January 2020

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January 30, 2020 3

Big History Science 21 – Fossils

This week we finished up the Big History Project Unit 5. I asked students to watch the following additional videos on paleontology:

The high school class did an activity, “Fossil Teeth: A Record of Climate and Evolutionary Change in the Fossil Record”, which can be downloaded (presentation, worksheet and lesson plan) here and was put together by the National Park Service. This lesson uses real data of fossil teeth found in the Great Plains area of the United States and comes with some worksheets pointing out the different types of mammal teeth and what you can learn from studying a skull. The data shows how the teeth changed over time and leads the students to explore why mammal teeth might have evolved the way they did. We didn’t do all the lessons since we were tight on time but if you’re doing this with your own homeschooler you might take the time to do all the lessons if they show an interest. I happen to have a collection of skulls and fossil teeth so I had them out for students to look at.

For the second part of the class, I provided rough amber and sandpaper so the students could polish the amber and perhaps discover their own fossil (over millions of years old) preserved in amber. I think we had 4 or 5 pieces of amber with preserved insects. One of the pieces I polished had 4 critters, including a spider and grub that I didn’t see until I put the amber under the microscope. I love this activity and have done it many times over the years. I originally bought the Prehistoric Amber Fossil Activity Kit from Nature-Watch.com, which comes with raw amber, sandpaper, denim and bags for the amber, but in later years I just buy the bags of unpolished amber/copal which is much cheaper and buy the sandpaper (a couple different grits) at the local hardware store.

I gave each student a plastic tray to try to contain the mess and had small bowls of water on the table for them to rinse off their amber. Its best to polish the amber wet. Once they have it fairly smooth with the sandpaper they rub it with a piece of denim to get the final finish. They took the denim and amber home so they could keep polishing it if they wanted. I had plenty of amber so those who didn’t find anything in their first piece, could try a second.

2 insects found in amber.

Insect in amber, photographed through a microscope (40X)

The middle school class also got to polish amber but instead of the fossil teeth activity, we took a short fieldtrip to a friend’s house to see their fossil collection. His collection is amazing and he told us about the different plant and animal fossils he found as a kid, and how the fossils formed. He also showed us a bit of a NOVA episode (Bigger than T.Rex – season 41 episode 19) on the Spinosaurus which showed how paleotonologist put together different information to learn about ancient creatures.

Just a small sample of the fossil collection.

Next week we start unit 6.

January 30, 2020 1

Big History Science 20 – Tardigrades

Students were told to look at articles/videos on the Big History Project for 5.3 and the following videos:

Since most of the students in my classes did biology with me last year, I wanted to do something different for the unit on life, so I ordered some tardigrades, aka water bears or moss piglets, from Carolina.com. I’ve tried to find them in moss around my yard but haven’t been successful. Carolina.com has instructions for keeping them alive and I’ve had them almost a week now. We used pipettes to suck up a few drops from the bottom of the container and could easily find 10 or more tardigrades on a slide. We used slides with shallow depressions so the tardigrades wouldn’t be squished. Students also brought moss samples from home and we found a variety of critters but no ‘wild’ water bears.

I also printed out a worksheet that I found on tardigrades at biologycorner.com. Students used their observations through the microscopes and researched tardigrades on the internet to answer the questions.

Below is a movie I made with various video clips taken through the microscope (40X & 100X) with my iPhone and a Celestron NexYZ phone mount. We discovered it was easier to see the tardigrades if we used a flashlight to illuminate the slides from above instead of using the microscope light from below since the tardigrades are fairly transparent.

One of the things I learned about tardigrades this week is that they molt! In the video above you can see the empty outline of a tardigrade and two oval eggs in the cuticle – the spent exoskeleton. We found eggs and cuticles a few times. In the photos and videos you can see their two dark eye spots and the claws on their eight legs. You can also see their stomachs are full of green algae. Tardigrades were a lot of fun to watch through the microscope and I highly recommend ordering some from Carolina.com if you can’t find any.

January 22, 2020 1

Big History Science 19 – How do we know?

Students were asked to read articles/watch videos from the Big History Project 5.2 How Do Earth and Life Interact and take a look at Chapter 25 Astrobiology in Foundations of Astronomy.

We started class with the Big History Project Lesson from 5.0, How Closely Related Are We? Its a simple worksheet where students have to match the percentage of DNA that we have in common with the selection of organisms given. This is a little challenging since it can be difficulted to think about being related to fruit flies and mustard grass.

The main lab activity was the Great Fossil Find, where students played the role of paleontologists on a dig in Montana. There is a script provided to set the scene and a bit of prep work (cutting up paper bones) before class. Each group of 2 or 3 students were given one big envelope with fossil bones and on the first ‘day’ of the dig they found 4 bones and retrieve 4 ‘bones’ from the envelope without looking. They then spend a few minutes trying to guess what kind of animal they might have, is a fish? bird? land animal? The next day they get a few more bones, and so on. After three days they get to compare their find to the other groups and see what bones they might be missing. And finally they get to look through a skeleton resource manual (provided in lesson) and some books on dinosaurs and prehistoric life that I happen to have. The lesson says not to tell them what the actual fossil is since in real life, paleontologist can not ‘look up the answer’ and rarely get an entire skeleton. But I let the students use all the bones at the end and encouraged them to use the internet to see if they could find similiar creatures. This was a great activity and the students were very engaged.

After the Great Fossil Find, we switched gears and talked a bit more about the time line of life on Earth and when it developed. On the poster I have it mentions that the atmosphere of early Earth had very little oxygen and I asked the students, how do we know that? How do we know what the atmosphere was like long ago? We have fossils that show us what plants and animals were around, but how do we know what the air was like? One way we can learn about the history of our atmosphere is by looking at bubbles of air trapped in ice. By looking at the layers in the ice, paleoclimatologists can see how the amount of precipation differed each year (kind of like tree rings), ash layers indicate volcanic activity and bubbles give them information on the chemical make up of the atmosphere at the time they were formed.

Since we had previously discussed the layers of the Earth, we did a short activity on the layers of the atmosphere. I asked the students what happens to the temperature of the air as you go up in altitude and they all said it decreases. Since we can’t measure that directly, we used an interactive, Virtual Ballooning to Explore the Atmosphere on UCAR (University Corporation for Atmospheric Research) Learning Zone website. Students move markers around that indicate where the balloon will take temperature and pressure data. The temperature actually does some strange things as you go up in altitude and this activity lets students discover that for themselves. They have 4 balloons to launch and try to fill in the graph so they can see how temperature and pressure depend on altitude. Once they printed out their graphs they marked and labeled the different layers of the atmosphere and we discussed the altitude for airplanes, ISS, clouds, etc.

The UCAR Learning Zone actually quite a few nice interactives and simple demos and activities related to earth science, its worth exploring a bit.

January 16, 2020 1

Big History Science 18 – Are We Alone?

Students were to look at videos and articles from Big History Project 5.0 & 5.1 over break. We actually started class with the Kessler Science, Plate Tectonics & Continental Drift Escape Room. This was pretty easy to set up, I just had to print out a few puzzles and cut out some pieces. The only thing I had to buy was transparencies for my inkjet, but you could just skip that puzzle if you don’t have them. I only have 10 students so I only made one of each puzzle and three groups solved the puzzles in different orders. I do not have the lock boxes but Kessler has a digital lock form that worked really well. I sent the form to students and once they had the codes they entered them in to see if they got them correct. The first group to get them all correct got their choice of candy prizes.

This was the first time I’ve done an escape room activity and I think it worked pretty good as a review and it was a nice way to start class after a three week break.

For the second half of class, we talked about life on earth, including extremeophiles (such as critters living near thermal events at the bottom of the ocean), the timeline for life developing on earth and finally we discussed the Drake equation and the possibility of other intelligent life existing in our Milky Way Galaxy. All three of these activities can be found on the Night Sky Network Outreach Resources.

Extremeophiles: Life in the Extreme, consists of cards which can be printed from the pdf. Each card discribes an organism that lives in extreme conditions, very hot or very cold, acidic, or dark, or high pressure, etc. Each student was given a card then I asked for everyone who had an organism that likes really hot environments to raise their hand. I asked one of the students to read out loud the description of their extremeophile. I continued asked about different environmental factors and then asked which ones could survive WITHOUT water…. no one raised their hand. All life that we know of on this planet requires water in some form, so when looking for life on other worlds, we are concentrating our search on planets/moons with water.

As an active member of an astronomy club which does a lot of outreach, I was able to get the Earth Timeline/Watery Worlds Banner to use with my class. The Night Sky Network has a pdf so you can print out your own, but they also have instructions on doing this activity without the timeline and just using your out stretched arms, finger tip to finger tip as a timeline, so the banner is not required. The banner (and file) comes with markers describing different points in the evolution of life on earth, first single celled organisms, multicelled organisms, first land animals, dinosaurs, early humans, etc. I passed them out to students and asked them to put them on the timeline. Students that didn’t get one were invited to come up and move the ones already on the timeline if they didn’t think there were correct. Students did a great job and had them all very close to their proper places – on the banner the bottom is folded up to hide the answer so all you do is unfold it when the markers are in place to see if they match.

Lastly, I used the Anyone Out There powerpoint file that explains the Drake equation, which is a thought experiment designed to estimate the number of intelligent civilizations in the Milky Way Galaxy. There is an activity, with cards to print out and pass amoung the students, or you can just go through the questions as you do the presentation. There’s a video on the Night Sky Network page showing how to do the activity or you can watch Carl Sagan explain the Drake equation on youtube.

For homework, I gave the students the Tree of Life Infographic worksheet. They have to use the Tree of Life Infographic on Big History Project 5.1 to answer questions about the domains of different species and how they relate to each other. The infographic is too big and detailed to print easily so its easier for students to use online where they can zoom in to look at different details.

The middle school class did the exact same lessons.

January 8, 2020 1