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Science Term 1 Exam
Prep for 7th grade 1st term exams
Term | Definition |
---|---|
Hypothesis | An educated guess that a scientist believes will occur in an experiment-up |
Control Setup | A part of a good experiment that is used to compare to. It should have all parts of the experiment except for the variable. |
Experimental Set-up | A part of the experiment where we actually test the variable. Same as the control except we add the variable to it. |
Constants | Parts of the experiment and control which are the same. |
Variable | The part of the experiment that you change |
Velocity | Direction and speed of an object. For example 30 mph west |
Acceleration | Any change in an object's velocity. Any time it moves faster and anytime it changes direction. Going around a curve an object accelerates. Speed and direction change |
Speed | Distance / time |
Inertia | Tendency of objects to resist changes in their motion. In other words, objects at rest tends to stay at rest, objects in motion tends to stay in motion, unless acted upon by an unbalanced force Effected by an object’s mass. |
Force | Any push or pull. Forces cause acceleration in the direction of the force. |
Friction | The force that causes objects to eventually stop A force that opposes motion. When something is moving friction acts to slow it down and eventually stop it if no new force is added |
Sliding Friction | Two objects in contact. When one of the other tries |
Rolling Friction | Objects rolling over each other |
Fluid Friction | When something passes through a liquid or a gas |
Issac Newton's Second Law of Motion | Force= mass x acceleration In other word, a causes a mass to accelerate or any acceleration is caused by force |
Issac Newton's Third Law of Motion | For every action there is an equal, but opposite reaction, for every force there is an equal and opposite force |
Pressure | Force that acts on a particular area Pressure = Force \ Area Measured in Pressure per square inch |
Density | Density = Mass / Volume Density is measured in grams per milliliters |
Buoyancy [Buoyant] Force | Force exerted by a fluid upward against gravity |
Archimedes Principle | Weight of the water displaced by an object is equal to the amount of weight loss by the object in the water |
Circulatory System | Organ system that moves gases and wastes to and from cells of your body |
Open Circulatory System | Where blood travels through vessels to vital areas that receive a shower of blood. The blood collects in the bottom of this chamber and returns to the vessel |
Closed circulatory system | Blood is continually contained within vessels and leaves at very small connections to each cell |
Blood vessels | Enough in the body to go around equator 2.5 times |
Arteries | They take blood out from the heart, thickest of the three and are under the most pressure |
Viens | They take blood back to the heart, least pressure The ones you can see |
Capillaries | Thinnest, they are the connectors between arteries and veins and this is when the exchange of material at individual cells takes place. |
Blood | Consists of solid and liquid e.g. Red Blood Cells, White blood cells, Platelets, etc. |
Red Blood Cells | Carry oxygen and CO2 [43% of all blood] |
White blood cells | Fight disease and infection [2% of all blood] |
Platelets | Clot blood when needed [.005% of all blood] |
Plasma | Liquid watery part of blood [55%] |
Internal bleeding | A leak in the enclosed system. The same as a cut on the outside, but it is inside |
Valves | Prevents the backward flow of blood by opening and snapping shut. They make a certain sound when working properly. Lub-Dup. If damaged then a swishing sound is heard. You also have valves in your legs. |
Stroke | When blood doesn’t get to the brain |
Defibrillator machine | Used to shock heart so as to stop the heart from irregular beat. It actually kills the person in order to save the person and return them to a normal rhythm |
Pacemaker | Battery operated device that can send timed electrical impulses to the heart to make it contract regularly |
Circulatory System | Moves blood [heart] Regulates temperature by moving warmer blood at center to outside the back 5 quarts of blood Around 60,000 miles of vessels around the world 2.5 times |
Blood Pressure | Indicates the pressure that blood exerts on the walls of your arteries. High blood pressure is a concern Normal is 120 over 80 Reported by sphygmomanometer [pressure] and stethoscope [listen] 97 over 53 |
Work | Energy transferred through both force and motion. For work to done there must be motion in the direction of the force applied. |
Effort force | What you put in |
Resistant force | What the machine puts out |
Simple Machines | Work will never be reduced Though there is less effort you will have to do the effort for a longer distance or time Simple machines take a small effort and produce a larger resistant force. If they do not then it is a STUPID MACHINE |
Lever | A board or bar that rests on a turning point. This turning point is called a fulcrum. An object that it moves is the load. The closer the object is the fulcrum, the easier it is to move. |
Wheel and Axle | A wheel and axle is actually two wheels attached to each other. One, the wheel is always bigger than the other, the axle |
Pulley | Is made up of a wheel and a rope or chain. The rope fits on the groove of the wheel. One part of the rope is attached to the load. When you pull on one side, the wheel turns and the load will move. |
Inclined Plane | It is a flat surface that is higher on one end You can use this machine to move an object to a lower or higher place. Ramps or slopes that reduce the force needed to lift something. |
Wedge | Used to push two object apart. Is made up of two inclined plane. These planes meet and form a sharp edge. This edge can split things apart. |
Screw | A simple machine that is made from another simple machine. It is actually an inclined plane that winds around itself. It has ridges and is not smooth like a nail. Some are used to lower and raise things. They are also used to hold objects together. |
Mechanical Advantage | The amount a machine helps to do a job. It is calculated using this formula Resistance Force / Effort Force |