Question

ed is washing dishes after cooking his dinner. he notices that some of the dishes still feel oily after being washed. he wonders what factors affect how clean dishes are after they are washed. he has the following supplies available: a sponge, liquid dish detergent, a bar of soap, hot water, cold water, a pile of dirty dishes. using only these supplies, which two questions can ed investigate with an experiment? are dishes washed in a dishwasher cleaner than dishes washed by hand? are dishes cleaner when washed with liquid dish detergent and hot water or with liquid dish detergent and cold water? are dishes cleaner when washed with liquid dish detergent or with a bar of soap? are dishes cleaner when washed with a soapy sponge or with a soapy rag?

Explanation:

Ed has liquid dish detergent, a bar of soap, hot water, cold water among his supplies. He can test the effect of different cleaning agents (liquid dish - detergent vs bar of soap) and different water temperatures (hot water vs cold water) on dish - cleaning. He doesn't have a dishwasher or a soapy rag to test the other two questions.

Answer:

1. Are dishes cleaner when washed with liquid dish detergent and hot water or with liquid dish detergent and cold water?
2. Are dishes cleaner when washed with liquid dish detergent or with a bar of soap?