4th Grade Vocabulary List 1. Adaptation- Something a plant or animal has or does to help it survive in its environment. (Puffer fish, camouflage, hibernation, migration) 2. Cell- The smallest unit of living matter. The 2 major differences between a plant cell and an animal cell is that a plant cell has a cell wall and chloroplasts. 3. Change of State- A physical change of matter from one state to another— solid, liquid, gas. Achieved by adding or taking away heat energy. 4. Circuit- The path along which electrical current flows. For the current to flow the circuit must be closed. 5. Climate- The pattern of seasonal weather that happens year after year. (Memphis has a mild climate all year round.) 6. Weather- The conditions outside at any certain time. (On Tuesday it will be cloudy and Wednesday it will rain.) 7. Complete metamorphosis- A life cycle in which each stage is unlike any other stage. (Egg to Caterpillar to Pupa to Butterfly) 8. Incomplete metamorphosis- A life cycle that has 3 stages of growth: Egg to Nymph to Adult. (Praying Mantis, Damselfly) 9. Concave—Lens that has an inward curved shape. Refracts light. (Sides go in like the trunk of a tree. Remember—go IN a cave) 10. Convex- Lens that bulges out. Refracts light. (Like a football) 11. Discharge- A fast movement of electrical charge from one object to another. (When you get shocked from a doorknob) 12. Electrical current- The flow of electrical charges. (electrons) 13. Static electricity- The build up of electrical charges on an object. (Rubbing balloon on wall. Negative charges build up on the balloon— electrons, and positive charges build up on the wall—protons. They are attracted to each other. Lightning is static electricity. 14. Force- A push or a pull. 15. Friction- A force that works against motion. Slows down and stops objects. 16. Conductor- A material that allows electricity or heat to easily pass through it. “All Aboard!” 17. Insulator- A material that slows or stops electricity, heat or sound. “You better get back!” 18. Light Reflection- When light hits something and bounces off. 19. Light Refraction- When light bends as it travels from one material to another—like air to water. 20. Moon Phases- New—Cresent—First Quarter (Half)—Gibbous—Full— Gibbous—Third Quarter (Half)—Cresent—New. Waxing is when the moon is getting “bigger, bigger, bigger” Waning is when the moon is getting “smaller, smaller, smaller” 21. Erosion- The wearing away of the land by wind and water. 22. Transparent—Clear— Can see through it and light can pass through it easily. 23. Translucent- Cloudy looking. Can see through it a little bit. It scatters the light when it passes through. 24. Opaque- Cannot see through it at all. Completely blocks light so that it cannot pass through. 25. Renewable Resource- A resource that can be replaced. (trees, solar power, wind, vegetables) 26. Non-renewable Resource- A resource that cannot be replaced—once it is used up it is gone. (coal, oil, natural gas—fossil fuels) 27. Rotation- The spinning movement of the earth on its axis. It spins in place. Takes 24 hours. “Rotation gives us day and night.” 28. Revolution- The movement of the earth around the sun. Takes 365 days. “The 2 reasons for the 4 seasons are Revolution and Tilt.” 29. Volume- A measure of how much space an object takes up. 30. Water Cycle- The constant movement of water in various forms between the earth and the atmosphere. Evaporation (water vapor)—Condensation (clouds)—Precipitation (rain, snow, sleet, hail)—Water run-off (Water running into rivers, streams, over the ground) 31. Biodegradable- The ability of a material to decompose naturally by bacteria. ( paper, food, animals, yard waste—dead leaves, grass clippings) 32. Recycle- Making new products from old materials. Materials that can be recycled are: glass, paper, cardboard, metal, plastic. 33. Forms of Energy- Light, heat (thermal), sound, potential, kinetic, mechanical, nuclear, chemical, electrical. Don’t forget about Conversion. That’s when one kind of energy changes to another. Like when you plug in a lamp—electrical energy changes to light energy.