Who has never cried while cutting an onion? (well, apart from those who have never cut one hehehe). This is a little explanation in easy terms.
Inside the onion cells there are some chemical compounds that containsulfur. When you cut an onion its cells are broken and those chemical compounds then undergo a reaction that transforms them into a more volatile sulfured products, which are released into the air.
These sulfured compounds react with the moisture in your eyes forming sulfuric acid, which produces a burning sensation. The nerve endings in your eyes are very sensitive and so they pick up on this irritation. The brain reacts by telling your tear ducts to produce more water, to dilute the irritating acid. So you cry to keep your eyes protected from the acid.
There are some tricks to make onion-dicing less problematic:
- Chop the onion under cold water. The volatile sulfured compounds will be released but then they react with the water, instead of reaching your eyes.
- You can freeze the onion for 10 minutes before cutting it. The cold temperature of the onion will slow down the chemical reaction which forms the volatile sulfured compunds.
Inside the onion cells there are some chemical compounds that containsulfur. When you cut an onion its cells are broken and those chemical compounds then undergo a reaction that transforms them into a more volatile sulfured products, which are released into the air.
These sulfured compounds react with the moisture in your eyes forming sulfuric acid, which produces a burning sensation. The nerve endings in your eyes are very sensitive and so they pick up on this irritation. The brain reacts by telling your tear ducts to produce more water, to dilute the irritating acid. So you cry to keep your eyes protected from the acid.
There are some tricks to make onion-dicing less problematic:
- Chop the onion under cold water. The volatile sulfured compounds will be released but then they react with the water, instead of reaching your eyes.
- You can freeze the onion for 10 minutes before cutting it. The cold temperature of the onion will slow down the chemical reaction which forms the volatile sulfured compunds.
How to make invisible ink at home?
This is a funny experiment to do with kids at home.
You can play with your kids at home making invisible ink with basic products that you have in the kitchen. There are many methods to make invisible ink. These are some of the easiest ones:1) Lemon juice method
- Ingredients: just lemon juice.
Write your message on a piece of paper with a brush or tootpick embedded in lemon juice. Let it dry completely.
To read the message heat the paper for a while (for instance hold it close to a light bulb) until the words become visible. Warning: do not hold paper too close to the heat and be careful not to let it get too hot!
- Chemical explanation: Lemon juice is a mild acid that weakens the paper upon contact. So when you heat the paper the part with the juice burns before the rest making your message visible.
2) Baking soda method
- Ingredients: baking soda and water in same amount (for instance 30 mL of each).
Mix them and use a toothpick or brush to write on a piece of paper. Wait until it dries completely.
To read the message paint the paper with a brush or a sponge embedded in concentrated grape juice. The message should show up.
- Chemical explanation: You've made an acid-base reaction. The baking soda is a basic compound that reacts with the acid contained in the apple juice, forming a new compound that has a different colour, making your message become visible.
No comments:
Post a Comment