Archives of Ask A Scientist!
About "Ask A Scientist!"
On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.
Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.
In your experiment, you are separating casein from milk. Casein is found naturally in cow's milk: however, the amount of casein in a typical glass of milk would only fill a couple of thimbles! To get this sticky stuff away from the rest of the milk, which isn't very sticky, you add vinegar. Vinegar contains an acid, and it causes the casein to precipitate (in other words, it turns the casein into a solid). Now, the casein can be easily separated from the rest of the milk, which is a liquid. The problem now is that casein isn't very sticky after being reacted with acid. Plus, these curds are kind of like cottage cheese - you wouldn't want to stick paper together with this, would you? (yuck!). To make it into a glue, you must add a base. A base is the chemical opposite of an acid. In your experiment, the base is sodium bicarbonate (commonly known as 'baking soda'). When you add it to the curds, it reacts to make the casein soluble again (no longer chunky!), and it is now sticky like a glue.
- I know that a TV screen is made up of lots of blue, green and red dots, so why does the light coming out of it look blue from a distance?
- How does energy that is released as heat get reused?
- How can information be sent on radio waves, etc? How can things that have no mass contain messages?
- What is ceramic made of?
- If hydrogen and oxygen are both flammable why doesn't water burn?
- If solids, like glass and ice, are made of tightly packed molecules, how can we see through them?
- Why is a mirror left-right reversed, and not up-down backwards?
- Why is there discussion as to whether or not glass is a liquid or a solid?
- What is the volume of water in a gallon of ice?
- When is dry ice a fluid?