In Year 6 we have been researching the human heart. We found out that there are 4 chambers: the right atrium, the left atrium, the right ventricle and the left ventricle. When you breathe in oxygen, it travels to your lungs, then blue blood ( blood without oxygen) collects all the oxygen and turns to red blood ( blood with oxygen). This blood then travels toevery part of your body from the top of your hy and to the tip of your toes. Next it collects all the carbon dioxide and travels back up to your lungs  and then you exhale. All this happens in a matter of seconds (every time your heart beats).