Mini Project-Which coin drops fastest?

Which coin drops fastest?

• Put a coin at the edge of a table.


• Put the edge of a ruler behind the coin, with the rest of the ruler extending out over the table edge at an angle.


• Put another coin on the end of the ruler that extends beyond the table edge.


• Take a second ruler and hit the first ruler (on the edge sticking out beyond the table edge) so that the first coin is thrown off the edge of the table and the second coin drops off the ruler.


• You have to listen for the results so you want to do this over a hard floor.

Which coin hits the ground first?

Science:

The coins start from the same height off the ground and are the same mass and shape, so gravity and air resistance worked on them in exactly the same way. Even if an object is thrown straight out, it will fall to the ground in exactly the same amount of time as an identical object that is dropped - the acceleration toward the ground that the objects experience as a result of gravity causes them to hit at the same time.

Mini Project Pile driver

Pile driver

• Fill a plastic jar with rice,


• carefully jab a knife into the rice five or ten times.


• The rice will settle a bit, then add more rice.


• Continue until no more rice can be added.


• Then quickly jab the knife into the rice and lift.

What happens? Why?

Science:
The rice gets more and more packed down by repeated stabs from the knife until the rice is so compact that it presses against the blade of the knife with enough force to overcome the pull of gravity on the jar.

Chem Standard 8c and 8d

The role a catalyst plays in increasing the reaction rate.

The presence of a catalyst increases the reaction rate (in both the forward and reverse reactions) by providing an alternative pathway with a lower activation energy but is chemically unchanged at the end of the reaction. When the reaction has finished, you would have exactly the same mass of catalyst as you had at the beginning.

Role of activation energy in a chemical reaction.

Activation energy is a term introduced in 1889 by the Swedish scientist Svante Arrhenius, that is defined as the energy that must be overcome in order for a chemical reaction to occur. Activation energy may also be defined as the minimum energy required to start a chemical reaction. The activation energy of a reaction is usually denoted by E_a, and given in units of kilojoules per mole.

Activation energy can be thought of as the height of the potential barrier (sometimes called the energy barrier) separating two minima of potential energy (of the reactants and products of a reaction). For a chemical reaction to proceed at a reasonable rate, there should exist an appreciable number of molecules with energy equal to or greater than the activation energy.

The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner. The blue flame will sustain itself after the sparks are extinguished because the continued combustion of the flame is now energetically favorable.

mini projects and map making

This week we did more glass bending during class. We also had to make a map for the Mills Canyon Creek trip on Google maps. I also finished one of the mini projects out of the three that was due next week. My project was on the speed of the jars that roll down a binder, with one jar filled with water. Here is my map:

View Mills Creek Canyon in a larger map

Mini Project: Racing Jars!

Today on Wednesday March 5, 2010,I took two identical clear-glass jars and raced them down a binder to see which one went down the fastest, with one of the jars filled with water.
(Picture taken by Angelica Choi)

• leave one empty, and fill one with water.



• Put the lids on both jars and tighten.



• Place a large, three-ring binder on a level floor



• start the jars from the top of the "ramp" the binder forms.



• Release them and watch what happens.

Which one gets to the bottom of the ramp first? Which one rolls the farthest?

Science:

At first, the water-filled jar moves down the ramp faster than the empty one. This happens because its weight is evenly distributed throughout its volume, thanks to the water inside it. The empty jar's weight is all in the glass outside so it doesn't roll quite as fast. But as the jars begin rolling on the flat surface, the greater weight of the full jar causes friction between the jar and the floor as well as friction between the water and the inside of the jar. The full jar slows down, allowing the lighter, empty jar to take the lead!

Bending Glass

This week we watch our classmates bend glass. I thought it was very cool and interesting. I watched people file the glass tube first and then they break it inward so the glasses won't fly everywhere. then they hold the glass piece up to the fire and heat it up until it was very malleable. After a while, it was very bendable and I watched them bend the glass into very interesting shapes.
But first of all we must remember Safety First!!!

I Propose We make a golden rod paper that looks like it is bleeding

Goldenrod paper looks like it is bleeding when exposed to basic solutions.
Here's a video: enjoy!

Materials:

• Goldenrod paper
• Cotton balls
• Ammonia-water solution (household ammonia from the grocery store)
• Safety glasses
• Candle

Procedures:

1. Place a piece of goldenrod paper on the table. Make sure that table is clean and the work surface is dry.
2. Place a drop of water on one of the corners of the paper. Does anything happen?
3. Fill a jar with a small amount of ammonia water. Dip a cotton ball in the ammonia water and wipe it across the top portion of the goldenrod paper. Save the bottom half of the paper for step 5. Does anything happen?
4. As you continue to wipe designs on the goldenrod paper, notice that the paper does not stay red forever. What is causing the paper to change back to yellow?
5. Use the old piece of wax candle to write a secret message across the bottom half of the paper.
6. Wipe the cotton ball with ammonia water across the secret message to see what develops.

Safety Precautions:
1. If you get the basic liquid on your hands don't touch face or eyes.
2. Watch out for he sharp corners of the paper so you won't get a paper cut.

Scientific Principles:
1. Certain brands of goldenrod paper contain a special dye that turns bright red in solutions that are basic like ammonia water or washing soda.
2. The paper turns back yellow with an acid like vinegar or lemon juice.

Star testing week

This week was very hectic because the school schedule was messed up and i forgot what class was gonna come next. I think i did very well on the star testing because i thought it was pretty easy. We also get to go on a class field trip on April 29 at Mills Creek Canyon. I hope we get a good experience from this trip and i can't wait to go and learn from this lab we're gonna do.

David Webb Presentation

On Wednesday we had a guest visitor, and he demonstrated about air molecules and pressure in a vacuum. We saw how a can has been crushed, a marshmallow that has been super sized, then shrink, and a ballon that was blown with a knot already tied. It was really interesting and it helped me better understand how pressure works.

Pressure and Temperature

This we did a lab on Pressure and what it can do. We saw how pressure can crush a can just by heating it up and putting it in a cold bucket of water. Yesterday we measured the pressure of air in a glass tube while putting it in different temperature of liquid.

Equilibrium

The following Monday was the test on Energy. We used the fromula Q=mc deltaT. We also learned about exo and thermo energy. We also learned about activation energy. We watched a video called Molecules in Action. The lab we did invovled phase changes.

Heat energy and elephant toothpaste

We got a new packet and it was about heat and energy. and also did a lab involving the three phases of water, which is gas, water, and liquid. We got a ice and put it in the beaker, then heat it until it became a liquid, then gas. We measured the temp every 15 secs and the temp changed often. The elephant toothpaste was such and exciting demo lab to see because we saw mr. olson mix a whole bunch of liquids together and saw the toothpaste form and heat coming out from it.

Thermochemistry

We conferred heat from hot to cold objects and also about heat and energy. We did a lab and weighed cups and used the flame (Bunsen burner) and got a new packet which is about the flow of energy and it was due two Fridays ago. This week was mainly about thermochemistry.

Stoichiometry Na2CO3 plus HCl

We measured and combined hydrochloric acid and sodium carbonate into a beaker and watched the bubbles form. we also had to weigh the mass of all the chemicals and also the beaker. and recorded all the data. We also have a test tomorrow and the yellow packets are due tomorrow. Today we are puting the periodic table into the cbook also.

Stoichiometry

This week we learned about Stoichoimerty. Yesturday we measured, weighed, and burned a magnesium ribbon. After we watched it turn into magnesium oxide. While it was burning we had to watch it carefully and lift the lid until it doesn't have any smoke or lighting up.

Reactions 2 packet

Last week we got another packet and we did it during class. We learned and did balancing many different kinds of equations. We balanced Synthesis, decomposition, single replacement, double replacement, and combustion reactions.

Solutions and pH test

This week we took the test on Monday. This week we also learned how to balance equations. We used cubes to help make it more easier to balance. Today we turned in our reactions packet and got a new reactions 2 packet. M=mol/L. We also learned how to do titration and dilution equations.

acids and bases lab

This week we did a lab on acids and bases and saw how each solution changed colors when we add the acids and bases to them. There were four stations and we switched stations after we were done with each part. We had two worksheets that we have to fill and turn in on Friday. Electrolytes are solutions that conduct electricity very well. The more ions form, the better the conductivity.




http://mail.colonial.net/~hkaiter/science%20images/phdiagram.gif

Make a solution lab

This week we did a lab mixing coblat chloride and water, but we need to add just enough water and let mr.olson analyse it with the spectronic-20 machine.
We also mixed out the volume of 0.0025M in a gradualted cylinder and mixed it with water. This week we also larn how to dilute a substance.

like dissoves like

This week we worked in a packet and i learned about solute and solvent. And we turned in the packet with our worksheets that were due today. yesturday we did a short lab with a purple substance and we added water to each one to make it more clearer. Dissolving it having solute in a solution (solvent) in the process of going into solution.

http://www.education.vic.gov.au/images/content/studentlearning/scicontinuum/permanganate.jpg