Germination is the process a dormant seed undergoes as it begins to sprout. The seed needs the right mix of oxygen, water and light to begin germination. Once the conditions are right, the seed begins to absorb oxygen and water and expand and take up more room in the container. Eventually a root and a shoot containing the stem will emerge.
As they germinate, seeds take in oxygen and release carbon dioxide through the process of cellular respiration. During cellular respiration, the bean or seed breaks down sugars that mix with oxygen to produce carbon dioxide, water and energy. Cellular respiration is what allows the bean to start growing and expanding. The byproducts cause pressure to build in the container holding the pinto beans.
You will need an empty container with a lid, enough sand to almost entirely fill the container, water and pinto beans. You should have enough water that you can fill the container once you've added the sand and the beans. You can also choose to include another kind of bean, such as a kidney bean.
Pour the sand into the plastic container until the container is almost full. Leave a small space at the top for your beans. Add the beans until they reach the top of the container. Slowly add the water, making sure that it flows in between all the cracks and air pockets between the beans and the sand. Put the light on and let the container sit for several days until the beans start sprouting.