Substantive Education

April 26, 2009

Just saying

Filed under: Ancient Rome — kbagdanov @ 2:51 am
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Mean Verbal SAT scores for 2006:

Spanish Students: 577
French Students: 637
German Students: 632
Hebrew Students: 623

Average for all students: 503


April 22, 2009

Using the Scientific Method to do Science Fair Projects


Scientific Method

I talked about the Scientific Method in my post on Gardening Part 2…and realized that it is a topic that seems to generate a lot of confusion. I thought I would break it down for you here using a simple elementary school experiment. For those of you with children who have to do science fair projects I’ve chosen to use one of my sons to illustrate a couple of points. First, don’t be to quick to correct your children’s hypothesis’s when you see them heading in the wrong direction. Scientist learn as much from failed experiments as they do from ones that work. Second, do help your children identify variables that might change (explanation later) that is an area that most kids can’t see right away and need practice to understand.

One of my sons did a Science Fair project on how fast different liquids would freeze. (I could not find any pictures of this experiment … but I have included some other photos of past projects to give you an idea of how their finished boards looked. Gluing and designing the display is half the fun.) He was in early elementary school. Now that he had picked a topic…often the hardest part, he needed to start doing some research. Depending on your child’s age, and how much time you are investing, it is a good idea to have your child find several different kinds of sources. For instance, they can look up information in a book, search the internet, and maybe interview an ‘expert.’ (like a physical science teacher). While we did our research one of the things that he discovered was that salt (sodium) makes things freeze slowly.


Caleb and a science fair project on filtering water.

The next step is to come up with an Hypothesis…this is an educated guess. You guess, from the research you have done, what will happen. Well, my son was quite young, and although his research had said that sodium would make things freeze more slowly he still hypothesized that the milk would freeze quicker because it started out thicker, or more solid. When he wrote out his hypothesis for me that is exactly what he said. ‘While milk has sodium which slows down freezing I believe that the milk will freeze faster because it is already partially solid.’

Now we needed to design an experiment. This is a tricky step with many things (variables) to consider. My son chose several different liquids; tea, water, apple juice, and milk. We decided we would put some of each into ice cube trays and then check on them every 15 minutes and record what we found out.

While that gave him a general idea of his experiment, there were still a few things he needed to account for. He needed to be sure that he had controlled as many variables as possible. For instance, he decided that all of the liquids needed to start out at the same temperature, so we let the trays sit out on the counter until all of the liquids were at room temperature. He used a thermometer to determine they were all the same. He also carefully measured the amount of liquid put in each part of the trays…different amounts of liquid would yield different results. As with all good experiments he filled up several trays so that he had performed the experiment repeatedly thereby showing that his results would be consistent. Hopefully that clears up what I mean by accounting

Joseph and a project on the variety of animals in tidepools.

Joseph and a project on the variety of animals in tidepools.

for variables.

Your child needs to carefully write out the directions for their experiment (including all of the directions to account for variables.) Help them understand that the directions should be so clear that someone else doing the experiment would know exactly what to do.

Now it is time to collect data. Your data should be in a written record and if possible recorded in a concrete measurement. In our case, he wrote down a description – frozen crystals are beginning to form- and estimated what percentage of the liquid had become frozen. We did this every 15 minutes until all of the liquids were frozen. Help your child to understand that at this stage they are just recording the data, not interpreting it.

Levi with a project on dental gum removing plaque.

Levi with a project on dental gum removing plaque.

Next, we want to analyze the data. If your child is old enough to do math this is a great time to work at getting averages of your results. For instance, if we performed our experiment 4 times and the apple juice took 35 minutes to freeze in one try, 34 in another, 37 in another etc. we would add up all of those results and divide to get the average of our experiment. This gives a practical application to all that math they are learning. Most science fairs require the data that you analyze to be displayed on graphs. Luckily there are many online programs that can help you with graphs, although I found that especially for younger children, the exercise of making the graph is very instructional.

Once we have analyzed the data we are ready to interpret. Basically, was your hypothesis correct. As you might have guessed our hypothesis was wrong. The milk was by far the slowest liquid to freeze, so in his interpretation he said, ‘Although I thought that the milk being thicker would make a difference it didn’t, the sodium in the milk kept it from freezing.” As it turns out he won with this project at the fair we were at…the object is to follow the scientific method and learn from

Caleb and his wetlands experiment.

Caleb and his wetlands experiment.

it…not to get a ‘right answer’.

We aren’t quite done yet, the next step is to examine your experiment and decide if you could pursue it further what would you do – maybe find several liquids with sodium in them and test whether the amount of sodium made a difference.

Just about anything your kids are curious about can make a good science project. We’ve done experiments with friction using race cars going down slopes of various materials, where banana’s brown quicker, what surfaces snails like to crawl on, what foods rats prefer, whether the SPF in suntan lotion makes a difference, and whether fertilizer affects our wetlands. I’ve seen projects on belly button lint (no kidding) and the accuracy of shotguns. This is a great way to let your children’s natural curiosity lead their studies.

Where we compete the kids have to show their workbook (not a finished cleaned up copy – that is there too- but a messy first draft) to show that they did the work, not mom and dad. In their books they acknowledge what help they received, like typing, math they didn’t understand etc. The idea is to have your child do all of the work possible, but where they need help to offer assistance. Be careful not to ‘overhelp’. Let the project be theirs.

By the way, a fun start to a project is using red cabbage as an indicator of ph balance.  If you want more information about how to do that check it out here. There is also information about how to break water molecules down into hydrogen and oxygen here.  This information can be taken even farther if you catch the bubbles escaping in test tubes…you will see there is twice as much hydrogen as oxygen…

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