This lesson is the first in a three-part series that addresses a concept that is central to the understanding of the water cycle—that water is able to take many forms but is still water. This series of lessons is designed to prepare students to understand that most substances may exist as solids, liquids, or gases depending on the temperature, pressure, and nature of that substance. This knowledge is critical to understanding that water in our world is constantly cycling as a solid, liquid, or gas.
In these lessons, students will observe, measure, and describe water as it changes state. It is important to note that students at this level "...should become familiar with the freezing of water and melting of ice (with no change in weight), the disappearance of wetness into the air, and the appearance of water on cold surfaces. Evaporation and condensation will mean nothing different from disappearance and appearance, perhaps for several years, until students begin to understand that the evaporated water is still present in the form of invisibly small molecules." (Benchmarks for Science Literacy<span>, </span>pp. 66-67.)
In this lesson, students explore how water can change from a solid to a liquid and then back again.
<span>In </span>Water 2: Disappearing Water, students will focus on the concept that water can go back and forth from one form to another and the amount of water will remain the same.
Water 3: Melting and Freezing<span> allows students to investigate what happens to the amount of different substances as they change from a solid to a liquid or a liquid to a solid.</span>
If ice is warmed and becomes a liquid, the process is endothermic.
The process requires heat in order to proceed. If ice stays in a very cold place, it will not melt unless it's heated. If ice is placed outside where it melts on its own, it gets the heat from the surroundings.
Atomic mass number is the number of protons and neutrons. Subtract 80-35=45 is the number of protons. Because the atom is neutrally charged, the number of protons must equal the number of electrons, so there are 45 electrons.
<em>Answer:</em>
- The atom have a full valence electron shell.
<em>Explanation:</em>
- My question is that why covalent bonds take place?
Every atoms tends to from bond with another atoms in order to get nearest electronic configuration of nobel gases. They become stable when their valence shell become complete. So when covelant bond forms between atoms, share electrons to each other and stabilize themselves.
Answer:
1mpm(1 meters per minute) Explanation: Speed:Distance/time 25/25=1 plz mark as brainliest
