Tracking Physical and Chemical Change
Materials:
- 1 cup
- 1 medicine measuring cup
- Salt
- Water
- 2‐3 tablets of differently colored medicine or vitamin pills
- 1 long match
- 1 matchbox
Instructions:
1. Take your cup and fill it with water.
2. Fill your medicine cup with 30mL of salt and put it into the water. Dissolve the salt by stirring the water.
3. Put your cup in a sunny place and wait several days. What happened to the salt and water?
4. Put the differently colored medicine and vitamin pills on a small plate and leave them out in the open and underneath light. After several hours, what has happened to the tablets? After two days, what changes do you see?
5. Ask an adult to help you for this next one: Ask the adult to light a match by striking it along the sides of a matchbox. What do you notice about the lit match? Place a finger close the flame, what do you feel? What does the match look like when the fire goes out?
The three activities demonstrate physical and chemical change. When you dissolve salt and water, the salt seems to mix in perfectly with the water. However, it is still salt. You will see that once the water evaporates, the salt will remain in the cup. The medicine pills will change color when you leave it out in the open because the pills react to the oxygen in the air and the light. The reason why pills are stored in colored sealed bottles is to prevent this chemical change from happening. Finally, the lighting of the match is another demonstration of chemical change. Heat is emitted from the flame and when the fire burns out, the wood that the match was made of has changed in color and consistency.
Next Article: Methods of Heat Transfer
