And for those wanting to know more, the reason the left ventricle is bigger and beats harder is because of the path blood takes through your body. It gets pumped out of your left ventricle to supply all the cells in your body with oxygen and nutrients, then it returns to the heart and gets pumped out of your right ventricle to the lungs where it resupplies its oxygen and gets rid of carbon dioxide, then returns back to the heart to get pumped out of the left ventricle again. So the right side has a much shorter route it has to send the blood through and therefore doesn't need to be as big.

We're getting into things not relevant to the original question now, but a fun fact is that while many people think what defines an artery and a vein is whether it carries oxygenated or de-oxygenated blood, this is actually not true. The left ventricle does pump blood through arteries to the rest of your body and then that blood returns back to the heart through veins, but the right ventricle pumps de-oxygenated blood through the pulmonary artery to the lungs, and then the oxygenated blood returns to the heart through the pulmonary vein. So it's actually the direction of the flow relative to the heart that defines veins and arteries, not the oxygenated state of the blood it carries.