Archimedes' Principle states:
" a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid"
In other words, when we place a body in a fluid, like water, the volume of the object equals the volume of displaced water.
The simplest example is a bath. If we fill the tub with water up to the top and we lay down inside it, the water will exit, and your bathroom will be a very wet place similar to a lake. The amount of water that came out equals your body volume. You can, with some time and work, calibrate the tub to find out your body volume, 1L=1dm3.
In this example 1+1=2, but sometimes 1+1= "not sure"
What we need :
- glass container,
- tape, one you can write on
- glass container with a scale,
- paper towel,
- hot water.
- Clean the container;
- Apply a vertical strip of tape in the container;
- Fill the scaled container with hot water (container A);
- Pour the water in the other container (container B);
- Use the pen on the tape to mark the water level in container B;
- Fill the container A again and add the water to the container B
- Use the pen again and mark the water level in container B;
- Reject the water;
- With the paper towel clean and dry container B;
- Repeat step 3, 4 and 5;
- Now fill up the container A with sugar;
- Add the sugar to container B;
- Use the spoon to mix the solution;
- Use the pen to mark the level;
1 volume of hot water + 1 volume of sugar it's different from 2 volumes of hot water.
Water molecules are organized like a net. This net is stable and cohesive due to hydrogen bridges. When this net is formed some hydrogen atoms link to neighbor water molecules by a "false" bond with the oxygen, those are called hydrogen bridges. When this happens some "blank spaces" are left between the molecules- in the net. This spaces are as big as the molecules are excited, thats why we used hot water- more empty space makes dissolution more efficient.
When we add the sugar the sugar molecules occupy the empty spaces between water molecules, thats why:
1 sugar unit+ 1 water unit doesn't equal 2 water units
This is a demonstration, but you can make it an experiment:
Try with 1 unit of water+ 1 unit of sugar. Does that equals 2 units of sugar?
Try with cold and ice water, what happens?
Now you can teach some stuff to your math teacher