4 th Grade Science Review

Transcription

1 4 th Grade Science Review Weather To describe weather scientists measure the four properties of air. They are: 1.wind 2. air temperature 3. humidity 4. air pressure -Air in motion is called wind. -A wind/weather vane tells the direction the wind is blowing. -A thermometer measures how hot or cold the air is. -A rain gauge measures the amount of rain that has fallen. -A barometer measures air pressure. -A hygrometer measures humidity, or water vapor in the air. -An anemometer measures wind speed. Types of Clouds Stratus Description Flat, layered, gray clouds Cumulus Thick, white, billowy clouds Cirrus High, wispy clouds composed of ice crystals Nimbus Large, dark gray clouds

2 air masses front warm front cold front stationary front weather climate air pressure large regions of air that have the same temperature and moisture the boundary between air masses that have different temperatures warm air pushing into a cold air mass cold air pushing into a warm air mass air masses of different temperatures meet and do not move daily condition of the atmosphere average weather in a certain place over a long period of time the force of an area from the push of air

3 Solar System Star: a hot sphere of gases that gives off energy hottest = blue coldest = red Constellation: a number of stars that appear to form a pattern or picture- there are 88! The Sun is the center of our Solar System! It is the largest star in our solar system. It appears brighter because it is closer. *Planets: Inner: Mercury, Venus, Earth, Mars Outer: Jupiter, Saturn, Uranus, Neptune *Gas Giants- Jupiter, Saturn, Uranus, Neptune *Venus is Earth s sister planet *Hottest Planet: Venus *Uranus rotates on its side! *Asteroid Belt: area between the inner and outer planets *List the planets in order from the sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune *Remember our trick: My Very Excellent Mother Just Served Us Nuggets!

4 *What are the differences between inner and outer planets? Inner: closer to the sun, hard, rocky, smaller, hotter more moons Outer: farther from the sun, gas giants, *List the planets from largest to smallest: Jupiter Saturn Uranus Neptune Earth Venus Mars Mercury *Earth: Earth spins on an imaginary line called an axis- A rotation is one complete spin on its axis- It takes 24 hours to make one complete rotation. The Earth revolves around the sun. One complete revolution takes 365 ¼ days (one year). Earth travels in a set path around the sun, called its orbit. Earth s orbit is shaped like an ellipse (a flattened circle). It is elliptical (oval shaped). The tilt of the Earth on its axis causes us to have seasons. It is summer in the northern hemisphere when it is winter in the southern hemisphere. Day and Night are caused by Earth spinning on its axis. *Exploration in Space: Scientists use telescopes to see objects that are far away in great detail. They also use satellites and travel in spacecrafts.

5 Phases of the Moon 1. New Moon 2.Waxing 3. First 4. Waxing 5. Full Moon 6. Waning 7. Third 8. Waning Crescent Quarter Gibbous Gibbous Quarter Crescent

6 Water Cycle What are the three states of water? Solid, liquid and gas How does evaporation occur? The sun s energy heats up water to 212 F or 100 C, it speeds up the particles and makes it change from a liquid to a gas called water vapor. How does condensation occur? Water vapor particles lose heat energy, slow down and condense or change from a gas to a liquid at the dew point. How does Precipitation occur? When clouds become too heavy precipitation falls to the Earth as rain, snow, sleet or hail. When it falls it can land in rivers, lakes or oceans. If it flows over land it is called run-off. Higher than 32 F is rain, lower than 32 F is snow, hail and sleet occurs when the layers in atmosphere are below 32 F. At what temperature in Fahrenheit and Celsius does water turn to a solid? A gas? Liquid to Solid- 32 F or 0 C Liquid to Gas- 212 F or 100 C How much of Earth s surface is covered in water? How much is fresh water? How much is salt water? About 70% to 75% of the Earth s surface is covered in water. 3% of that is fresh water and 97% is salt water. What is the heat energy source in the water cycle? The sun! Explain how the water cycle produces the Earth s fresh water. When water evaporates from oceans, river and lakes, only water particles are evaporated the salt and other impurities remain in the bodies of water. It then condenses and precipitates to Earth as fresh water.

7 Water Cycle Notes evaporation condensation precipitation collection *changing from liquid to gas *molecules are far apart *a water puddle disappearing after the sun comes out *steam coming *changing from gas to liquid *molecules come closer together *water molecules on the side of a cold glass that has an iced drink in it *snow *hail *rain *sleet *water is returned to lakes, oceans, and rivers *rain falling into the lake from a boiling pot *clouds forming in the sky

8 Light light prism wavelength spectrum shadow rays reflection law of reflection refraction lenses convex lens concave lens opaque transparent translucent A form of electromagnetic energy Object that separates white light and bends it into the colors that make it up Distance from the top of one wave to the top of another wave Range of light waves with different wavelengths and energies Places where light does not pass Straight lines that light travels in Takes place when light bounces off a surface at an angle The incoming angle of light is equal to the outgoing angle of light Bending of light Tools that refract light Light rays are brought together at a focal point, bulge in the middle Light rays are spread apart, curve inward Objects block all light and create shadows Objects allow light to pass through them and are things like glass or clear plastic Objects allow some light to pass through and may look blurry *White light is made of 7 colors: ROY G BIV- red, orange, yellow, green, blue, indigo, violet *The closer an object is to a light source, the bigger the shadow *Light coming from above an object creates a shorter shadow than light coming from the side of an object *Convex lenses are used in magnifying glasses, cameras, microscopes, and telescopes

9 SOUND Word sound vibration attributes wavelength frequency pitch amplitude intensity matter solid liquid gas Meaning A form of energy caused by vibrations A back and forth motion started by a form of energy Characteristics or properties of something The way sound travels- like ripples in a ponddistance from one area of sound particles to the next How many vibrations are in a sound in one second The highness or lowness of sound How loud a sound is- how much energy the sound carries Scientifically measurable amount of energy sound carries- related to amplitude A solid, liquid, or gas A form of matter that has a definite shape A form of matter that takes the shape of its container and can be poured A form of matter that takes the shape of its container and is usually invisible

10 *Low frequency sound wave *High frequency sound wave *Without vibrations, we can t hear sound! *Examples of low-pitched sound waves: tuba, cow, drum *Examples of high-pitched sound waves: bird, flute, whistle *There is no air in space, so sound cannot travel without special equipment. *Sound waves move in all directions away from the source. *Echoes happen when sound waves bounce off things. * The decibel is the unit used to measure the intensity of sound. The higher the decibel, the louder the noise is. The lower the decibel, the softer the noise is. *How do we use sound on a daily basis? We communicate with sounds such as talking. We use alarms for safety. Sounds alert us such as bells at school or the beeping of the microwave or washer. *Low amplitude means a quiet sound (not much energy) *High amplitude means a loud sound (a lot of energy)

11 Force, Motion, and Simple Machines o Force- a push or pull o Effort Force- force you use to move something o Motion- movement or change in position o Friction- when 2 objects rub against each other- resistance- rough surfaces cause more friction o Inertia- tendency of an object to stay at rest or stay in motion o Speed- the rate of movement- how fast or slow o Gravity- the force that pulls 2 objects together o Work- to use energy to make something happen o Energy- the ability to do work o Direction- the path of movement- where something is going o Simple Machine- a machine that makes work easier o Inclined Plane- a tilted ramp- to help move things o Lever- a bar or plank and a fixed point (fulcrum)- helps lift heavy objects or open things o Wheel and Axle- a wheel with a bar passing through the center o Pulley- rope is passed around a wheel- makes it easier to lift things o Wedge- two inclined planes back to back o Screw- an inclined plane twisted into a spiral Simple Machines Examples Levers- wheelbarrow, seesaw, shovel Inclined Plane- ramp Screw- light bulb Wheel and Axle- door knob, screwdriver Wedge- ax, knife