Archive for the ‘Science’ Category

#15 Freezing Alcohol

Monday, November 10th, 2014

freezing-alcohol

This post contains affiliate links. I was compensated for my work in writing this post.

Today we are doing a “Freezing Alcohol” experiment where we will put different amounts of alcohol combined with water in the freezer to see which will freeze first. My younger two children are using Christian Kids Explore Chemistry by Bright Ideas Press, and this is one of the experiments in the book.

Grab three plastic containers with lids. You need lids because alcohol evaporates so easily, and we don’t want the alcohol to evaporate out of the containers and affect our results.

Label the three containers by writing on paper with a black permanent marker. Attach the labels with packing tape. Here are the three labels:

  • Water only
  • 70% Isopropyl Alcohol
  • Water + 70% Isopropyl Alcohol

The water only container is the control. We will see how fast normal water freezes and compare that to the amount of time it takes for alcohol to freeze, if it freezes at all.

Grab your rubbing alcohol from your medicine cabinet. This alcohol will say “70% Isopropyl Alcohol.” Pour the alcohol into the second container.

The third container should have half alcohol and half water. If you put 100 ml of water in the first container and 100 ml of alcohol into the second container, you will want to put 50 ml of water and 50 ml of alcohol into the third container.

freezing-alcohol-2Place all three containers into the freezer and wait two hours. Then pull them out and remove the lids to see what is going on. The first container was frozen solid. The second container was sort of frozen on the bottom, but liquid on the top. The third container was completely liquid with no ice whatsoever.

Even after 24 hours, we have similar results, except for the second container. Take a look:

Alcohol definitely has a lower freezing point than water does. In fact, a normal household freezer (which is around 0 degrees) will never be able to freeze the alcohol unless the temperature of the freezer is lowered considerably! Of course, you would not want to do that to your freezer, or all your food would get freezer burn!

freezing-alcohol-3

#14 Saturated Solutions

Monday, November 3rd, 2014

saturated-solutions

This post contains affiliate links. I was compensated for my work in writing this post.

Today we will be making saturated solutions. What is a saturated solution? It’s when the water is holding the most of a substance that it possibly can. We will be making a sugar solution and a salt solution, and we will do a fun identification game at the end, to see if we can identify which is salt and which is sugar. We are using Christian Kids Explore Chemistry by Bright Ideas Press, and this experiment will help you to understand saturated solutions.

I labeled the four glasses before doing the experiment. Two were labeled salt and two were labeled sugar. I put the labels on the bottom of the glasses. I used masking tape and permanent marker.

We poured water into each of the four glasses. Then we placed one teaspoon of salt into the water and stirred it. We placed a second teaspoon and a third teaspoon and so on until the water would no longer hold any more salt. At this point, some of the salt will fall to the bottom because the water itself can hold no more salt. The water is now saturated with salt. Do the same to another glass of water.

Using sugar, place the sugar, one teaspoon after another, into the water, stirring the water after each teaspoon. As soon as the water will hold no more sugar, the water is saturated with sugar. IV’s at the hospital are filled with glucose, so what is pumped into your body when you want to faint is similar to this saturated sugar solution.

saturated-solutions-3Once you have two glasses of sugar solution and two glasses of salt solution, have your kids close their eyes. (Blindfold them if they look like they are cheating with one eye open.)

Slide the glasses around, shuffling their order so your kids can’t tell which solution is which. Now have your kids open their eyes, or take off the blindfold. Have the kids try to figure out which solution is which based on smell. Can you do it?

Now try to identify which solution is which by tasting them. The salt water is really strong and will remind you of ocean water crashing over you. The sugar water is certainly easy to identify, too!

You can watch this experiment here:

#13 Saltwater Experiment

Monday, October 27th, 2014

saltwater-experiment

This post contains affiliate links. I was compensated for my work in writing this post.

Today we are doing a fun saltwater experiment where we freeze water with different amounts of salt to see which solution freezes faster. Yes, it’s like a race to see which freezes first! This experiment is from Christian Kids Explore Chemistry by Bright Ideas Press, and we have been working our way through the fun experiments in this book.

First you will want to get four plastic cups and label them by writing on a piece of paper with a black marker. We attached the labels to the plastic cups with packing tape. These are the labels:

  • Water
  • 1 teaspoon salt + water
  • 2 teaspoons salt + water
  • 3 Teaspoons salt + water

Pour water into the four glasses and measure the correct amount of salt to put into each glass. Stir the solutions until the salt has dissolved. Now place them all in the freezer. If your freezer is a drawer like mine, you will need to lodge the glasses in place with a frozen lasagna or other large froze object. (Watch the video to see how I kept the glasses from falling over in the freezer.)

Which glass of water will freeze first?

freezing-saltwater-experimentAfter two hours, the glass with only water in it was solid ice. The glass with one teaspoon of salt in the water was a little less solid than the first glass. You could scrape it like a snow cone because it wasn’t completely solid. The glass with two teaspoons of salt was even less frozen, and the one with three teaspoons of salt was not frozen at all when I broke through a thin layer of ice on the top. Under that thin layer of ice was liquid.

The more salt that you have in the water, the longer it takes to freeze. After four hours, all the glasses were more frozen, but the one with three teaspoons of salt was still quite liquid.

After 24 hours, we checked the glasses again, and all of them were finally solid. Take a look:

So what does this mean? Salt lowers the temperature at which water will solidify, so when you are making ice cream, for example, you can put salt on the ice to keep the ice cold longer.

You can also use salt to melt snow in your driveway in the winter.

saltwater-ice-experiment

#12 Testing Charles’s Gas Law

Monday, October 20th, 2014

charles's-gas-lawThis post contains affiliate links. I was compensated for my work in writing this post.

My kids tested Charles’s Gas Law with a fun experiment involving a glass soda bottle and a balloon. We are using Christian Kids Explore Chemistry by Bright Ideas Press. This is one of the experiments in the book.

What is Charles’s Gas Law?

I suppose we should define Charles’s Gas Law before we conduct our experiment. Charles’s Gas Law: If the temperature of a gas is increased, the volume of the gas will increase.

Knowing this law will help you predict what will happen when you place a glass bottle in the refrigerator, then set it in a bowl of boiling water with a balloon over it. The gas inside the bottle went from cold to hot, which means the air inside the bottle is expanding. This is the reason the balloon immediately stands up, because the expanding air needs to go somewhere.

balloon-experiment

Then you place the bottle into ice water, and see the balloon deflate again. You might need to place it in the refrigerator to see the full effect of the deflated balloon.

Steps for Charles’s Gas Law Experiment

  1. Place a glass bottle into the refrigerator for at least one hour so the air inside it is nice and cold.
  2. Place some hot (not boiling–it melted our first balloon!) water in a bowl, and place ice water in another bowl.
  3. Grab the bottle out of the refrigerator and put the balloon on the top of it.
  4. Place the bottle into the hot water and watch the balloon stick up suddenly.
  5. Now place it into the ice water. Wait for a while, and notice there is less air pressure in the balloon.
  6. Place the bottle back into the fridge, and an hour later, voila! A limp balloon will cause your kids to squeal and point. Indeed, Charles’s Gas Law is correct!

Video of the Experiment

Take a look at the experiment:

The bottle is too small to actually inflate the balloon for real, but I’ve done a similar experiment, throwing dry ice into the bottle and placing a balloon over the top. The air expands way more explosively, and the balloon actually inflates!

*Always make sure to wear gloves when touching dry ice.*