One simple inquiry based lesson I’ve done in the past is to show that water rises when ice melts. I know that this isn’t easy as many schools might not have a freezer but my old school was fortunate to have one.
Materials needed: Ice, water, container, marker.
Pour water into a glass and add ice. Use a marker to show where the water level.
Discuss with the children what they think will happen. Ask the children to predict what will happen/how far they think that the water will rise. Just wait and see how far the water rises as the ice melts.
Extensions:
Ask the children why ice floats?
Put water in different size containers and add ice? Why does the water levels rise more in a thinner shape glass than in a wider shaped glass?
Time how long it takes for the ice to melt. Does it melt quicker/slower in different conditions? What are these conditions?