November 2017 archive

Archimedes Challenge

The Archimedes Screw

The Archimedes Screw which can also be known as the screw pump was invented back in about 287 to 212 B.C (that’s the time Archimedes was alive). It was created by a now famous inventor Archimedes, renowned for his early inventions and principles of his day. Although Greek born Archimedes was raised in the ancient city of Syracuse, now modern day Sicily. When Archimedes was still a young boy he would travel to Egypt, to study in Alexandria, the land once commonly known for its other famous inventor Euclid, but not for very long. Archimedes would learn his passion for inventing while in Egypt and would pursue it when he got back home. Archimedes would flourish in this career making ground breaking inventions of his time, some can even still be seen in modern day. For one of his most coveted inventions to be built it would be an problem that simply needed solving and Archimedes would deliver. The king (Hiero) would ask for assistance with getting the rainwater out of the hull of his ship, that’s when he came up with the idea for the screw. Although the screw didn’t really have any short term implications, it actually improved the lives of many of that time, in the future it can be linked to the cause a ripple effect on those involved. Archimedes first “big” invention was this, and being successful in this led him to create bigger things such as the mirror of death (which would wreak havoc along many foreign ships too come) creating this mass weapon would put an even bigger target on his hometown Syracuse, and eventually it would be raided by the Roman army. Not only did many in his town get killed but so did he, when a soldier saw him carrying mathematical books that looked of importance he killed him then and there. Now it can be seen being used it multiple different ways, mainly for things like sewage and irrigation/drainage purposes, but of course with some modern day improvements.

The Archimedes screw has been used for a long time, with that came many improvements (things like a motor instead of a manual lever, and metal instead of wood). To be explained simply it’s just a big screw inside of a tube, that moves liquid up it, it’s really just an alternative to a bucket pulley system. Its design allowed for any excess product that would fall back down when being used to not go to waste you would eventually be able to get up all the liquid that was there before making it quite efficient, the manual labour was drastically decreased when compared to the efforts of a pulley system. For the concept to work it has to be held at about a 45 degree angle otherwise the liquid would travel down the spiral and not up it (think water slide) because there would be no pockets for the water to stay while spinning up the tube. The reason the liquid travels in these “pockets” up the tube is because gravity always wants to force it into the next dip (bottom of spiral) and so on until it reaches the top of the screw where it will then be dispensed. The physics behind it has to do with the basic laws of gravity and motion, it’s pretty basic the only numbers that really play a major factor how it works is the angle you hold it at, which can be determined once its already built. However when building it you have to take into the account of the size of you spiral it has to fit perfectly into your tube otherwise it might not work you will have to do some measurements and figure out the circumference of the circle (πr^2) to see the radius that you would need for your spiral discs. It can also be related to the potential energy as it spins around the tube it builds up and then it is released as kinetic energy at the top of your tube, they force/work needed is also effected by the coefficient of friction (what materials you used) for example super smooth woods gliding against each other would be easier to spin then a rough plastic scraping along the sides of the tube (like our example).

The lever allowed for less work input from human sources (made it more efficient). The tube is not needed in all adaptations of the Screw but in this version its needed to make it work. You can see how the inside works below, with the water sitting and spinning in the dips of the screw.

Inside works:

 

Down below you can see the process of us building it, it took a long time for some steps because some of the plastic spiral discs didn’t fit perfectly into the tube so we had to sand them down which took some time that we didn’t think we would have to use for that. Its a basic design so we started with all our materials cut them down to size then we were ready to assemble, here I have pictured the parts used in assembly.

Then we cut out 12 of these discs that would make the spiral we would then glue them all to the wooden spoke:

Us painting the lever:

Final product before putting on lever:

http://www.livius.org/sources/content/plutarch/plutarchs-marcellus/the-death-of-archimedes/

http://archimedespalimpsest.org/about/history/archimedes.php

https://www.britannica.com/technology/Archimedes-screw

http://akvopedia.org/wiki/Archimedes_screw

http://www.softschools.com/inventions/history/archimedes_screw_history/14/https://www.historyanswers.co.uk/inventions/battering-rams/

http://archimedespalimpsest.org/about/history/archimedes.php

https://history.howstuffworks.com/historical-figures/archimedes-death-ray2.htm

 

Periodicity Project

Atomic Number Symbol Atomic Radius (nm) Ionization Energy (kJ/mol) Melting Point (°C) Density (g/cm3) Electronegativity
1 H 0.032 1312 -259.2 0.090 2.20
2 He 0.031 2372 -272.2 0.1785 0.00
3 Li 0.123 520 180.5 0.535 0.98
4 Be 0.090 899 1, 287 1.848 1.57
5 B 0.082 801 2,076 2.46 2.04
6 C 0.077 1086 3,550 2.26 2.55
7 N 0.075 1402 -210 1.251 3.04
8 O 0.073 1310 -218.8 1.429 3.44
9 F 0.072 1681 -219.6 1.696 3.98
10 Ne 0.071 2081 -248.6 0.9 3.98
11 Na 0.154 496 97.79 0.968 0.93
12 Mg 0.136 738 650 1.738 1.31
13 Al 0.118 578 660.3 2.7 1.61
14 Si 0.111 786 1414 2.33 1.90
15 P 0.106 1012 44.1 1.823 2.19
16 S 0.102 1000 115.2 1.96 2.58
17 Cl 0.099 1251 -101.5 3.214 3.16
18 Ar 0.098 1521 -189.4 1.784 3.19
19 K 0.203 419 63.5 0.856 0.82
20 Ca 0.174 590 842 1.55 1.36
21 Sc 0.144 630 1541 2.985 1.54
22 Ti 0.132 660 1668 4.507 2.54
23 V 0.122 650 1910 6.11 1.66
24 Cr 0.118 650 1907 7.19 1.55
25 Mn 0.117 720 1246 7.47 1.83
26 Fe 0.117 759 1538 7.874 1.88
27 Co 0.116 758 -205 8.9 1.91
28 Ni 0.115 737 1455 8.908 1.91
29 Cu 0.117 745 1085 8.96 1.90
30 Zn 0.125 906 419.5 7.14 1.60
31 Ga 0.126 579 29.76 5.904 1.81
32 Ge 0.122 762 938.2 5.323 2.01
33 As 0.120 947 816.8 5.727 2.18
34 Se 0.117 941 220.8 4.819 2.55
35 Br 0.114 1140 -7.2 3.12 2.96
36 Kr 0.122 1351 -157.4 3.75 3.00
37 Rb 0.216 403 39.48 1.532 0.82
38 Sr 0.191 550 777 2.63 0.95
39 Y 0.162 616 1526 4.472 1.22
40 Zr 0.145 660 1855 6.511 1.33
41 Nb 0.134 664 2469 8.57 1.60
42 Mo 0.130 685 2623 10.28 2.16
43 Tc 0.127 702 2204 11.5 1.90
44 Ru 0.125 711 2334 12.57 2.20
45 Rh 0.125 720 1963 12.45 2.28
            46 Pd 0.128 805 1555 12.023 2.20
47 Ag 0.134 731 961.8 10.49 1.93
48 Cd 0.148 868 321.1 8.65 1.69
49 In 0.144 558 156.6 7.31 1.78
50 Sn 0.140 709 231.9 7.31 1.96
51 Sb 0.140 832 630.6 6.697 2.05
52 Te 0.136 869 449.5 6.24 2.1
53 I 0.133 1008 113.7 4.94 2.66
54 Xe 0.131 1170 -118 5.9 2.6

Questions:

 

 

  • Atomic radius versus atomic number

 

A number of physical and chemical properties are related to the sizes of the atoms, but atomic size is somewhat difficult to define. There is no precise outer boundary of an atom. The radius is one half the distance between the centers of two adjacent atoms. The radius of an atom depends on the environment in which it is found. For bonded atoms, we customarily speak of a covalent radius, ionic radius, and, in the case of metals, a metallic radius. For atoms that are not bonded together, the radius is known as the van der Waals radius. For comparison, all radii in the above table are covalent.

    1. Which is the largest of the first 54 elements?

Rubidium (at 0.216 nm)

    1. Describe how the atomic radius varies within a period and within a family.

In a general description you can determine that atomic radii increases as you go from the top of your family to your bottom and as you go from right to left along a family generally, because as you might think as your number of protons increases so would your radii size, but no. As your number of protons goes up so does the attraction between the electrons pulling them tighter together so it actually gets more compressed.

    1. Use your graph to predict the atomic radius of the following elements:
      1. cesium  0.265 (b)   tungsten 0.145 (c) thallium  0.169 (d)   radon 0.140
    2. Which group of the main group elements contains the largest elements?

The group that contains the largest elements (when referring to atomic radii size) is group 1, this is because their valence shells contain one electron and that one electron pull is lessened by the full shell before (it’s hard for the electron to overcome, sort of “blocked out”), and also because it would take less energy to be unstable.

 

 

  • Ionization energy versus atomic number

 

    1. How would you explain ionization energy to your partner?

I would explain ionization energy to my partner like this: Ionization energy is the energy needed to take away  valence electron(s) from an atom. It is also highly dependent on the atomic radii, because the farther away your electrons are from your nucleus the easier it is for them to get “stolen” they can be considered the looser electrons.

      1. How does the ionization energy vary within a period and within a family?

Moving across the period, the ionization energy increases because the attraction of electrons to the nucleus also increases. In a family, when moving downwards the ionization energy decreases.

      1. Which element on your graph has the strongest hold of its valence electrons? Helium.
    1. (a) Write the electron configuration for chlorine. Cl: 1s2 2s2 2p6 3s2 3p5

(b) Which electron is lost when 1251 kJ/mol of energy are applied to a sample of chlorine atoms? 3p5 because 1251 kJ/mol is the amount of energy it takes to remove an electron from a neutral chlorine atom.

  1. Compare the ionization energies of metals to nonmetals.

Nonmetals and metals ionization can be compared to their atomic radii, because non metals valence electrons have stronger connections to their nucleus it takes more energy to pull them away, so instead they accept electrons to become negative ions. However metals have generally low ionization energies making it less work to take electrons from their valence shell, forming positive ions.

 

  • Melting point versus atomic number

 

    1. Describe the trend of melting points within a period

The strength of a metallic bond causes the melting point to increase among the periods. The atoms will minimize and get smaller as you move left to right on the periodic table.

    1. Which group of elements tends to have the highest melting points

The metals have the highest melting points because their bonds are so strong it requires more energy to change the state of the element.

    1. Tungsten is used in incandescent light bulbs because it has an extremely high melting point. Which element on your chart could be a reasonable replacement for tungsten? Why?

Carbon could potentially replace tungsten, because it has the highest melting point within the entire periodic table.

 

 

  • Density versus atomic number

 

    1. Describe how density varies within a period.

Often the density increases when you go top to bottom (of the family) and left to right (of the period), although solid elements will be higher than gaseous elements.

    1. Compare the densities of the elements in the second period with the elements in the third period.

From the second period to the third period, the density increases as you move further right.

    1. Assume that the transition metals given in the table are representative of the other members of this group. How do the densities of the transition metals compare with those of the elements in the main  group?Out of every group on the periodic table, the transition metals have the highest density. The elements in the main group are not as dense as the transition metals.
        1. Explain why aluminum and magnesium are more suitable than iron for use in some airplane parts.

      Magnesium and Aluminum are more suitable than iron in some airplane parts because they are both lightweight, but yet durable. Iron has a higher density than Magnesium and Aluminum (almost 4x as dense).

    2. Electronegativity versus atomic number

        1. Describe how electronegativity varies within a period.

      As you move left to right in each period, the electronegativity increases for each element.

        1. Describe how electronegativity varies within a family.

      As you move from top to bottom in a family, the electronegativity will decrease. This occurs because the valence electrons are further away from the nucleus.


      Graph A:

      Graph B:

      Graph C:

      Graph D:

      Graph E:

Flame Test Activity

Number 1:

Number 2:

Number 3:

Number 4:

Number 5:

Number 6:

Each compound that we sprayed into the bunson flame produced a varied colour because every element has its own set of energy levels, that correspond with different wavelengths to show up as a colour. The colour of the flame is dependent on the difference in energy between the two levels.