Chemistry

Over the last couple of weeks I have attended two chemistry workshops. During the first workshop we made a thick sticky substance called casein. It smelt disgusting and it looked all lumpy and gross as well. See down below for the recipe for casein. Casein is an edible thickener but it tastes horrible! You can use casein to make plastic objects such as buttons. Some people made a long flat oval mold of casein on the lid of a yoghurt container. My groupmade a ball of casein. Our hypothesis was that the ball would be rubbery plastic so it would bounce. When we had shaped the ball we wrapped it in gladwrap and left it for a week. Next week we had a look at it. It was still soft and spongy, so we took it out of the gladwrap and left it for a week. Thenext week we found it was too hard. I was given the ball so I tore off the hard layer and found asoft layer underneath. I tried bouncing it but it didn't work.

The second week we tested household products that you would find in the kitchen to see if they were a base, a neutral or an acid. We each had a small cup of purple cabbage water. When we had chosen a product each we put some into our cabbage water. If it was a base the water would turn blue. If it was a neutral the water woud stay the same and if it was an acid the water would turn pink. I had a lemon. It was very acidy and the water turned a pink colour instantly. Quite a few products didn't make the water turn any colour like the coffee it made the water turn brown. After everyone had tested their product we were given a piece of litmus paper. Thepaper also turned red if acidic, blue if it was a base and green if it was a neutral. My lemon wasthree colours away from being one of the most acidic things in the world. This was the highest rank in colour that all the products got up to. Three other products were as acidic as a lemon- lime was amongst them.

Here is a picture of the purple cabbage water, acidic purple cabbage water, netural purple cabbage water, and base purple cabbage water, the litmus beginning to turn red in the presence of a lemon and the many colours that litmus paper can turn.