science 2

what is dark is dark matter and why are scientists looking for it - the unseen matter that provides the mass needed to pull things together, because they want to use it n to prove the Big Bang Theory.

how are operational definitions in science exampled of the models that scientists create of the world - they define a term by setting up tests that the defined concept has to meet. The tests model the concept without actually defining it.

how do particle motion and distance between particles change as a solid substance becomes a gas - they get farther apart

Which kind of vaporization can occur at any temperature between the freezing and boiling points of a substance - evaporation

If a lunar astronaut wanted to know the quantity of matter in a moon rock that he had collected would he want to know its mass or weight - he would want to know its mass because mass is part of density

a glass of milk sits on a table what forces act on the glass of milk - downward force of gravity, and the upward force of the table.

would you do more work lifting a box from the floor to the top of a table or from the floor to a shelf above your head why - You would do more lifting a box from the floor to the shelf above your head because the distance is farther from the floor to the shelf.

which will probably break a pane of glass, a small rock sitting on the glass, or the same rock thrown at the glass why - The same rock thrown at the glass would probably break a plane of glass because it has more force.

energy associated with earbuds - sound

energy associated with a match before its strucks - chemical

energy associated with led on a dvd player - light

energy associated with flashlight battery - electrical

energy associated with stove burner - thermal

energy associated with power plant - nuclear

does the the identity of an uncharged atom change when it becomes an ion explain - yes because it either loses or gains electrons

why is a compound considered a pure substance - it is always made of the same elements in the same porportions.

what is the difference between the molecules of an element and the molecules of a compound - in the molecules of an element, all the atoms are the same, and in the molecules of a compound, all the atoms are different.

which changes in matter can produce an atom different from the original - it is a nuclear change