Science mid term

• Kilo, Hecto, Deka, Deci, Centi, Mili
• (King Henery Died by drinking Chocolate Milk)

Accuracy means getting a result that is close to the real answer. Precision means getting a similar result every time you try.

• The
• ability of a material to be drawn into wire.

• Father
• of atomic theory

• gravitational force,
• electromagnetic force, strong force, weak force

• D = m/vSo g/ml for liquids and irregular solids
• and g/cm3 for regular solids

An experiment in which all of the variables are controlled by the experimenter.

The ability of a substance be hammered into sheets.

Alkali metals

Low density, silver/white metal, very soft, highly reactive

Alkaline Earth Metals

• Higher densities than alkali
• metals, silver in color, very reactive but not as reactive as alkali metals

0.5 kl

• Since water has a density of
• 1g/ml than it will sink in water. If it
• is in a substance like mercury that has a density of 13.5 g/ml, it would float
• in mercury

A balloon taken outside on a cold day would shrink in volume. The reason is because as the air in the balloon (helium) lowers its temperature to match the outdoor temp, the lower temperature causes the volume of the helium to decrease. The volume of a gas is directly proportional to its temperature.

• They are
• broken and new ones are formed.

• No, they have a full shell
• of valence electrons which makes them unreactive.

• A triple beam balance to measure mass, ruler (to measure length width and height of a regular solid, and a graduated cylinder to measure liquids and irregular solids
• volume.

The amount of solute compared to the amount of solution.

It will be negative if it gains an electron.

Forms as a solid during a chemical reaction of two liquids. It will fall to the bottom due to its higher density than the liquid it is in.

5 g/ml

Mass is what everything is made of. The more mass an object has, the more inertia it has. Inertia is the ability of an object to resist a change in motion.

Raise the temperature, stir the solution, and or break the solute into smaller pieces.

Production of a gas, heat, light, fizzing, bubbling, color change, fire, smoke, odor change

JJ Thomson

Happening at regular intervals

because they have full shell of valence electrons which makes them un-reactive

Element – silver, iron, silicon, etcMixture – chocolate chip cookie, granite, kool-AidCompound – carbon dioxide, water, ammonia, salt, etc.

A solute is dissolved in a solvent. There is usually more solvent than solute. The solute is a solid and the solvent is a liquid.

Discovering the positively charged, densely packed nucleus

Dmitri Mendeleev

It determines the reactivity of an element.

The smallest particle of matter that still retains properties of a substance.

Atoms are the smallest particle of matter. Molecules are made of two or more atoms. All molecules are made up of the atoms of two or more elements.

AMU

Boron, Silicon, Germanium, Arsenic, Antimony, Tellerium

Water (H2O), or oxygen we breathe (O2), many more…

Democritus

The number of protons and electrons.

proton and neutron – inside the nucleus, electron – outside the nucleus

Group 17

A new substance with new properties is formed. The identity of the original substance has been changed.

groups

Periods

Average speed = d/t

Centripetal acceleration

Gravity

An object in motion will stay in motion and an object at rest will stay at rest unless acted on by an unbalanced force.

roughness of the surface and the weight of the object

Average speed = d/tAv Sp = 50m/10 sAv sp = 5 m/s

A force is a push or a pull on an object and it is measured in Newtons (N).

Inertia is the property of an object to resist a change in motion. The more mass an object has the more inertia

The gravity constant or the acceleration due to gravity of a falling object. On earth an object will fall at an acceleration of 9.8 m/s2. This means for each second an object falls, it will increase its velocity by 9.8 m/s.

Speed in a particular direction

Static friction and kinetic friction.

The mass of an object is a measure of how much matter is in an object. This cannot change no matter where an object is (in the universe). Weight is a measure of gravity’s pull on an object. The weight of an object will be determined by the gravity of the moon/planet that an object is on. The mass of an object cannot change but the weight of an object can, depending on its location. This is why we have the same mass on earth and the moon but we weigh less on the moon.

The more mass something has the more inertia it has

The change in velocity over time.

Answers vary but helpful friction is explained as friction that works to make something do what we want it to do. Car tires need friction to stay on the road. This is helpful. Inside a car’s engine, friction is breaking the metal pistons down as they rub together creating excessive heat and mechanical break down of engine parts. This is harmful friction.

Where there is no influence from air resistance, so technically, any place that has no air. The moon and space are examples.

For every action there is an equal and opposite reaction. It also states that all forces act in pairs.

Acceleration or positive acceleration and deceleration or negative acceleration.

Gravity is a measure of the force between two objects that have mass. It is measured in Newtons.

Vertical acceleration (imparted by gravity) and horizontal motion (given to object at the beginning of its journey).

Answers vary but playing pool (billiards) is a good example of Newton’s 3rd Law. When one ball hits another ball, the ball being struck imparts and equal and opposite force to the ball doing the striking, thus allowing it to be “pushed away”.

V = d/t (in a particular direction)

V = gxtV = 9.8 m/s2 x 7sV = 68.6 m/s

It impedes the acceleration of an object as it falls. It essentially gets in the way and creates a force that works against gravity’s pull.

The maximum velocity that is reached when an object accelerated due to gravity on earth. An object should never stop accelerating as it falls towards the earth but the air resistance eventually pushes back with enough force to keep the falling object from accelerating anymore. Objects that have an atmosphere will have a terminal velocity. Planets and moons with no atmosphere will not have a terminal velocity

The sum of all the forces acting on an object

Newton’s 2nd law of motion says that there is a relationship between the mass, acceleration, and force applied on an object. Or said another way, the acceleration of an object will depend on the force applied and how much mass it is.F=ma

• Forces traveling in the same
• direction are added together to find the net force while forces traveling in
• opposite directions are subtracted from on another.

Force, mass, and acceleration

A balanced force is one in which no net forces result on an object. If there are no net forces then an object cannot change its current motion. If it is moving it will stay moving. If it is at rest it will stay that way unless it is acted on by an un-balanced force.

The transfer of energy to an object by a force that results in the object moving in the direction of the force.

Answers vary but, if you want to accelerate more as a runner, you can run harder (add more force) or lose mass (lose weight).

An unbalanced force is a force that is not cancelled out by an equal and opposite force. A positive net force is created which allows an object to change its motion.

W = F x d

Acceleration = (final velocity-starting velocity)/ the time it takes to change velocityORAcc = (VF – VS)/ change in time

Friction is an unbalanced force that creates change in the motion of an object.

Newton meters or joules.

Knife, plow, cleats (on sports shoes), etc.

Momentum is dependant on the mass of an object and its velocity. An object that has a lot of momentum will be difficult to stop. In other words, the more mass and velocity an object has (momentum) the harder it is to stop. Would you rather try to stop a bike or a car? Generally a car will have much greater momentum because of the large mass difference. A bike would have to go ridiculously fast to have more momentum than a car. Certainly a person riding a bike would never be able to go fast enough to account for the smaller mass of a bike versus a car.

Power is the rate at which work is done.

A wood screw, cork screw (wine bottle opener), a jar lid

Cars tires, door knob, etc.

The ability to do work.

Wheel chair ramp, stairs, etc.

potential energy and kinetic energy

• gravitational potential energy
• GPE = weight x height

Energy conversion is energy going from one form to another. For example, sunlight (light energy) travels to the Earth and hits a road (asphalt). The road becomes warm, or said another way the light energy converts into thermal energy (heat).

Perpetual motion is not possible because some energy is “lost” due to the internal friction of the moving parts of any machine. We can try to reduce the friction in a machine but you can never remove all of it. Consequently, some mechanical energy is converted into thermal energy (heat) due to the friction of parts that are in contact with one another.

A law tells us how things work. A law is more of a summary of data and observations.A theory explains how and why something happens. It is more of an explanation of the data and observations.

A chemical property tells us what a substance CAN DO while a chemical change is what a substance DOES DO. Also:A chemical property predicts how a substance will react while a chemical change tells us how a substance reacted.

A machine

Odor change, smoke, fire, color change, production of a gas, fizzing, bubbling, heat, light, etc.

None, these are all physical properties.

• Mass: triple beam
• balance

• Weight: spring
• scale

• Colloid: mayonnaise, toothpaste, jello
• Suspension: snow globe
• *Note: A suspension can have solid particles large enough to be trapped in a filter while a colloid’s particles are too small to be captured by a filter.