We learned about physical and chemical changes in Coiscéim this week.
We learned that everything is made of ‘stuff’ and scientists call this stuff matter.
We learned that in a physical change the matter in an object stays the same but in a chemical change the matter changes. Chopping wood is an example of a physical change while burning wood is a chemical change.
We also learned the 5 signs of a chemical change;
- temperature change
- colour change
- gas created
- Something new is formed
For our first experiment we mixed bicarbonate of soda with vinegar.
We poured 100ml of vinegar into a cup and 3 teaspoons of bicarbonate of soda in a rubber glove.
Next we tipped the soda into the vinegar. The glove began to fill with a gas. We decided it was a chemical change.
There was so much gas the gloves popped off the cup!
For our next experiment we made some elephant’s toothpaste!
The materials used were:
- 100ml hydrogen peroxide
- Food colouring
- A squirt of washing up liquid
- A tablespoon of dried yeast
- three tablespoons of warm water
- We mixed the hydrogen peroxide, food colouring and washing-up liquid in a bottle
- We mixed the yeast and warm water in a cup.
- We added the yeast mixture to the bottle and took a step back to see the reaction!
We observed a temperature change, gas and the formation of a new substance. We decided it was a chemical change.
For our final experiment we mixed Mentos with diet coke. While there was quite a reaction we decided there wasn’t a chemical change as there was no colour change, no smell, no change in temperature, nothing new was made and the gas was already in the diet coke. We’ll have to do some further research to find out what happened!