This video provides a basic introduction to prokaryotic cells. Topics discussed include: characteristics of bacteria, outer covering, bacterial shapes, key parts of bacterial cells, importance of bacteria and endosymbiotic theory.
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HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on patterns of electrons in the outermost energy levels of atoms. This video gives a quick summary of how to determine the number of valence electrons in the representative elements. These are the elements found in the two left-most columns (below H and Be) and the six right most columns (below B, C, N, O, F and He). Many properties of the elements can be predicted once you know how many valence electrons an atom possesses. Elements in the same vertical column (H, Li, Na, K...) will have the same number of valence electrons which means that they will have similar chemical properties. One exception to this pattern is found in the Noble gases. Helium has only two valence electrons while the other Noble gases contain eight.
PhET is a collection of free simulations covering topics including; math, physics, chemistry biology and earth science. Many of the sims have been converted to HTML5, which means they are BYOD friendly because they will run on iPADs, Chromebooks and phones.
The sims can be run directly from the PhET site or embedded into your own website. The sim below was one that I used as one in a sequence of lessons covering the topic of orbiting objects. Students can choose a number of systems to analyze. The possibilities include; Sun/Earth, Sun/Earth/Moon, Earth/Moon, Earth/Satellite. HS-PS1-7: Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. PS1-7 Evidence Statements The video below discusses the decomposition reaction of hydrogen peroxide and uses a balanced chemical equation and structural formulas to explain why the number of atoms is conserved in a chemical reaction. The video below discusses another example of a chemical reaction and discusses a strategy for writing a balanced equation. HS-PS2-5: Plan and conduct an investigation to provide evidence that an electric current can produce a magnetic field and that a changing magnetic field can produce an electric current. (HS-PS2-5 Evidence Statements) The NGSS performance expectations are basically asking that students re-create the experiments of Michael Faraday. In 1831, Faraday discovered the relationship between electricity and magnetism. His experiments showed that electric currents could be manipulated to create magnetic fields and magnetic fields could be manipulated to create electric currents. I recently had my students compete in an engineering challenge as they worked towards meeting this learning standard. The students really enjoyed having the opportunity to explore the topics of electricity and magnetism, design and build their electromagnets, test them and then finally compete. Students were allowed to use the following materials. Students were allowed to request additional or modified materials as needed.
The competition consisted of two parts. The first challenge required students to activate their magnet and lift as many regular size paper clips as their magnet could support. The second part of the challenge required that students lift a single paper clip at a time and transfer it a distance of 1 meter and drop it into a shoe box without pulling the paper clip off with their hands or "scraping" it off into the box. Groups had 90 seconds to transfer as many paper clips as possible. Groups were given a score for each challenge based on their overall rank, with the top group in each challenge receiving a score of 1. The grand champion was determined by the group that had the lowest point total. This video shows a sample of cesium-137 being tested for emission of radiation. Nuclei of cesium-137 isotopes are unstable and will undergo a process of radioactive decay to form more stable isotopes. Cesium-137 is formed during fission reactions of uranium-235 in nuclear power plants and nuclear weapons. The equation that describes the radioactive decay of cesium is shown below. The conversion of a neutron (from the cesium nucleus) to a proton causes the atomic number to increase from 55 to 56. This leads to the formation of barium-137. It's important to notice that the mass number stays the same in examples of beta decay. NGSS HS-PS3-3: Design, build, and refine a device that works within given constraints to covert one form of energy into another form of energy. For a number of years I taught a 9th grade physical science course that included a unit about engineering. The final project of the unit had students designing, building, and testing trebuchets. The students would compete to see which group could launch a projectile the greatest distance. The competition could be ramped up by adding in an accuracy component as well.
Students learned that the counterweight possesses gravitational potential energy which is converted to kinetic energy when the counterweight falls. The dropping counterweight makes the throwing arm whip around to throw a projectile. This activity takes 2-3 class periods. When I have had to complete this activity in fewer class period I pre-make the throwing arm and we would just switch it from one build to the next during testing. If you have more time I think it makes the activity more challenging for students to need to figure out how to make the throwing arm. There are many options for constraint for this activity. I limited my students to a 1kg counterweight. They were also given set amounts of cardboard, dowel, paper, and had to complete their build within a time limit. The video shown below is from the winning student trebuchet from one of my classes during the 2015-2016 school year at Coon Rapids High School. The materials used for this activity included: -packing tape -cardboard (from cereal boxes) -wooden dowel -paper clips -string -single hole rubber stopper -paper HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties. HS-PS1-2 Evidence Statements The video below shows the example of magnesium reacting with oxygen in a combustion reaction. When magnesium and oxygen react they form an ionic compound. This is due to the fact that magnesium is a metallic element and oxygen is nonmetallic. As an alkaline earth metal (group II) on the periodic table magnesium has two valence electrons it will donate when forming a 2+ cation. Oxygen (group VI) has six valence electrons and will gain two electrons when forming a 2- oxide anion. The magnesium and oxide ions will therefore combine in a 1:1 ratio. The balanced equation for this reaction is shown below. Answer: Paramecium can be found in pond water. Explanation:Paramecium can also be found in brackish and salt water. These protists are single celled organisms. Here is a picture of a paramecium. The video below shows several paramecium feeding. They are using their cilia, which are found all along the outside of the cell membrane, for movement. I hope this helps! HS-LS4-3: Apply concepts of statistics and probability to support explanations that organisms with an advantageous heritable trait tend to increase in proportion to organisms lacking this trait. HHMI BioInteractive video about the Rock Pocket mouse of the American southwest is a great example of how natural selection can cause evolutionary change.
Follow the link below for supporting documents for a classroom activity to support student learning of this topic. Developing an Explanation for Mouse Fur Color Another activity I've used to help students learn this concept is the Evodot simulation created by Jon Herron. Evodot Materials |
Noel PaullerThank for visiting my blog where I post thoughts from the random corner of the universe which is my brain. Archives
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