Grade 2 students explore the school yard with thermometers, looking for the hottest and coldest places. They hang weather bags full of colored water outdoors in the sun and shade to compare local variations in temperature. Students discover that weather bags on the north side freeze more readily than bags on the south side of the outdoor classroom. Students construct an explanation for this phenomenon, using evidence and reasoning to support their claim.
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Lots of grasshoppers are around when school opens in August. Students catch them and show them to me. Have you ever tried to catch a grasshopper? It's hard to do! Why is catching a grasshopper so hard to do? We looked closely at the grasshopper's body and observed its behaviors. We recorded observations in our science notebooks. We think grasshoppers are green so they blend into their environment. And, they have super strong back legs so they can jump away from predators. To test our ideas, grade 2 students investigated camouflage using colored toothpicks to represent grasshoppers. When teacher hid 300 colored toothpicks in the grass (50 of each color), we only found 18 of the 50 green toothpicks! Working in small groups, we graphed our data. Then put all the data together to make a class graph. We used this data as evidence to support our claim that camouflage really does help creatures hide from predators. How do other creatures defend themselves against predators? Students did some research to find out (see Ranger Rick magazines). They posted creature defenses on sticky notes on a class chart. We reflected on all the many different ways nature has solved the problem of defense. So many different creatures, so many ways to defend!
Today we are sky watchers looking for weather patterns! Students have created a weather station and have been recording data in their science journals. Our weather station includes a rain gauge, thermometer, and a wind vane in the form of our turbine. We also hung "weather bags" full of colored water. We are using them to investigate water molecules. We want to find out how cold it has to get to freeze water. The weather has been unusually warm this year. No sign of snow yet! But the first day of winter is approaching, and we are hopeful. We check our weather bags every day to see if they are liquid or solid. We have also been drawing the clouds we see in our science journal. There have been so many different kinds of clouds! Some days we even see the moon in the daytime sky! We are curious to know how water changes from a liquid to a solid then back to a liquid again. We are also curious about snow. Is snow a liquid or a solid? We will keep thinking! Water molecules We learned about Wilson "Snowflake" Bentley, a scientist who studied snowflakes. He looked at thousands of snowflakes, and took photos of them on a camera that he attached to his microscope. He published his snowflake photos in a book. He said it was his gift to the world. He discovered that no two snowflakes are alike! We looked at Bentley's photos to compare the different snowflakes. We noticed that all the snowflakes have six points, and a hexagon shape in the center! The form and detail of each snowflake is unique. We drew some of Snowflake Bentley's snowflakes in our science journals. Snowflakes are so beautiful! Read more about Snowflake Bentley in this Caldecott award-winning picture book.
Week 1 I met students in the outdoor classroom for our first science lesson. I explained that science is everywhere, and that today we were going to see if we could find science happening right in our school garden. I reminded them that when we think like scientists, we look closely. So, first we are going to make observations of the garden from a distance. Then we are going to see what we can discover when we look closely. From afar students could see sunflowers bending and drooping. We used our bodies to show how the sunflowers were bending and drooping. Then I passed out magnifying glasses to each student, and let the exploration begin. When students looked closely, they discovered seeds inside the flower heads and a whole community of organisms. They discovered ants, bees, wasps, slugs, and a ton of ladybugs at all different stages of their life cycle (egg, larva, pupa, adult). One student noticed that the undersides of the sunflower leaves were covered in tiny white spots. Students debated about what the spots were. Some thought it was dirt. Others using a hand lens claimed the spots were tiny bugs. We added the question to our question board: What is the white "stuff" under the sunflower leaves? We also noticed that some of the sunflower leaves had major holes! Who is eating the plants in our garden? Students recorded their observations and discoveries in science journals. On one side of the paper they recorded what they could observe from far away, and on the other side what they discovered when they looked closely. They were amazed at how many things they could discover when they looked closely! Week 2 Back in the classroom, we did some research to find out which insects are good for our garden, and which insects are bad. We discovered that ladybugs are really good for our garden. (They eat the bad bugs.) And, we discovered that aphids (the "stuff" under the leaves) are really bad for our garden. They suck plant sap, turning leaves yellow and killing the plant. Why are there so many aphids in our garden? Can the ladybugs rescue our sunflowers? To further investigate the aphid population in our garden, we played a game of tag. Students (acting as aphids) went looking for habitat components (other students pretending to be food, water, or shelter). If the aphids found the resource they were looking for, they tagged it and the resource became an aphid. If the aphids did not find the resource they were looking for, they died and became part of the habitat. After each round of tag we collected data, recording the number of aphids in the population. The following week, we graphed the results. We noticed that when resources were plentiful, the size of the aphid population went up. When resources were scarce, the size of the aphid population went down. Mid-way into the game, we added a ladybug predator. (See the arrow at the top of our graph.) With the advent of the ladybug, the aphid population size began to decline and eventually stabilized. Maybe there is hope for our sunflowers! Week 3 Now that we knew something about aphids and ladybugs, we were curious about what all the other creatures were doing in our garden. How do all these creatures interact to form an ecosystem? It turns out ladybugs are not the only ones that depend on aphids. Ants depend on aphids too. Except that ants don't eat aphids, they milk them for "honeydew" (i.e., eat aphid poop). In return for the honeydew, ants protect the aphids. Ants will attack any ladybug that tries to eat an aphid. We decided to make a classroom model of our garden ecosystem using yarn, and we saw how everything is connected. The sun gives energy to the sunflower, the bees depend on the sunflower for nectar and pollen, the aphids eat plant sap, the ladybugs and wasps eat aphids, and the ants farm the aphids for honeydew. Then I had a sad announcement to make. Scientists believe ladybugs in America are going extinct. The American nine-spotted ladybug has rarely been seen in the last decade. Exotic species of ladybug, brought to the U.S. decades ago to fight aphids, have taken over the former range of the nine-spot. What will happen if the nine-spot goes extinct? It is difficult for scientists to predict. We had our classroom ladybug tug on her string to see how many creatures might be affected by her loss. Then she let go of her string. What happened? When the ladybug in our classroom food web disappeared, it impacted every other organism in our ecosystem. Our food web eventually collapsed. This is a big problem! We needed to think like scientists! (Because scientists solve problems.) After doing some research, I found out that scientists at Cornell University in New York are working to solve this problem. And they need our help! They have asked us to look for ladybugs and photograph them (especially if we find the rare nine-spotted North American ladybug). We can submit our ladybug photos to an online database to contribute to the study. Students were eager to participate in this citizen science project. (See the Lost Ladybug Project or Lost Ladybug App to learn how you can help too.) To prepare for our search for the lost ladybug, we learned how to identify different species of ladybug. We reviewed ladybug anatomy, and drew a picture of the nine-spotted ladybug for our science journals. Then the search was on! Week 4 When we returned to the school garden this week to search for the lost ladybug, the children immediately noticed how much the sunflowers had changed. The leaves with aphids on the undersides had now turned yellow and mottled. It's amazing how much damage a tiny aphid can do! Every student hurried about the garden looking for ladybugs and counting their spots. Each one was hopeful that they would find a nine-spot. We had a couple close calls in which an excited student would begin to shout, and friends would gather around to count the spots. But we soon discovered that all the ladybugs in our garden were the Asian or European varieties. This did not deter the students; they were not discouraged. They were just excited to keep looking at home. We submitted the three photos below to the Lost Ladybug Project. Each photo depicts a different species of ladybug we found in our garden, Hippodamia convergens, Harmonia axyridis, and Coccinella septempunctata. (Photos and data we submitted to the Lost Ladybug Project can also be found on the contributors' page here.) At the end of our ladybug search, we celebrated our learning with a harvest. Students enjoyed eating sunflower seeds, and all the students wanted to save a few seeds to take home. One student told me that he wanted to plant sunflowers at home so he could keep looking for the lost ladybug. (This made me so happy!) After the harvest, students worked together to create a mural of the sunflowers and ladybugs in our garden. We revealed the mural at our Fall Family Science Night. Students were excited to share what they had learned with their parents. That completes our science in the garden. But we will keep looking for the lost lady bug! I am so proud of our young citizen scientists! The ladybugs and sunflowers in the garden also inspired a lot of other art work in the first and second grade. The halls of the school are now filled with sunflowers and ladybugs. Below are some samples of the students' work. Enjoy!
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November 2015
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