This document presents a number of theories, both plausible and implausible or even humorous, for the extinction of the dinosaurs. Links to a glossary are embedded in the text. A reading list and links to related sites are also provided.
This iOS app requires students to use a ten frame to fill in the remaining addend with contrasting chips and then count them to tell how many more to make ten. The app can be set to build sequentially or it can be set to give random values. Additionally, the app includes an option to show number sentences when the problem is complete.
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In this 15 minute video, Mary Holden and her 4th/5th grade class reason about the appropriateness of different computational methods (base-ten blocks, calculators, mental math, or paper and pencil) to specific problems. The video includes a description of how the teacher manages her multi-level class and encourages hands on exploration and discussion in small group learning sessions. At the conclusion of the video are reflection questions for professional development.
Interviewee: Paul Lombardo DNAi Location:Chronicle>Trial of Carrie Buck>outcome Carrie's sterilization in context. Carrie's one-hour sterilization took place in 1927, the same year that Babe Ruth hit 60 home runs and Charles Lindbergh flew solo across the Atlantic.
3D interactive model of 1H-pyrazole C₃H₄N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1H-pyridine-2-thione C₅H₅NS for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1H-pyrrole C₄H₅N for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1R_2S-1_2-diaminocyclohexane C₆H₁₄N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1R_2S-1_2-dimethylcyclopentane C₇H₁₄ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1R_3S-1_3-dimethylcyclopentane C₇H₁₄ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1R-camphene C₁₀H₁₆ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1R-camphor C₁₀H₁₆O for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1S_2R-1_2-diphenylethane-1_2-diol C₁₄H₁₄O₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1S_2S-1_2-diaminocyclohexane C₆H₁₄N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1S_2S-1-ethyl-2-methylcyclopentane C₈H₁₆ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1_10-phenanthroline C₁₂H₈N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1_1_1_2_2_2-hexafluoroethane C₂F₆ for demonstrating molecular geometry, vibrations, symmetry and orbitals.
3D interactive model of 1_1_1_2_2-pentafluoroethane C₂HF₅ for demonstrating molecular geometry, vibrations, symmetry and orbitals.