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Cell theory

Introduction to cell theory--the idea that 1) all living things are made of one or more cells, 2) cells are the basic unit of life and 3) all cells come from other cells. Explore the roles that Hooke, Leeuwenhoek and others played in developing cell theory.

Hooke and Leeuwenhoek were two of the first scientists to use microscopes to study the microscopic world of cells. Hooke coined the term "cell" after observing the tiny compartments in cork, while Leeuwenhoek discovered a variety of living creatures in pond water, blood, and other samples. They contributed to the cell theory by suggesting that cells are the fundamental units of life and structure, and that all living things consist of one or more cells that originate from other cells by division. 

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2015
Schepper/Auteur
Sal Khan
Trefwoord
Cells

Cells and organisms

All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular).

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2022
Schepper/Auteur
Khan Academy
Trefwoord
Cells

Charges and Fields

  • Determine the variables that affect the strength and direction of the electric field for a static arrangement of charges.
  • Investigate the variables that affect the strength of the electrostatic potential (voltage).
  • Explain equipotential lines and compare them to the electric field lines.
  • For an arrangement of static charges, predict the electric field lines. Verify the prediction using vector addition.
Onderwerp en thema
Form 1
Physics
Force
Types of forces
Type bron
Simulatie
Taal
English
Uitgever
pHET Interactive Simulations
Publicatiedatum
No date
Schepper/Auteur
Amy Rouinfar (lead designer - HTML5)
Trefwoord
Electric Field
Voltage
Electrostatics

Coulomb's Law

  • Relate the electrostatic force magnitude to the charges and the distance between them
  • Explain Newton's third law for electrostatic forces
  • Use measurements to determine Coulomb’s constant
  • Determine what makes a force attractive or repulsive
Onderwerp en thema
Form 1
Physics
Force
Types of forces
Type bron
Simulatie
Taal
English
Uitgever
pHET Interactive Simulations
Publicatiedatum
No date
Schepper/Auteur
Michael Barlow (lead developer)
Trefwoord
Coulomb's Law
Electrostatics
Electric Force

Force Diagrams

A force diagram is a useful tool to help us visualise forces acting on an object and gives us informa- tion about the object’s motion. We often use force diagrams when solving calculations involving the forces acting on an object.

Onderwerp en thema
Form 1
Physics
Force
Types of forces
Type bron
Werkbladen en klassikale activiteiten
Taal
English
Uitgever
Department of Higher Education
Publicatiedatum
No date
Schepper/Auteur
Linda Pretorius
Deelnemer
Michael Atkinson
Trefwoord
Force
External Force
Net Force

Forces and Motion

  • Predict, qualitatively, how an external force will affect the speed and direction of an object's motion.
  • Explain the effects with the help of a free body diagram.
  • Use free body diagrams to draw position, velocity, acceleration and force graphs and vice versa.
  • Explain how the graphs relate to one another.
  • Given a scenario or a graph, sketch all four graphs.
Onderwerp en thema
Form 1
Physics
Force
Types of forces
Type bron
Simulatie
Taal
English
Uitgever
pHET Interactive Simulations
Publicatiedatum
No date
Schepper/Auteur
Noah Podolefsky (Lead)
Trefwoord
Force
Velocity
Acceleration

Forces and Motion: Basics

  • Identify when forces are balanced vs unbalanced.
  • Determine the sum of forces (net force) on an object with more than one force on it.
  • Predict the motion of an object with zero net force.
  • Predict the direction of motion given a combination of forces.
Onderwerp en thema
Form 2
Physics
Motion in a straight line
Distance and displacement
Type bron
Simulatie
Taal
English
Uitgever
pHET Interactive Simulations
Publicatiedatum
No date
Schepper/Auteur
Noah Podolefsky (Lead)
Trefwoord
Force
Motion
Friction
Speed

Impact velocity from given height

Determining how fast something will be traveling upon impact when it is released from a given height. 

Onderwerp en thema
Form 2
Physics
Motion in a straight line
Distance and displacement
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2011
Schepper/Auteur
Sal Khan
Trefwoord
Initial Velocity
One dimensional motion

Introduction to the cell

Introduction to the cell.

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2017
Schepper/Auteur
Sal Khan
Trefwoord
Cells

Motion in Two Dimensions

In this chapter, we’ll use vectors to expand our understanding of forces and motion into two dimensions. Most real-world physics problems (such as with the game of pool pictured here) are, after all, either two- or three-dimensional problems and physics is most useful when applied to real physical scenarios. We start by learning the practical skills of graphically adding and subtracting vectors (by using drawings) and analytically (with math). Once we’re able to work with two-dimensional vectors, we apply these skills to problems of projectile motion, inclined planes, and harmonic motion.

Onderwerp en thema
Form 2
Physics
Motion in a straight line
Distance and displacement
Type bron
Studieboeken
Taal
English
Uitgever
openstax
Publicatiedatum
2020
Schepper/Auteur
Openstax
Trefwoord
Resultant
Resultant vector
Tail
Graphical method