According to Merriam-Webster, the definition for silence is:

A good scientist should possess the following qualities:

1. A scientist must be curious about the world Example: Galileo Galileo's curiosity about the heavenly bodies made him the first person to use a telescope to study the moon, the sun, the planets and the stars.

2. A scientist is logical and systematic Example: Among the reasons why Gregor Mendel discovered the principles of heredity when others have failed was his logical experimental methods and his careful and accurate record keeping.

3. A scientist is open-minded and free of bias Example: An open-minded person is one who can modify plans or discard hypotheses if necessary. One such person was Johannes Kepler who was hired to develop evidence that planets moved along perfect circles.

4. A scientist is intellectually honest Example: Isaac Newton built his laws of motion on the previous work of Galileo and others.

5. A scientist works hard and is persistent Example: Marie Curie was the first person ever to be awarded the Nobel Prize twice. It was not surprising considering how hard she worked.

6. A scientist does not jump to conclusions Example: John Dalton's atomic theory was backed by experimental evidence. He was not the first to propose that the atom was the smallest particle of matter, but he was the first to use experimental evidence to support his theory.

7. A scientist is a creative and critical thinkerExample: Albert Einstein was able to derive his theory of relativity because he went beyond what was given and known at that time. He saw links and connections where others did not. He looked at things from different perspectives.

8. A scientist is rational

9. A scientist is willing to suspend judgment until he is sure of his results

10. A scientist tries new approaches to arrive at solutions

In addition:

A scientist must have an open mind and be curious. It is fine to have an idea about how or why something is the way it is, but the scientist should then seek to prove or disprove this "hypothesis" and should then be willing to change their ideas depending on the results of their experiments, rather than to continue believing in their original idea even if the evidence of their experiments is sticking up against it. 1.Keen Observer 2.creative 3.patient 4.curious 5.humble 6.intellectually honest 7.objective 8.Aware of the limitations of Science 9.Persevering 10.Open minded

Physical Changes

• Change of state (such as from solid to liquid or from gas to liquid)
  • Specific examples of state change include water freezing, alcohol evaporating and dry ice (solid carbon dioxide) subliming
• Absorption of water into a towel
• Crumpling a piece of paper
• Pulling copper into a thin wire - a change of shape, but not a change of composition
• Cutting a material such as wood
• Tearing a piece of tin foil
• Breaking glass
• Deflating a basketball
• Mixing different solids (such as solid sulfur and iron filings)
• Inflating a volleyball
• Cloud forming in the sky

Chemical changes

• Burning a log of wood
• Mixing an acid with a base, producing water and a salt.
• Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants.
• Cracking heavy hydrocarbons to create lighter hydrocarbons (part of the process of refining oil).
• Cooking examples: popcorn, cake, pancakes, and eggs
• Oxidation examples: rust or tarnishing
• Combustion
• Mixing chemicals
• Rotting of fruit
• Cooking rice
• Explosion of fireworks
• Tarnishing silver
• Lighting a match
• Chewing/digesting food
• Rusting nail
• Burning gas in a stove
• Oxidizing food for energy
• Roasting a marshmallow
• Adding food coloring to icing
• Frying an egg
• Burning a magnesium strip

The following can indicate that a chemical change took place, although this evidence is not conclusive:

• Change of color (for example, silver to reddish-brown when iron rusts)
• Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat
• Change of form (for example, burning paper)
• Light, heat, or sound is given off
• Formation of gases, often appearing as bubbles
• Formation of precipitate (insoluble particles)
• The decomposition of organic matter (for example, rotting food)

First, scientists are pretty sure the Earth's core is about 80 percent iron. How they know that is a series of educated guesses.

For starters, they can be reasonably sure of the planet's mass based on its gravitational pull. The material on the surface isn't dense enough to match up with that mass, so the rest of the Earth has to be much denser.

It's a lot more scientific than I've made it sound, but hopefully that gets at the gist of it.

Physical Change:

*Milo dissolves into hot milk

*A plate is dropped and shatters

*Grass in mowed

*Metal Knife is sharpened

*Breakfast Cereal goes soggy

Chemical Change:

*Wood burns to form black charcoal

* A green tomato ripens and turns red

* Fireworks explode to form colourful light and loud sounds

* Vegetables scraps in the compost bin decompose to form rich soil

* An egg is cooked to become a white and yellow solid