All Science Definition & Formula Grade 8

Spring Tide

Occurs when new Moon or full Moon are lined up with Earth and Sun; combined gravity gives greatest difference between high/low tides

Quarter moon

One half of the visible moon is illuminated. There are are 2 ___ ___ in the lunar cycle : 1st ___ and 3rd ___

Phase

a point, stage, or part of a cycle.

Speed

Jason rode his skateboard 10 meters in 1 second. This is an example of what (speed, velocity, acceleration) ?

Cycle

an interval of time during which repeated events occur.

subscript

A ___ is written just after and slightly below the element. It identifies how many atoms of that element are present in the compound. If the element has no ___ then it is understood that there is only 1 atom of that element in the compound.

Velocity

A bamboo plant grows 3.75 cm up taller in one hour. This is an example of what (speed, velocity, acceleration) ?

Velocity

A car drives North at 400 kilometers per hour. This is an example of what (speed, velocity, acceleration) ?

endothermic reaction

A chemical reaction in which thermal energy (heat) is absorbed. Also known as cooling.

exothermic reaction

A chemical reaction in which thermal energy (heat) is released. Also known as warming.

Chemical equation

A description of a chemical reaction using element symbols and numbers (chemical formulas)

Acceleration

A downhill skier leans down as she makes a turn down the slope. This is an example of what (speed, velocity, acceleration) ?

Friction

A force that resists (withstands, refuses, opposes) the motion of two surfaces that are touching.

Momentum

A measure of how hard it is to stop a moving object.

Acceleration

A measure of the change in velocity during a period of time. (change in direction, increase speed, decrease speed)

Speed

A measure of the distance an object travels per unit of time.

Revolve

A motion of one object around another object

Waning

A part of the moon's cycle in which the amount of light that is seen decreases each night (half of the cycle).

Waxing

A part of the moon's cycle in which the amount of light that is seen increases each night (half of the cycle).

New moon

A phase of the moon which is completely dark. There is only one ___ ___ in a lunar cycle.

Full moon

A phase of the moon which is completely illuminated (lit). There is only one ___ ___ in a lunar cycle.

Crescent

A phase of the moon which is less than half illuminated (lit).

Gibbous

A phase of the moon which is more than half illuminated (lit).

Force

A push or a pull on an object

Contact force

A push or a pull on one object by another that is touching it.

Non-contact force

A push or a pull on one object can apply to another object without touching.

Chemical formula

A series of symbols and numbers that identify the elements and the numbers of atoms of each element in a compound.

Speed

A snail moves 0.013 meters in 1 second. This is an example of what (speed, velocity, acceleration) ?

Acceleration

A soccer ball rolls to a stop. This is an example of what (speed, velocity, acceleration) ?

Rotate

A spinning motion

Velocity

A storm moves East toward Houston at 30 km/hr. This is an example of what (speed, velocity, acceleration) ?

(final velocity - initial velocity) / total time

Acceleration Formula (meters per second squared)

Acceleration

An airplane slows down at a rate of 3 m/s^2 This is an example of what (speed, velocity, acceleration) ?

Gravity

An attractive force that exists between all objects that have mass.

Circular motion

Any motion in which any object is moving along a curved path.

Total distance / Total time

Average speed formula

Mass / Volume

Density Formula

Kinetic energy

Energy possessed by a body by virtue of (theo, vì, với tư cách) its movement.

*A) Change in Properties* - change in color - formation of bubbles (may indicate gas being produced) - change in odor (smell) - formation of a precipitate (a solid forms when 2 liquids react) *B) Change in Energy* - Warming or cooling - Release of light

Evidence of a chemical reaction

Balanced forces

Forces acting on an object that combine and form a net force of zero.

Unbalanced forces

Forces acting on an object that combine and form a net force that is not a zero.

Velocity

Geese fly about 64 kilometers per hour when they migrate South. This is an example of what (speed, velocity, acceleration) ?

5

How many total molecule in this chemical formula: 5NaCl ?

1

How many total molecule in this chemical formula: HCl ?

Atomic Mass - The number of protons

How to find the number of neutrons ?

Centripetal force

In circular motion, a force that acts perpendicular to the direction of motion, toward the center of the curve.

Decreasing speed

In the distance - time graph, if the line is curved downward, it means the motion of the object in the graph is ___.

Increasing speed

In the distance - time graph, if the line is curved upward, it means the motion of the object in the graph is ___.

Constant speed

In the distance - time graph, if the line is straight diagonal up, it means the motion of the object in the graph is ___.

Stationary (at rest)

In the distance - time graph, if the line is straight horizontal, it means the motion of the object in the graph is ___.

Decreasing speed

In the speed - time graph, if the line is straight diagonal down, it means the motion of the object in the graph is ___.

Increasing speed

In the speed - time graph, if the line is straight diagonal up, it means the motion of the object in the graph is ___.

Constant speed

In the speed - time graph, if the line is straight horizontal, it means the motion of the object in the graph is ___.

Speed

Ms. Baez ran a marathon 26.2 miles in 3 hours. This is an example of what (speed, velocity, acceleration) ?

Neap Tide

Occurs when first or third quarter Moon are at right angle with Earth and Sun; gives less difference between high/low tides

Ellipse

Oval shape

Potential energy

Potential energy is the energy possessed by a body by virtue (theo, vì, với tư cách) of its position or state.

Isotopes

Some atoms of the same element have different number of neutrons.

Distance / Time

Speed Formula

Stationary

Standing still, not moving; at rest

Mass

The amount of matter in an object.

Speed

The cheetah moved at a rate of 3 m/s This is an example of what (speed, velocity, acceleration) ?

Net force

The combination of all the forces acting on an object.

Reactants

The compound (s) that are involved in the reaction. They are on the left of the yield sign (arrow). These are the substance (s) you start with.

Products

The compound (s) that are made as a result of the reaction. They are on the right of the yield sign (arrow). These are the substance (s) you end with.

Valence electron

The electrons in the outermost shell

Weight

The gravitational force exerted on an object.

Perihelion

The point in the Earth's orbit when it is closest to the Sun.

Aphelion

The point in the Earth's orbit when it is furthest from the Sun.

Inertia

The property of matter by which it retains its state of rest or it velocity along a straight line so long as it is not acted upon by an external force.

Acceleration

The runners increase their speed as they near the finish line. This is an example of what (speed, velocity, acceleration) ?

Velocity

The speed and the direction of a moving object.

Instantaneous speed

The speed of an object at a particular moment.

Law of Conservation of Mass

The total mass of the reactants before a chemical reaction is the same as the total mass of the products after the chemical reaction.

23.5

Tilting of the Earth is ___ degree.

Exert

To make a strenuous (hard) effort

Atomic mass unit

What is amu stands for ?

The atomic number is the number of protons

What is atomic number ?

negative -

What is electrical charge of electron ? Symbol ?

neutral (no charge) O

What is electrical charge of neutron ? Symbol ?

positive +

What is electrical charge of proton ? Symbol ?

1st shell

What is k shell ?

2nd shell

What is l shell ?

3rd shell

What is m shell ?

4th shell

What is n shell ?

2N^2 (N is the shell number)

What is the formula to find the maximum number of electrons in an energy shell (level)?

electron cloud (area/religion surrounding the nucleus)

What is the location of electron ?

in the nucleus

What is the location of neutron ?

in the nucleus

What is the location of proton ?

1/1820 ~ 1/2000 amu

What is the mass of electron ?

1 amu

What is the mass of neutron ?

1 amu

What is the mass of proton ?

8

What is the maximum number of electron if the energy shell is the outermost shell ?

perpendicular

When 2 things intersect at right angles or 90 degree angles.

Lunar

relating to the moon

Molecule

the smallest particle of a compound, made of atoms bounded together.

Bonded

to be joined together chemically.

Compound

two or more of different elements bonded together.