Archive of ‘Science 7’ category

Review of Grade 7 Science

This year in science, I have really enjoyed the experiments that we did. I especially enjoyed the loremite experiment, because we got to do the different steps by ourselves mostly (and I broke a mortar). I also learned a lot from that experiment. The thing I found most interesting this year was probably the asteroid mining project. I hadn’t even heard of it before the assessment, so I learned a lot of new and interesting things. I think that the most challenging thing for me in science this year was preparing for the exam. Although I ended up doing well on the exam, I wasn’t sure exactly what to study for, so I was worried that I hadn’t prepared for the right concepts. Because of this I had to guess some of the answers on the test, but luckily it was fine. I think I improved on the style of writing up experiments and scientific essays. Last year I didn’t really know how to properly do this, and I think I improved a lot this year with the practice of different assessments. Next year, I want to further improve using information from a text in my work, perhaps using in-text referencing. This year Mr. Fedley always suggested that I should do that, but I always forgot when I actually was doing the work.

Light

In science recently, we have been looking at light and how it is reflected and refracted through objects. I have decided to research telescopes because I feel like they are interesting, as they are our gateway to outer space. First of all, reflection is when light bounces of an object and reflects at a different angle. For example, if you shine a light on a mirror it will reflect in another direction. Refraction is when light passes through a new object and bends when it comes out of it. For example, if a light goes through a clear plastic object, it will go in a different direction. Telescopes can do both of these things, although there are different types of telescopes for both.

Most of the time telescopes just refract light. When it goes through the lens it bends to create the image that we see through it. This makes something far away seem a lot closer than it is. In reflecting telescopes, curved mirrors are used to magnify the light. This works by the light bouncing of both mirrors, before going through a refracting lens. The first telescopes were recorded in 1608 in the Netherlands. The credit goes to three different people for inventing it: Hans Lippershey, Zacharias Janssen and Jacob Metius. However, shortly after, Galileo created his own version and greatly improved it in the following year. This is the telescope that became very famous.

An obvious limitation of telescopes is that there is a certain point where you can’t see any closer. By this point the image will get too blurry, and you won’t be able to see clearly. In a simple refracting telescope, the light goes into the objective lens, which gathers it and bends the light into focus. At a certain focus point, the light coming in from different directions meets in the middle to create a bright point. At the very front of the telescope there is an eyepiece, which magnifies the focused image to the size of the person’s pupil. Telescopes are actually a lot more interesting than they seem, as they can use light in different ways to display an image.

The process described above

 

Image Source:

“Akash Ganga: Centre for Astronomy (AGCA).” Akash Ganga: Centre for Astronomy (AGCA). N.p., n.d. Web. 06 June 2013.

Atoms, Compounds and Mixtures

What is an atom? Describe the different parts and state where they can be found in an atom.

Atoms are a collection of tiny bits of electricity called protons, neutrons and electrons, which can only be seen under a microscope.

What is an element? Give three examples of an element and give a use in the real world for each of these elements.

An element is a substance that contains only one kind of atom. Titanium, potassium and gold are all elements. Titanium is a metal and is used in different things, potassium is used to blow things up and gold is a very valuable metal that is a popular part of jewelry.

What is a molecule? Give three examples of a molecule and give a use in the real world for each of these elements.

A molecule is a group of atoms bonded together, for example, oxygen, C2 and H2O. We need oxygen to breathe, C2 is used in graphite and we need water (H2O) to drink.

What is a compound? Give three examples of a compound and give an use for each one.

A compound is a substance formed from two or more elements chemically united, and one example is CO2. We exhale this, and it is used in dry ice. Another example is NH3, which is used in fertilizing. The third example is also a molecule, H2O. Again, we need water to survive, and we use it in many different things, including food.

What is a physical change? Give an example.

A physical change is when there is a change of state. For example, solid to liquid, liquid to gas, and the other way around. For example, when people make ice cubes a physical change occurs (liquid to solid). No mass is lost in this process.

What is a chemical change? Give a few different examples.

A chemical change is when something happens to make a new substance, and the process cannot usually be easily reversed. For example, if you bake a cake, there is a chemical change, because you can’t un-bake it. Another example of a chemical change is if you cook an egg; you can’t reverse this process. Again, no mass is lost.

Science Assessment Task: My Food

For our first assessment task in science, we had to make a presentation about a type of food. Here is the link to my presentation.

Altogether, I think I spent about two weeks on the project, but we did a lot in class. First we had to choose a food to do our project about, and then we had to start investigating and answering questions about nutrition facts. Once we had finished that, we did the actual food tests, to see if our food had fat, starch, protein and/or glucose in it. Then I wrote up the results and answers in a keynote presentation.

It was quite an interesting unit for science, because last year we mainly studied things that didn’t have much to do with ourselves, whereas looking at what is in your food definitely connects to your life. Food is a strange topic, and a lot more complicated than it seems. We learned a lot about how energy in food is broken up, what sorts of nutrients are in it, and why you need them to stay healthy.

The part of this assessment task that I am most proud of is probably my final product, because I think I did a good job at setting everything up with the time we were given to do the actual project. If I did this again, I would probably try to spread out my work time a bit better, because I ended up almost having to rush things in the end. Overall, though, I think it was a good job for our first assessment task of the year.