Now how do you teach taste distinction to pre-schoolers?

While doing a project of collecting pictures of food of different tastes, I was observing our middle child working with the Expat Daddy, suddenly as if she hit the jackpot she shouted: "Dad, this one! Sour! (showing him a picture of soap). What about paper dad, is it sweet?" -- hahahaha!

Now I am laughing about it, but seriously I am a bit surprised how hard it is for my girls to comprehend taste distinction when it is one topic that they could actually observe and try out. I remember when our Big Ate was also just in pre-school and we were reviewing the topic I asked her what is the taste of sugar and she told me "Masarap! (delicious)" hahahaha! And now our Small Ate could not tell me what chocolate tastes like... she does not agree that it is sweet and says "no mei-mei, may iba pa syang taste!"
Haaay.... I wonder how it would be for our baby Oyen when she finally starts with her science lessons in pre-school...
Sure I am a hands on mom when it comes to my children's education, but on this topic... I am definitely hands off! Let the Expat Daddy take over! Lol!