Why two ingredients are necessary in order for a substance to be called a hand cream

lanolin  and a mixture of stearic acid and triethanolamine

Explanation:

lanolin -

It is responsible for the absorption of the water in the skin , i.e. , to make the skin hydrated .

Lanolin is ester of the long chain fatty acid , with waxy feel to it .

The mixture of stearic acid and triethanolamine  act as a emulsifying agent .

These reactants reacts to give salt , hence act as an emulsifying agent .  

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.