Unit 2 Reflection

       This unit was about the nature of matter, compounds, molecules, bonds, acids, bases, and pH. In response to the essential unit question, I believe that increasing molecular complexity serves as the building blocks for life by learning from the ground-up, starting with atoms, the basic unit of matter, and working your way up to compounds and molecules or the types of bonds. By learning these things in order, it gives us a better understanding of what we're really learning by starting small, instead of diving in head first.
        About the nature of matter, I learned that atoms are the basic unit of matter and make up everything we see and feel in this entire world, including all of us. Atoms are made up of three particles; protons, neutrons, and electrons. Protons have a positive charge and have the same mass as neutrons, neutrons have no charge/neutral charge, and electrons are negatively charged, and are 1/1840 size of a proton while always in constant motion. The nucleus is in the center of an atom, made up of protons and neutrons. I had no trouble remembering the charges of each of the particles, though I occasionally have trouble remembering what the nucleus is and what it's purpose is. Atoms are also the basic unit of elements, which are pure substances that are listed on the Periodic Table with their atomic number. The atomic number of an element never changes.
     I also learned that compounds and molecules are formed by two or more elements and have formulas, which are abbreviations of the number and types of atoms in a molecule (Ex: H20 = 2 hydrogens + 1 oxygen). I have trouble memorizing the different types of bonds, so I realize I have to work on that. Chemical bonds are the energy stored between atoms. There are three types of bonds; Ionic bonds, Covalent bonds, and Hydrogen bonds. Ionic bonds form when an atom gains or loses an electron, covalent bonds are electrons shared between atoms and could have double or triple bonds, and while hydrogen bonds are not as strong as covalent or ionic bonds, they are able to hold molecules together due to slight attraction of positive to negative charged regions. I had a lot of difficulty memorizing the types of bonds and their purposes, so I'm going to keep working on that.
      We learned why water is wet by first going over the properties of water. One of it's properties, polar is the unequal distribution of charge between H and O. It has the ability to form multiple H-bonds, is the most abundant molecule in most living organisms, is less dense when frozen, and has high specific heat - absorbs a great deal of energy.
     I learned that pH is the measurement of hydrogen ions in solutions. I was also taught about the pH scale, 7=neutral, anything larger than 7 is acidic, and anything less than 7 is basic. I might have trouble remembering the scale, so I'm going to study that some more.

Sweetness Lab

                                                                         Sweetness Lab

     1. I believe that monosaccharides are sweeter than the other forms of carbohydrates, since fructose and glucose are really sweet and are monosaccharides. Disaccharides are neutral, since while sucrose is really sweet, lactose and maltose really aren't. And finally, polysaccharides are the least sweet, since both starch and cellulose are really bland.

2. In crystalline form, most monosaccharides are present in a "long chain" structure. Some monosaccharides are modified by cellular enzymes to enhance or change their cellular function. The number and type of monosaccharides used, as well as the position of bond between them, determines the 3D structure of each carbohydrate.

3. All testers gave each sample the same or near the same rating. One reason why it could taste different for one person is if they have different tastebuds, accidentally mix sugars, or dont drink water between tasting.

4. Our tongues detect the majority of the tastes using protein receptors on the surface of the taste cells. The receptors snap together in specific ways, and when they do, the cells send signals to the brain reporting the molecules' presence. Therefore, the testers could rank sweetness differently because although our brains can recognize the same five tastes-bitter, sweet, salty, sour and savory-the suite of chemicals can trigger those signals vary from one person to the next.

Characteristics of Life

Jean Lab

In this lab, we asked the question "How would it affect the jean fabric squares if we put different amounts of bleach in each of the petri dishes they were in?" We found that 100% bleach affected the jeans the most, and, in order, 50%, 25%, 12.5%, and 0% were not quite as effective as 100% bleach, but still did a lot of damage. 100% bleach drained nearly all of the color in the jeans, their once dark blue navy color now a blue white. 50% bleach took away most of the color but still left it blue. 25% bleach affects the texture of the jeans, but not so much the color. And finally, 12.5% and 0% did little to no damage to the jeans. This lab was important for our learning because it taught us more about the scientific method and gave us a better understanding of it.