Density is also an important physical property of matter. The concept of density combines what we know about an objects mass and volume. Density reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter is more dense. Differences in density of matter explain many phenomena. It explains why helium balloons rise. It explains why currents such as the Gulf Stream flow through the oceans. It explains why some things float in or sink. You can see this in action by pouring vegetable oil into water. You can see a colorful demonstration in this video.

What are some things density explains?

Ratners Group PLC, a fast-growing, acquisition-minded London-based jeweler, raised its price for Seattle-based specialty jeweler Weisfield's Inc. to $57.50 a share, or $62.1 million, from $50 a share, or $55 million, after another concern said it would be prepared to outbid Ratners's initial offer. The other concern wasn't identified. Ratners's chairman, Gerald Ratner, said the deal remains of "substantial benefit to Ratners." In London at mid-afternoon yesterday, Ratners's shares were up 2 pence (1.26 cents), at 260 pence ($1.64). The sweetened offer has acceptances from more than 50% of Weisfield's shareholders, and it is scheduled for completion by Dec. 10. The acquisition of 87-store Weisfield's raises Ratners's U.S. presence to 450 stores. About 30% of Ratners's profit already is derived from the U.S.

What percentage of Weisfield's shareholders has accepted the sweet offer?

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?