UNIT 7: MATTER
PHYSICAL CHANGES
There are four important types:
MIXTURE:
Two or more substances are
mixed together.
e.g. a salad, coffee with milk, water with sugar
EXPERIMENT 1: you have two glasses with water. In one you put salt and move it. Taste them. Are they similar?
Now, wait until the water evaporates from the two glasses. What happened?
CHANGE OF SHAPE:
We apply a force to an object and it changes it shape or it breaks
e.g. you stretch a rubber band and it breaks, you press plasticine and it changes its shape
CHANGE OF SIZE:
- Expansion: the temperature goes up (hot) and it gets bigger
-Contraction: the temperature goes down (cold) and it gets smaller
EXPERIMENT 2: take a piece of plasticine, a paper, a rubber band, a can, a bottle of water,slime... You can try with a lot of things. Now apply force. What happens in the different cases?
EXPERIMENT 3: you have two bowls, one with hot water and another one with cold water. You take an empty bottle of water (without the cap) and put a balloon on the top of it. Then put the bottle in each bowl. What happens?
Click on the video to see how to do it.
CHANGE OF STATE:
-Melting > solid to liquid
-Evaporation> liquid to gas
-Solidification > liquid to solid
-Condensation > gas to liquid
EXPERIMENT 4: take an icebucket and put some water in it. Place it in the freezer and wait. What happens? What process is it? Now take the ice cube and place it in a pan with hot. What happens? What is the name for this process? Wait more time and write what happened