Flash Cards

7th grade Overall science

Term Definition
The number of _______ in an atom determines the type of element you have. Protons
What are the elements in the periodic table arranged according to? Their atomic number
What kind of element are most of the elements on the periodic table? Metals
What is a characteristic of Transition metals? They are conductors of electricity and heat
If two charges repel each other, the two charges must be… Like charges
How does an object become charged? When the atom gains or looses electrons
What is static electricity? Electric charge that has built up in one place
What is an insulator? A material through which electrons don't flow easily
A positively charged object has… More protons than electrons or neutrons (when it looses electrons)
A magnet attracts to objects containing… Iron
On a bar magnet, which side would attract to the North side on another magnet? The south side of the magnet
In a battery, the energy is usually stored in the form of… Chemical Energy
What is PE? Stored energy
The thermal energy of a substance changes the ______ energy of its particles Kinetic
In every energy conversion, some energy is always converted into… Thermal energy
What does gravitational potential energy depend on? Height and weight
What does kinetic energy depend on? Mass and velocity
What energy conversion is taking place in a green plant in sunlight during the process of photosynthesis? Light -> Chemical -> Thermal
What sequence of energy transformations occurs after a battery operated flashlight is turned on? Chemical -> Electrical -> Light -> Thermal
After an energy conversion, you end up with the same total amount of energy as the original amount of PE. What law explains this rule? Law of Conservation of Energy
What is the density of water? 1g/mL
Which unit do you measure mass in? Grams
What is the standard unit of length? Meters
A student measures the mass of an empty graduated cylinder as 42g, she then measures a graduated cylinder filled with water and finds it has a mass of 62g. What is the mass of the water? 62-42=20g
In a graduated cylinder containing several liquid layers, the least dense liquid is found… On the top
If you have 150g of pure gold and the entity of the gold is 19.32g/cm cubed, what is the volume of your gold nugget? V= M/D
V= 7.8cm cubed
What is the best way to measure the volume of an irregularly shaped solid? Doing the water displacement method
What happens to a solid object with a density that is less that water when it is placed in water? It floats
What is the solute? The substance being dissolved in a solution
What would be the best method in separating sand and iron? Using a magnet
What can you do to dissolve sugar fast? Crush it, heat up the water, or stir the water with the sugar
If a spoonful of salt is mixed into a glass of water, what is the water called? A solvent
What is the compound made by plants during photosynthesis? Glucose
Melting crayons is an example of what kind of change? Physical change
What chemical property is responsible for iron rusting? Reactivity with Oxygen
Malleability is and example of what kind of property? Physical
What is a compound? A pure substance that is made up of two or more chemically combined elements
Boiling point, melting point, and density are examples of an element's… Physical properties
By what process can compounds be broken down? By chemical changes
What happens to the properties of the different components of a mixture win materials combine? They stay the same
What is velocity? The speed of an object in a particular direction
To find the average speed of an object what do you need to know? Total distance & total time
A child on a merry go round is accelerating because the child is… Changing direction
If the mass of an object increases, the weight of the object will… Increase
Brakes in a bike work by pressing brake pads together on the rim of the wheels. The pads rub together and slow the bike, this is due to… Friction (sliding friction)
What is the speed of an object that covers 400km in 5 hrs? S=D/T
The wheels and gears of a machine are greased in order to decrease… FRICTION
Why does friction occur? No surface is completely smooth (there is always hills & mountains)
What would happen to your weight if you went to the moon? You would weigh less because there is less gravity
An object in motion with no unbalanced force acting on it will… Stay in motion
If the force acting on an object increased and mass stayed the same, acceleration would.. Increase
What force causes a leaf to fall more slowly than a penny? Air resistance
All objects resist change in motion. This is the law of… Inertia
The statement "to every action there is an equal and opposite reaction" is: Newton's Third Law
When two objects collide, the momentum of the pair after the collision is explained by: Newton's Third Law
The shape of the path of a projectile motion is… Curved
What is a screw? An inclined plane wrapped around a cylindrical pole
The amount of work done by a machine is never larger than the work put into a machine because some of the input work is lost due to… Friction
Levers are divided into classes based on the location of their… Fulcrum, load (output) and effort (input)
When a soccer ball is kicked, why don't the action and reaction forces cancel each other out? The forces don't work on the same object.
Your acceleration increases as the force acting on you… Increases
The Moon's gravitational force has a greater affect on the ocean tides of Earth than the Sun's gravitational force. What is the reason for this? The moon is closer to the Earth than the Sun. As distance increases, gravity decreases (indirect)
What does the force of gravity depend on? Distance and mass
During which two changes of state do atoms or molecules become closer together? Freezing and condensation
Dew collection on a spider web is an example of what? Condensation
Which changes of state of water both occur at 100 degrees Celsius? Boiling and Condensation
What is sublimation? When a solid changes directly into a gas.
What best describes the particles of a solid? Vibrate in place and close together
Is liquid freezing endothermic or exothermic? Exothermic
What would happen to a balloon when you walk outside on a cold day? It will deflate. Charle's Law, as temperature decreases, volume decreases, direct relationship
What will happen to a gas when pressure decreases? The volume will increase. Boyle's Law, as pressure increases, volume decreases, indirect relationship.
Which substance has particles close together but slide past each other? A liquid
Which state of matter has definite shape and definite volume? A solid
During which three phase changes os heat energy absorbed by a substance? Melting, boiling, and sublimation
What is the reverse of condensation? Vaporization
According to Charle's Law… As temperature increases, volume of a gas increases
According to Boyle's Law… As pressure of gas increases, volume decreases
During which change of state do atoms or molecules become more ordered? Freezing
What is a plasma? A gas-like mixture with a volume and a shape that changes that is made up of charged particles (ions)
As a sample of matter is heated its particles, Move faster
What is the fixed point in a lever? The fulcrum
What are the three ways a machine can make work easier for you? 1) Change side of force
2) Change direction of force
3) Change distance the force is moved
What does a fixed pulley change? The direction of force
How does using a ramp make lifting a heavy object easier? YOu use the same amount of force but over a large distance.

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