A student puts some cooking oil and some water in a boiling tube and shakes it. She then examines it carefully.
The oil and water separate out, with the oil floating on top of the water.
Shaking it harder produces the same result.
Explain what this experiment shows.

The experiment shows that oil is less dense than water

Explanation:

If an object is less dense than water, it will float when placed in water, if an object is denser than water it will sink when placed in water.

The experiment shows that oil is less dense than water and so, the oil and water separate, with the oil floating on top of the water as a student puts some cooking oil and some water in a boiling tube and shakes it.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.  

the answer is symmetrical : )