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Basic primer on Newton's First Law of motion.

Newton's Laws of Motion

Newton's second law of motion is F = ma, or force is equal to mass times acceleration. Learn how to use the formula to calculate acceleration.

Learn about Newton's third law of motion, which states that for every action there is an equal and opposite reaction. Look at multiple examples that illustrate this law, including pushing a block on ice, pushing against a desk, walking on sand, how rockets work, and how an astronaut could save themselves from drifting in space.

Overview of animal and plant cells. Topics include cell walls, vacuoles, chloroplasts, peroxisomes, lysosomes, mitochondria, etc.

Even though molecules, proteins, viruses, and cells are all tiny, there are significant size differences between them. The diameter of a water molecule is roughly 0.28 nanometers. The diameter of the protein hemoglobin is roughly 5 nanometers. The diameter of the HIV virus is roughly 120 nanometers. A red blood cell is 6-8 micrometers.