Density- how much matter is packed into a specific volume. Do you think a mini-marshmallow is very dense? Will it float in your hot chocolate? What about a cube of sugar that's about the same size as a mini-marshmallow? Sink or float?
Does it matter if you have a bigger marshmallow?
What happens if you smush all the air out of the marshmallow?
There would be the same number of atoms, but in a smaller amount of volume (amount of space), so it would be much more dense. Now would it sink or float?
Go try it out!
Ever heard of the phlogiston theory? No?! Well, if you've never heard of it, it's safe to say that it's one theory that's been disproven.This theory stated that fire, or combustion, was made up of an element called phlogiston. Scientists thought that when things burned they released phlogiston into the air. During the late 18th Century, Antoine Lavoisier disproved the phlogiston theory. He is one of the founders of modern chemistry. He was quite wealthy, and this allowed him to obtain some of the best equipment available at the time, and allowed him spend his time conducting experiments (check out the pic). He eventually demonstrated that there was an element, which he named oxygen, that played a major role when substances burned. After hundreds of experiments and very careful measurement he showed that the mass of products in a reaction are equal to the mass of the reactants. In other words, no mass is lost in a chemical reaction. This became known as the Law of Conservation of Mass. We attempted to prove this law with our Alka-Seltzer experiment!
We're well on our way in our Physical Science unit. We've explored the Periodic Table of Elements, atoms, molecules and physical and chemical changes. Looking forward we're going to investigate properties of matter such as: boiling points, melting points and density. We're also going to learn about conservation of mass! Wow! Sounds like a lot, but we'll get through it.
I've got a couple Zaptions for you on Atoms and Molecules and another one one Physical and Chemical changes. Check the Zaption page for the links!
