Please explain why steel is denser than wood.
Steel is basically a mixture (not the compound) of iron and carbon. Iron, by itself is an element and so is carbon. The atoms of Iron are larger in size compared to carbon. All the atoms of all the elements, smaller or larger, are spherical. If naturally a solid, the atoms of all such elements have voids as their atoms are closely packed. You can imagine a basket of oranges; you could see that void or empty space (which I am speaking about) between four or more of the oranges put together. Now, when heated to more than about 1500 degrees celcius, Iron melts and atoms in molten form increase space between themselves. Raising the teperature to 1800 degree celcius, carbon is mixed with iron. At this stage it causes the spherical carbon atoms to fill in the spaces present amongst the spherical atoms of the iron. On cooling, already dense iron becomes denser because no space is left there between its atoms. This denser form of iron + carbon has become steel in which carbon is not more than 3 to 4% of the total volume. Wood is nothing but a fallen and dried tree's part. When green and alive, tree's stem and branches have pores in there texture, which are fillled with water and other biological fluids necessary for the life of the plant. When dried all the fluids, especially water gets evaporated. and the pore are empty now. The term Density, means mass divided by volume (kg / cubic meters). Iron + Carbon (the steel) so tightly packed and Iron having very high atomic weight is surely denser than wood with just carbon and a few other elements with no significant role to play in the mass calculation; particularly if their are empty pore spaces filled with air only. Imagine the mass (which common people mistakingly call the weight) in kilograms of a peice of steel with dimensions of 1 meter cube and imagine the same for the dried wood. What do you think---which one is denser?
Steel is made up mostly of iron with a very small amount of carbon added. Iron is a metallic element with a high atomic number which means it's molecules contain lots of particles and consequently it is relatively heavy, or dense. Wood on the other hand is made up mostly of carbon which is a non-metallic element with a lower atomic number and fewer particles in each molecule, and consequently it is a lot lighter or less dense than steel.
A steel atom has more mass than wood becaue it has a larger number of protons and neutrons in it's nucleus. So steel packs more mass (more matter) into the same space as wood. Density is mass/volume. If you have a 1 cm cube of steel and a 1 cm cube of wood they are the same volume (1 cubic cm) but the steel has more matter in that volume and therefore is denser.
The atoms in steel are more tightly packed. They have a greater mass in a smaller volume than wood. Basically, if you take 100 g of steel and 100 g of wood, the piece of steel will be smaller (less volume) than wood and therefore more dense. Density = Mass/Volume
