believe there were some videos on youtube as well.

Chapter 8, Cell Respiration: modeling respiration with zometools, made glucose and oxygen molecules then took them apart to see how many water and carbon dioxide molecules they could make.  Each group researched a mitochondrial disorder and shared what they found with the class.

Chapter 9, Cell Reproduction: Looked at prepared slides of mitosis and used Pop beads to make stop motion movies of mitosis.  I’ve posted about the pop beads before – they were great for this activity.  We spent a second class on this so students could  make stop motion movies for meiosis as well.

Chapter 10, Genetics:  Did a punnett square activity (BI) where each student chose their ‘pet’ and then bred it with another ‘pet’ in the class and determined the characteristics of the 4 offspring.

Chapter 11& 12 , DNA: Watched NOVA on DNA: Secret of Photo 51,   set up fast plant 72 hour genetics experiment, discussed here and we did a DNA replication activity that I found on the web called Modern Genetics for All Students.  It looks like it might have changed since I downloaded it. Students put together a string of bases (printed out on cardstock) then found the matching pairs, split them up and replicated it so they had two complete strands of DNA.

Chapter 13, Biotech: DNA extraction – some kids did their own spit, some did strawberries.  We also tallied up the fast plant data and looked at the results.

Chapter 14 & 15, Evolution: Gene drift and gene flow exercises with pop beads representing allele. I can’t find the exact source for the lab we did but if you search for gene drift or gene flow and beans you’l find labs using beads or beans. I just used the pop beads since I had them.  Here’s one handout that might be what we used.

Chapter 16, The Origin of Species:  The Lost World activity from BI. Students were given a skull and asked to design an animal. They had to look at the eyes, teeth, etc to figure out what they could about the animal.  They sketched it, took measurements and then drew the rest of the animal as they imagined it.  I happened to have some actual skulls for this activity but you could use photos.

Chapter 17, The History of Life: students made a timeline of life on earth – there’s an activity for this in LoE instructor guide where you print a bunch of cards and students put the events in order then place them on a timeline.  We watched BBC Origins of Us.

Chapter 18, Systematics:  Classifying Oak Leaves (BI), students visually compared three oak leaves and decided if they were separate species.  They made various measurements to support their conclusions.  They were then given three sets of DNA data to compare and used that to decide on the relationships between the oak leaves.

Chapter 19, Prokaryotes, Bacteria & Archae:  Looking at bacteria in yogurt under the microscope and made a virus papercraft.

Chapter 20, Protists: pond water identification with microscope.

Chapter 21, Plants: Walked around the neighborhood finding different types of plants, vascular vs nonvasculat, moss, cycads, angiosperms and gymnosperms.

Chapter 22, Fungi: Found mold, mushrooms and lichens around the yard and looked at them under the microscope.  Lichens are very cool under a microscope, with some you can see the algae inside them.

IMG_6982Chapter 23, Invertabrates: dissected earthworm, sea star and clam – different lab groups did different specimens.  2nd class dissected crayfish and grasshopper and we looked at triops with a microscope.  We also looked at the compound eye of the grasshopper (photo to the right) and wing of a dragonfly with the miscroscope.

Chapter 24, Vertebrates: dissected perch, dog fish shark (which was amazing) and a turtle.

Chapter 43, Plant Anatomy: plant dissection and field trip with local ranger

Chapter 44, Plant Reproduction: pollen tube formation under the microscope, flower and IMG_7562bud dissection.  Students planted African Violet leaves  to grow new plants.  They also took home  cups with corn and bean seeds pressed against the side of plastic cups with a damp paper towel so they could watch them sprout.  I highly recommend looking at as many types of pollen as you can find with a microscope.

Chapter 45, Plant Responses: demonstation of gravitropism – put bean plants on their side in dark boxes and on a window sill, both stems bent as the plant tried to grow upward.  We also had seeds in different positions and showed that the roots always grown down.

Chapter 25, Animal Behavior: Students performed behavior experiments with isopods – see if they preferred dark or light environments,  wet or dry, etc.

Chapter 26, Population Growth & Regulation:  Effects of age at 1st reproduction on population growth (discussion activity from LoE), and we did the Fox and Rabbit game.  You can find many variations of the fox and rabbit game on the web.  I printed out some clipart rabbits and foxes to use.

Chapter 27, Community:  we watched a bunch of videos on keystone and indicator species, each student researched an invasive species and share what they found with the class.

Chapter 28, Ecosystem: Watched videos on food chains, trophic cascade and the effects of wolves on Yellowstone.  We did an activity on the nitrogen cycle and food webs.

Chapter 30, Biodiversity: Watched video on using insects as a food source, Crash Course Ecology #12.  Students had the choice of researching new science inventions and plans for fixing the climate, solving energy or population issues or doing a food chain art project (one of the  middle school student’s project is below).IMG_8563.jpg

Chapter 32 Circulation:  Dissected fetal pigs.

Chapter 36 Defense against Disease: Played You Make Me Sick board game and watched videos on the  immune system. (I couldn’t find the files for the actual game pieces, looks like the website has changed, but the link above has some of the information about the game).

We spent a class or two studying for the Biology SAT, taking practice tests and going over the answers.   For the dissections I watched youtube videos of biology teachers doing it and I have a friend who’s a nurse who helped out.  She really knew what she was doing and was able to do thing like inflate the lungs of the animals with a ‘snot sucker’ and that was really amazing to watch the lungs inflate.

Honors Chemistry 32 – Specific Heat

IMG_0123We managed to plow through this course in pretty good time and the only chapters left in the text are organic chemistry and  since most of the class already did biology with me two years I decided to skip those chapters.  Since we managed to get through all the labs I had planned, I went back and decided to do another specific heat lab from the Home Scientist Chemistry kit manual CK01A, Session IX-3: Determine the Specific Heat of a Metal.  This lab suggests using 25-50 pennies, find their mass and then place them in a beaker with roughly 100 ml of water.  Bring the water to a boil for a few minutes and then measure the temperature (of the hot water and hot pennies).  IMG_0124Remove the pennies from the hot water and place them in a calorimeter (styrofoam cup) containing 100 ml of room temperature water (measure T before putting in hot pennies).  Measure the temperature every 30 seconds until it stops going up.  The heat gained by the room temperature water is equal to the specific heat of water (4.184 J/gK) times the mass of the water (100g) times the change in temperature (roughly 4 or 5 degrees).  Since the heat gained by the water is equal to the heat lost by the pennies we can use the same equation to solve for the specific heat of the pennies.  The students got fairly good results for this lab and it was pretty quick, only took an hour or so.   I happened to have a set of metal cylinders for density labs and some of the students used those instead of the pennies.

That’s it for this class.  I hope you found these posts useful and if you have any questions feel free to post in the comments.  IMG_0122

Honors Chemistry 31 – Nuclear Chemistry

This is one of my favorite chemistry topics since its also a topic in physics.  I pulled out an old slide show on nuclear physics, different types of nuclear reactions, fission, fusion, atomic bombs, power plants, all the good stuff.  We did the activities ‘Simulation of Nuclear Decay Using Pennies and Paper’, from the Modern Chemistry curriculum and built cloud chambers.

For the paper activity,  I precut a bunch of paper strips from colored card stock and gave each IMG_9880student two strips.  They placed the first strip on a graph to represent 100 percent of material.  Half of that will decay in one half life so they take the second strip which is the same length as the first one and cut it in half.  Tape the half strip next to the first one.  Repeat with each remaining strip until you can no longer easily cut the strip.  For this example we made the half life 1 minute, which is about the time it took to fold and cut the piece of paper to make the next bar.

IMG_9881

The other part of this activity involved putting 100 pennies heads up in a box – this represents our ‘original’ sample of material.  Students shook the covered box 5 times and then removed all the pennies that had ‘decayed’ (turned to tails).  This should be roughly half the pennies.  They then repeated the shaking and removing of ‘decayed’ pennies til they had 1 or 0 pennies left.  Every shake was considered to be a half life of 10 minutes for the purposes of graphing their data.

IMG_9892Then we get to the fun part of class, making cloud chambers.  A cloud chamber is a closed container with an isopropyl alcohol soaked felt pad inside it (near the top or sides) and black paper on the bottom.  The alcohol forms a mist inside the container becoming super saturated near the cold bottom of the container which is sitting on dry ice.  As particles zip through the mist it produces ions and the alcohol drops condense on these ions, leaving a visible trail.  There are a lot of videos on the web explaining how to make cloud chambers.  Here are the two I like, one by Jefferson Labs uses a petri dish to make a small cloud chamber and the one on ScienceFriday has instructions for using something bigger.  The petri dish one works really well but its gets fogged up and you spend a lot of time wiping it off.  I bought the dry ice and 91% isopropyl alcohol at my local grocery store. Our best cloud chamber was built from a cheap (thin and flimsy) plastic cookie (Dunkers) container from Trader Joe’s.  IMG_9917

In the photo above you can see our radioactive rock and 4 trails from particles that were emitted from the rock. You can also see the alcohol mist/rain in the container.   You don’t need a radioactive sample to put in the container, you will see trails from muons and other particles that are zipping by us all the time.   Here’s two videos from class:

I asked students to watch these videos before class:

Honors Chemistry 30 – Review lab

We’re almost done with this class and actually finished all the labs that I had previously pulled aside so I spent some time last week browsing the labs that come with the Modern Chemistry homeschool curriculum  and found a few more to try.  Today, we did “How much calcium carbonate is in an eggshell?” from Chapter 15,  Modern Chemistry.  We didn’t get the expected result but its a really good lab and uses a number of concepts including stochiometry and titration.

To start you need a clean eggshell with membranes removed.  Bake in an oven at 110F for 15 minutes – my oven can’t be set this low so  I set it to 160F then turned it off and put the eggshells in the oven for 10 minutes.  Once the eggshells are cool, grind them up to increase surface area.  Put 0.1 grams of powdered eggshell in a small beaker (50ml) and then add 6.0 ml of 1.0M HCl.  The lab handout actually has students figure out the volume of one drop from a pipette and put in 150 drops of HCl into the beaker but since we had pipettes marked in 1/2 ml increments I decided to do it the less monotonous way and just put in 6.0ml.   Students swirled the beaker and watch the reaction.   After 4 minutes, two drops of phenolphthalein indicator were put in the beaker.  Phenolphthalein remains clear for acids and neutral solutions, but turns bright pink in basic solutions.

IMG_9770Students then added 1.0M NaOH solution in 0.5 ml increments into the beaker to neutralize the remaining HCl that did not react with the eggshell.  Both groups ended up putting in 6 ml of the NaOH solution which meant that none of the HCl reacted with the egg shell, which couldn’t be right since we saw a reaction take place (bubbles!).  So we tried again but this time we used red cabbage indicator, which has a range of colors depending on the pH.  The students also used 10ml graduated cylinders to measure the HCl they put in initially and started with 6.0ml of 1.0 M NaOH in a graduated cylinder and slowly moved it to the beaker with a pipette. This way we could just measure the remaining NaOH and know how  much we had put in the beaker.  Unfortuanately we still ended up putting in all the NaOH, only with the last few drops did the indicator record a significant shift in pH.

IMG_9784So then we thought about the titration process and how it was only going to work if the the solutions were both 1.0 M and perhaps we had done that wrong, so we started from scratch and remade the 1.0M solutions from the 6.0M HCl and 6.0M NaOH (These chemicals come in the Home Scientist Chemistry kit)  This time we used the same graduate cylinder to make both solutions.  We used the cabbage indicator and very carefully swirled between drops for the last bit NaOH and found that yet again we had to use almost all the NaOH, 5.6 ml, which means only 0.4ml of HCl reacted.  We went ahead with the calculations and found that our eggshell was only about 20 percent calcium carbonate and the expected number is closer to 80 percent.  I’m not sure what went wrong – did I over heat the eggshell, breaking down the calcium carbonate?  Don’t think so since it really didn’t get very hot.  The eggshells were sitting out on a counter for a few days before we did the experiment (and before heating) so next week I’l have the students  try fresh eggshells.  Perhaps our 6.0M solutions have been contaminated or aren’t quite 6.0M?  Were the eggshells not crushed finely enough?  I’m not sure what went wrong but since this lab didn’t take very long to perform we were able to do it three times and tried to improve the procedure each time.  Blair Lee from SEA Homeschoolers just posted last week about ‘When Experiments Don’t Work, That’s When the Science Really Gets Fun!’, which is exactly what happened today.

Honors Chemistry 29 – Electrochemistry

The labs we did today came from the Home Scientist CKO1A instruction manual which goes along with their chemistry kit.  In Session X-1: Observe Electrolysis there are two labs, in the first one you set up two test tubes full of water (with some epsom salts) upside down in a beaker and then place the wire ends of the battery adapter into the tubes.  Once you connect a battery, current starts to flow through the water breaking it down to create hydrogen and oxygen gases in the test tubes.  We tried to set it up like the lab describes but the battery adapters I bought had short leads and we got pretty frustrated with it.  Luckily I happened to have two electrolysis set ups (see photo below)  that were loaned to us by another homeschool mom.  IMG_9692

The black stand in the bottom of the beaker holds the test tubes in place and the screws are the electrodes, so all we had to do was connect the wires to the battery (after filling the tubes with water).  The other advantage of using this set up is that the test tubes were very small so it didn’t take as long to fill up with gas (though it still took almost an hour).    We skipped measuring the volume of the gas but did notice that one test tube filled up twice as fast as the other because you make 2 hydrogen molecules for every oxygen molecule produced.  The blue arrows in the photo above point to the water level in the test tubes.

While this was bubbling away, I set up the second part of the lab which involved doing electrolysis with salt water.  We took 50 ml of water and a tsp of salt, stirred until it was dissolved and then made electrodes out of Al foil.  We took this lab outside since it produces chlorine gas.  We also put a few drops of phenolphthalein pH indicator in the salt water.  Phenolphthalein is clear in neutral solutions but turns a bright pink in basic solutions.  I hadn’t done this before so I was as suprised as the students when I hooked up the battery and the solution turned pink starting at one electrode and making its way away across the beaker.  The bubbling gas production was also quite vigorous.  We weren’t prepared for how quickly this took place so I had the students repeat it themselves and we took lots of movies and pictures.  If you leave it hooked up for more than a few seconds the Al foil starts to break apart.   When the students did it, the reaction didn’t seem quite as vigorous and that’s because I used a regular teaspoon to put in the salt and they used the chemical spatula which gave them less salt.  Here’s a video of the electrolysis of salt water.

The solution turns pink because sodium hydroxide (a base) is formed along with hydrogen gas at the foil electrode (cathode)  where you first see the solution turn pink.  Chlorine gas is formed at the anode but most of it dissolves into the water.  Very cool little experiment.

I had the students watch Tyler Dewitt’s video on Electrochemistry before class.

He also has this great video which explains exactly what was happening in both labs we did.

 

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