Answer:
The balloon expands in the number of particles per cubic centimeter decreases. This happens because as it expands there is a decrease in the density of area. The Dead Sea is a solution that is so dense that you easily float on it.
Answer:
Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change.
Explanation:
Answer:
A microwave
Explanation
The human retina can only detect incident light that falls in waves 400 to 720 nanometers long, so we can't see microwave or ultraviolet wavelengths. This also applies to infrared lights which has wavelengths longer than visible and shorter than microwaves, thus being invisible to the human eye.
Answer:A
Explanation:
Given
Skier A takes straight, smooth route while Skier B takes curvy, bumpy route to finish.
We know gravity is conservative in nature i.e. work done against it is independent of path followed
So work done by gravity for A and B is same
According to Work energy Theorem Change in the kinetic Energy is equal to work done by all the forces.
where h=vertical height of hill
thus 
which is same for both A and B
