Earth in Space and Time

Grade 3Mrs. Mullins

Star

• any one of the objects in space that are made of burning gas and that look like points of light in the night sky

Size

• the total amount of physical space that a person or thing occupies

• how large or small someone or something is

Bright

• producing a lot of light• Filled with light

Distance

• the amount of space between two places or things

Emits

• to send out; give forth; discharge

Energy• usable power that comes from heat,

electricity, etc

Remember the types of energy

• Light• Heat• Sound• Electrical• Mechanical• Potential• Kinetic

Light

• the form of energy that makes it possible to see things : the brightness produced by the sun, by fire, a lamp, etc

Heat• energy that causes things to become warmer

Sound

• something that is heard

Breaking the “sound barrier”

Electrical Energy• energy made available by the flow of electric

charge through a conductor

Mechanical Energy

• Mechanical Energy is the energy of motion that does the work. An example of mechanical energy is the wind as it turns a windmill.

• A combination of kinetic and potential energy resulting from the force of gravity or the movement or release of a machine component, such as a spring, clamp, or wheel.

Potential Energy

• energy that is stored within an object, not in motion but capable of becoming active

• Potential Energy is stored energy. Examples of potential energy are oil sitting in a barrel, or water in a lake in the mountains. This energy is referred to as potential energy, because if it were released, it would do a lot of work.

Kinetic Energy

• energy of motion, observable as the movement of an object, particle, or set of particles

• Kinetic Energy is energy that is in motion. Moving water and wind are good examples of kinetic energy. Electricity is also kinetic energy because even though you can't see it happen, electricity involves electrons moving in conductors

Radiant

• Emitting heat or light• Filled with light; bright.

Sun

• A star that is the basis of the solar system and that sustains life on Earth, being the source of heat and light. It has a mean distance from Earth of about 150 million kilometers (93 million miles) a diameter of approximately 1,390,000 kilometers (864,000 miles) and a mass about 330,000 times that of Earth.

Sun

• THE SUN• The sun gives everything on our Earth energy.• The sun is a renewable energy as it is always there. • • Plants need the energy from the sun to grow and

produce food for animals and people. • People and animals then eat the plants and get

energy from the food.

Parts of the Sun

Darker Area (of the Sun)

• These are called the sunspots. Sunspot is a region on the Sun's surface that is marked by intense magnetic activity, which inhibits convection, forming areas of reduced surface temperature.

• Sunspots have a temperature of about 3230°C (5850°F) while the Sun's outer visible layer is called the photosphere and has a temperature of 6000°C (11000°F).

TELESCOPE

An arrangement of lenses or mirrors or both that gathers visible light, permitting direct observation or photographic recording of.

Models

• A small object, usually built to scale, that represents in detail another, often larger object.• physical representation of an object

3-D

• An object that has height, width and depth, like any object in the real world

2-D

• of or having two dimensions, as height and width; lacking substance or depth

Label

• An item used to identify something or someone

Observation

• the act of making and recording a measurement

Approximate

• Close to the actual, but not completely accurate or exact

Gravity

• the natural force that tends to cause physical things to move towards each other : the force that causes things to fall towards the Earth

Newton’s Law of GravityThere is an attractive force between two bodies called gravity. The force of gravity depends on the masses of the two bodies, and their separation (squared); the larger the mass, the greater the attraction; the larger the separation, the smaller the attraction. Note that the word “separation” means the distance between the centers of the two bodies.

F = G m1 m2

r 2

Example of Gravity – a Thrown BallWhen you throw a ball, there are 2 motions: horizontal & vertical.

The horizontal motion obeys Newton’s first law (bodies in motion will stay in motion). The attractive force of gravity causes the upward motion to decelerate, and then change direction. You see the composite of the two behaviors.

Example of Gravity – a Thrown Ball

Example of Gravity – WeightlessnessYou feel weight because of Newton’s third law. Gravity is pulling you down, but the ground is not allowing you to fall. It must therefore be exerting a force on you to keep you from falling. That force is the weight that you feel.

If you were allowed to fall, you would not feel any weight. So when you are in free-fall, you feel weightlessness.

Example of Gravity – WeightlessnessYou feel weight because of Newton’s third law. Gravity is pulling you down, but the ground is not allowing you to fall. It must therefore be exerting a force on you to keep you from falling. That force is the weight that you feel.

As an example, a sky diver is in free fall towards the earth, and therefore feels weightlessness.

gravity

Example of Gravity – Weightlessness

If an object is dropped from rest, it will free-fall until it reaches the Earth.

However, if the object is given a velocity parallel to the ground, the compromise between Newton’s 1st law of motion and gravity will be a free-fall that always misses the Earth, which is an orbit. Because astronauts orbit the Earth in free-fall, they feel weightlessness.

gravity

velocity

Example of Gravity – a Planetary Orbit

Imagine a planet moving sideways with respect to the Sun. Newton’s first law says that it will continue to move sideways. But the law of gravity says that it will also be pulled towards the Sun. The result is a combination motion, in which the planet falls towards the Sun, but misses. This is an orbit.

Example of Gravity – a Planetary Orbit

If the Earth had been born at rest relative to the Sun, it would have fallen immediately into the Sun.

Imagine a planet moving sideways with respect to the Sun. Newton’s first law says that it will continue to move sideways. But the law of gravity says that it will also be pulled towards the Sun. The result is a combination motion, in which the planet falls towards the Sun, but misses. This is an orbit.

Example of Gravity – TidesThe effects of gravity do not depend on the composition of a body, just its mass and distance. The Moon exerts a force on the Earth, but since the Earth has a finite size, this force is different from one side of the Earth to the other. The side of the Earth near the Moon gets pulled most, the center of the Earth less, and the backside least of all. Since most of the Earth is solid, it doesn’t move much, but water reacts to this difference. So we have tides.

d

d

Force

• he capacity to do work or cause physical change; energy, strength, or active power

Please note:

• 10 of the gravity slides were from:• www.astro.psu.edu/users/kluhman/a5/

Lec8.ppt