What Are Cells?
Cells are the smallest structures that can perform all the processes required for life. All cells share certain components. They have a membrane that covers their surface, separating them from their environment, and controlling what enters and leaves the cell.
Cells also all have organelles, which are constructions inside cells that perform specific functions. Additionally, cells contain genetic material for at least some period during their existence. This genetic material manages the activities of a cell, and it's passed on from parent cells to new cells.
Cell theory states that the cell is the basic unit of all living things, all organisms are composed of one or more cells, and all cells come from existing cells.
What Is Chemical Bonding?
Once formed, these new substances have properties different from those of the original atoms' elements'. The atoms of over one hundred different elements connect in a variety of combinations to form the substances in our universe.
What Is Pressure?
Pressure is a force applied by fluids, like liquids and gases, which contain atoms or molecules moving freely. As these particles move, they bounce into each other and push out, creating pressure.
This pressure can be calculated by dividing the force of the pressure by the area it's pressing on. The standard unit used to measure pressure is called the pascal.
What Is Acceleration?
Acceleration is the rate of change in an object's speed and direction over time. An object's acceleration depends on its mass and the strength of the force acting on that mass. Objects with heavier mass require more force to accelerate.
For this reason, objects with different mass still fall at the same speed. The heavier objects experience a greater pull from gravity, but they're harder to accelerate because of their heavier mass. This extra mass perfectly balances out the additional gravitational force.
How Acceleration Works
Because of gravity, falling objects accelerate toward earth at 9.8 meters per second. This rule can be tweaked when air resistance is exploited to slow an object's fall, like it is with parachutes.
What Is Matter?
Matter is anything that has mass and occupies space. Because matter occupies space, other matter can't be in that same space. The amount of space which matter takes up is known as its "volume."
Mass is the amount of matter in any object. Or, as I like to think about it, the amount of matter in any doodad. The mass of a doodad is the same regardless of where it is and where it goes in the universe.
Mass vs. Weight
Although many people use the word "weight" and "mass" to mean the same thing, for scientists like us, weight is different than mass. Weight is a measure of the force of gravity exerted on a doodad. The force of gravity is what keeps doodads from floating off earth and into outer space.
The strength of the force of gravity on a doodad depends in part on the doodad's mass. If a doodad has more mass, gravity's force is stronger, so the doodad has more weight.
What Is Science?
In studying these fields, science seeks solely to describe "how" the phenomena operate. Science avoids the question of "why," which is considered an issue best left to philosophers. For example, science attempts to explain how the universe formed and how gravity functions, but intentionally avoids the questions of why the universe formed and why gravity functions.