WALA: Where does water come from?

WALA: Where does water come from?

L.O:   to know that air contains water vapour and when this meets a cold surface it may 

condense.

AIM: I am investigating where water come from to form outside a cold glass.

Equipments

1. two glasses

2. ice

3. water

4. measuring jug

5. a cloth

My prediction: .............................................................................................................

Reasons for my prediction: .........................................................................................

METHOD

1. Wipe both glasses with a dry cloth.

2. put water on one glass and ice cubes on the other glass. leave the glasses of 10 min and then observe them.

Drawing of the investigation

Learners to draw in their notebooks. ( check the next slide to have an idea of how your drawing will look like.)

Results

1. Were either of the glasses wet on the outside at the start of the investigation? How did you make sure of this?

2. a) Were either of the glasses wet on the outside at the end of the investigation? If so, which glasses?

b). Where did the water come from and why?

3. Condensation is the reverse of evaporation. Explain why this is so.

Conclusion

1. No. I wiped the outside of the glasses with a 

cloth.

2 a). Yes. The glass that contained the ice was wet on the outside.

b). The water came from water vapour in the air that condensed on the outside of the cold glass.

3. In condensation, a gas changes into a liquid. In evaporation, the opposite happens and a liquid changes into a gas.