States of Matter Labs

          In the past week our science class did multiple labs about the states of matter. First, we did a lab about burning a candle. Before the candle was lit I noticed that the candle was waxy, yellow, and stood up straight. These were all physical properties of the candle. After lighting the candle it started melting and getting smaller. These were physical changes that occured. A chemical change that occured was that the candle began burning. The difference between chemical and physical changes is that physical means the appearance of the substance changes while chemical is when a substance is changed it to a different substance. Physical and chemical changes can be used to describe anything.

          Next, our science class did a lab about carbon dioxide and fire. To make the carbon dioxide we mixed vinegar and baking soda together. This made the substance to fizz. The new substance we made was a chemical change. We took the beaker holding the carbon dioxide mixture and held it over a flaming candle. This caused the flame to go out. The reason this happened was because fire is not supported by carbon dioxide.

          After that, we did a lab about marshmallows. Each person got one small marshmallow and one big marshmallow. The first thing we did was rip the small marshmallow in half. This was a physical change because the appearance of the marshmallow changed. Next, we put the big marshmallow over the Bunsen burner and burned them a little bit. This was a chemical change. The burned part of the marshmallow tasted bitter and burned. The rest of the marshmallow was sweet and fluffy. 

          The last lab we did also showed many examples of physical and chemical changes. In the beginning of the lab we had to crush up sugar cubes. This was a physical change because the size of the sugar cubes changed. Then, we took the crushed sugar and mixed it in with a glass of water. This was also a physical change because the sugar just dissolved. The last part of this lab was burning the sugar. Because the sugar was being burned, it was a chemical change. 

          All of these labs showed many examples of physical and chemical changes. The skills I learned during these labs can help me in my life. For instance, I can use physical and chemical properties to describe different things.

Pictures:

burned sugar

candle

marshmallow

Seperating Mixtures

1. To begin, remove the toothpicks from the mixture with the spoon.
2. Next, remove the beans from the mixture using the spoon.
3. Then, take out the large marble with the spoon.
4. After that, using the magnet, remove the iron filings.
5. Also, place the filter sheet over the beaker and pour the mixture into the beaker. This will separate the sand from the water.
6.Place all the items removed from the mixture onto the tray.
7. Take the mixture in the beaker and put it on the hot plate. Remember to turn the hot plate on.
8. Wait for the water in the beaker to evaporate. Now, the only thing left in the beaker should be salt that was mixed in with the water.
9. Turn off the hot plate and clean up your lab area. 
10. All seven parts of the mixture have been found!

Frog Dissection

          Opening up a frog and looking at its insides is not exactly the most appetizing thing to do before lunch. Last week, in science class, we dissected frogs. At first, I wouldn't even look at the frog. Finally, I mustered up the courage to poke it. After that, I was able to help cut it open and even help point out the organs. My groups frog was a female, so we named her Kermita. On the first day of dissection we only opened up Kermita and observed her organs. Kermita's organs seemed to all be squished in a small space. The first thing I noticed after opening up Kermita was the hundred of tiny, black balls that were everywhere. These were her eggs. I had predicted that her eggs would be enclosed in sac like ovaries in a human body. Instead, the eggs were everywhere. 

          The next day, my group took out the organs and tried to name them. We  noticed that the organs inside the frog were very similar to the organs inside a human body. Kermita had a heart, liver, stomach, lungs, and many other organs also found inside a human body. All of these organs have the same function in a frog as they do in a human. For instance, the liver makes bile in both frogs and humans. A few differences that Kermita had from a human were that she had oviducts, a cloaca, and smaller organs. The oviducts carry and transport eggs. The cloaca is where waste, eggs, and sperm exit the frog. In the end, the frog dissection was a lot of fun and helped teach our class about the organs in a frog.

Picture links:

Frog diagram

Jumping frog

Online dissection game:

http://frog.edschool.virginia.edu/Frog2/

The Circulatory System

Digestion Lab: Day 2

When we returned to science class today, not much from our lab had changed. In test tube A, the pepsin had crystallized around the egg whites. The pepsin in test tube B had dissolved into the water and made it foggy. Test tube C still had no reaction. Test tube D had the most change. The egg whites had shrunk a little bit and there were bubbles. The materials that were best at breaking down the egg were the hydrochloric acid and pepsin. Alone, the pepsin did not do much to break down the egg white.  Hydrochloric acid, alone, also did not do much. Together, they had broken down the egg a little bit. In the end of the lab I concluded that the chemical digestion of protein in food is a slow reaction. This is my conclusion because none of the test tubes had broken down the egg whites.

Digestion Lab: Day 1

Today in science class we began a lab. This lab was about the human digestive system’s way of breaking down food. When doing this lab we used hydrochloric acid, pepsin, boiled egg whites, and water. The hydrochloric acid represented the acid in our stomach that helps break down food. The boiled egg whites represented the food in our stomach. First, we placed egg whites and pepsin in test tube A. After a few minutes the egg whites started turning a light yellow color. Next, we put water, pepsin, and egg whites in test tube B. The water sat at the top while the pepsin sank to the bottom of the test tube. Then, we placed only egg whites and hydrochloric acid in test tube C. There was no immediate reaction in test tube C. In test tube D we put hydrochloric acid, pepsin, and egg whites. The mixture inside the test tube bubbled a little. I predicted that the next day, test tube D would have been the only test tube that had broken down egg whites in it. In the end, we used litmus paper to test the presence of an acid. Litmus paper turns pink when it touches an acid such as hydrochloric acid. Test tubes A and B tested negative for acid, but test tubes C and D tested positive for acid.

Chicken Wing Anatomy Lab

Last week my science class watched our teacher dissect a chicken wing. We were not allowed to touch this chicken wing because it was raw and could contain some disease. The first layer of the chicken wing was the skin. The skin was a light yellow and look like it had small goose bumps on it. This layer was attached to muscle tissue. Then, our teacher showed us the muscles of the chicken wing. These muscles were pink and looked smooth.  These muscles control our movement and they are connected to bone tissue. Tendons are what attach muscles to bone. We also saw fat tissue which was white and connected to muscle tissue. Our teacher pointed out a few ligaments. The ligaments were white and shiny. They were connected to bone tissue and covered joint surfaces. Cartilage was the last tissue we observed. It was white and seemed slippery. The cartilage helps bones move without touching each other and causing damage. During our chicken wing lab we did not find any nerve tissue in the wing. The reason we did this lab was to show how human arms are similar to chicken wings. Human arms are similar to chicken wings is because they also contain ball and socket joints. A difference between them is that our arms have different proportions than chicken wings.