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Simulations from PhET Interactive Simulations
University of Colorado Boulder http://phet.colorado.edu
Game about moments (the lever law) Simple moment simulation
Forces and motion Simulation about the Lever Law
Springs and Hookes Law Learn about Hookes Law
How friction heats up a surface (Kinetic theory simulation)
Density Learn about density by seeing what floats
Energy Change Kinetic, potential and intenal energy change
pH scale Test the pH of different substances
Colour mixing See what happen when different colours are mixed together
Balancing chemical formula (GCSE)
Puzzles
The magic triangle
A triangle can be made by arranging 4 shapes on a 5 x 13 grid.
By re-arranging the shapes a new triangle can be made.
The pieces in the lower triangle are exactly the same as those in the upper triangle, but now seem to take up less space so there is one blank square
Where does the white square come from?
Hover your mouse here for the solutionHere is another similar puzzle:
4 similar qudrilateral shapes are arranged into a square.
If each is rotated by 180º they make a similar square but there is a piece missing in the middle.
Where does the extra space come from?
Bear Puzzle
A bear walks 1 kilometre south, 1 kilometre west and then 1 kilometre north
He ends up in exactly the same place he started.
What colour is the bear?
4 litres of water problem
You are camping by the edge of a stream and a recipe calls for EXACTLY 4 litres of water.
Unfortunately, you only have two empty containers, one that holds 3 litres of water and one that holds 5 litres.
How can you get exactly 4 litres (you can fill and empty the containers as many times as you like using water from the stream).
Hover your mouse here for the solution