If you build a campfire, you start with a large stack of sticks and logs. As the fire burns, the stack slowly shrinks. By the end of the evening, all that is left is a small pile of ashes. What happened to the matter that you started with? Was it destroyed by the flames? It may seem that way. What do you think happened? The truth is that the same amount of matter still exists. The wood changed not only to ashes, but also to carbon dioxide, water vapor, and other gases. The gases floated off into the air, leaving behind just the ashes. Although matter was changed, it was not created or destroyed. Because the same amount of matter still exists, we can say that matter is conserved. You may wonder how it can be conserved if something is now missing? Assume you had measured the mass of the wood before you burned it. Assume you had also trapped the gases released by the burning wood and measured their mass and the mass of the ashes. What would you find? The ashes and gases combined have the same mass as the wood you started with. This example illustrates the law of conservation of mass.

Ashes and gases in an example of what?

Jack and Mackenzie wanted to do something fun during their day off from school. They knew that the library had story time on Monday, Tuesday, and Wednesday. Their mother told them they could go to the library every Tuesday for their story time. They packed up the car and drove to the library, ready for a fun morning. When they arrived to the story room, there were lots of other children their age, all sitting cross-legged and ready for the story of the day. The teacher told them they would be reading "The Wild Horse". She began to tell the story of Majestic, the wild horse who could not be calmed. His people had tried and tried to break him, but he was wild at heart. Every time they took him to the river to drink, he would run straight into the water and get soaking wet! He would splash and play until he was ready to go back home, where he would sleep for hours, having worn himself out playing.

In the story about Majestic, every time they took him to the river to drink water, what would he do?

Relying on an animal to come by is risky. A flower may have to wait a long time for the right animals to come by. What if one never passes close enough to the flower? Hoping the wind will blow is also risky for a plant. What if the wind does not blow? What if the blowing pollen does not land on another flower? The wind could even blow the pollen over the ocean where it is wasted. Giving free nectar is costly. It is not a good use of the plants energy. A plant uses a lot of energy to produce nectar. Some animals may just drink the nectar. They may not carry off any pollen in return. To improve their chances, plants evolved special traits. For example, they developed ways to hide their nectar. Only certain animals were able to get at the plants hidden nectar. These specific animals might be more likely to visit only flowers of the same species. This was also a benefit for some animals. Animals also evolved special traits to get to the nectar.
How do plants protect nectar?