Tag: Science Experiments

I had a few experiments in my back pocket for this week, but when I asked Sam what kind of thing she wanted to try, she raised her fist in the air and said “Something with FIRE!”

Okay. I can do that.

Here’s the setup:

• oil
• A glass bowl
• a short candle
• Something to prop the bowl up between (I used two rectangular dishes per the picture below)
• food coloring

I poured a few inches of oil into the bowl, propped it up between the dishes, and put the lit candle underneath it. I then explained to Sam that when the oil at the bottom, nearest the flame, heated up, it would rise up to the top. Then, as it cooled, it would move back down. To help us see this, I used the dropper to put a few blobs of red food coloring in the oil.

At first I was kind of worried, because nothing seemed to be happening at all. I added a second candle, though, and before long the little red blobs began to “blorp” up to the surface in sputters, then scatter and slowly descend just as promised.

I explained to Sam that this kind of hot/cold circulation happens all over in nature, including in the air (which affects weather) and the ocean. Here’s her journal entry:

Experument 9: circulating het …It blrpt up all the letl dots. Its lic ther’s a invesable lin that the bobles go up. It blorpt. Hot oyl flots to the top.

As a bonus, Sam drew a little picture of the setup, which was nice.

Continuing my blogging project for 2011 where I do a science experiment per week with my seven year old daughter.

Okay! Science experiment! Let’s see, Sam was asking about sunsets the other day, so let’s do this one about diffusion of light. Supplies:

1. Jar of water
2. A flashlight
3. Milk

The idea is that the flashlight shines straight through regular water, but mix in a little milk, and the solution starts to diffuse the light, turning it from cloudly white to brownish red.

Only …it totally didn’t work. What we got was light shining through white, milky water. This is hardly exciting nor educational. I declare the experiment a failure, and Sam scribbles through the notes she had in her journal and writes “FAIL!!!” at the top. I chide her for her overuse of exclamation points. Multiple exclamation marks are a sure sign of a diseased mind, a great man once said. I think it was Jesus.

Anyway, while Sam drew frowny faces in the margins of her journal, I set up a backup experiment: Making a Rainbow! Supplies:

1. Shallow pan of water
2. A small mirror
3. That flashlight again
4. A thick piece of white paper

I angled the mirror in the dish of water and shined the flashlight at the submerged part while holding the white paper above the dish. Instantly, a brilliant, sharply defined rainbow sprang to life on the crisp white paper …is what the book said would happen. Instead, nothing happened, and in copious amounts.

Sam sighed loudly and started scribbling “FAIL AGAIN!” in her journal while I muttered halfheartedly about null results and the file drawer problem. I then flipped through the book some more until I found something that was both simple and had to be foolproof: the refraction of light.

Take glass. Fill halfway with water. Put friggin button in the friggin glass. Look, two friggin buttons. It’s friggin refraction!

BEHOLD!

Sam’s final journal entry, in full:

Experumint 8 FOR THE LAST TIME: Seeing dobl. It looks like thar are two butins. This is becas light bens wen it goes throo wotr. This is cald refraction.

I’m going to have to put a bit more thought into next week’s activity.

Continuing my blogging project for 2011 where I do a science experiment per week with my seven year old daughter.

This week I continued rooting through the pantry for supplies, and decided to team Sam about density and why some things float. This was really simple as far as experiments go, but it turned out to be Sam’s favorite yet, plus I was able to get her sister Mandy involved as well. Here’s the supplies:

1. A tall glass
2. Water (I added red food coloring to mine)
3. Dishwashing soap
4. Cooking oil
5. An assortment of small objects that you don’t mind getting oily, oily and wet, or oily, wet, and soapy.

Any three (or more) liquids of different densities that don’t dissolve in each other would work, but these three worked for me. And yes, it’s too bad I couldn’t get them to go green, yellow, red like a traffic light, but I am unable to control the density of these liquids. FOR NOW.

Sam was extremely curious as to why the liquids separated out and didn’t mix, especially after I poured a bit of water on top and she watched it flow down through the oil to join the red layer:

I explained that the three liquids all had different densities, which kind of meant that they were more or less packed together in the same space. Denser liquids weight more than less dense materials, and less dense materials float to the top of denser ones. Sam seemed to get it and inspected the glass carefully while I had panicky premonitions of trying to clean up oil, soap, and water from the kitchen table:

The next part of the experiment was to drop various items into the glass and see where they settled. I explained that this would tell us how dense the objects were, since like the liquids the solids would float on top of anything that they were less dense than. The objects I gathered included a penny, a piece of carrot, a plastic bead, a rock, a marshmallow, a piece of potato, a Lego block, a piece of rubber, and a piece of macaroni. For the first few, I had Sam make predictions about how far down they’d sink, then I had her record her observations.

She absolutely loved doing this, and since this was an activity that basically involved dunking things in other things, Mandy was both able and willing to participate. I think part of the appeal here is that kids love making predictions and repeating trials with slightly different conditions. In this way, they’re natural scientists, and it’s not far removed from how babies learn to do, well, everything. When you’re a kid, most of what you encounter is new, and the only way to figure it out is to do trial after trial and make observation after observation.

Once they had exhausted my supply of small objects, they asked if they could find other stuff to drop in. When I said they could, the first thing Sam nominated was my iPod, which was one sacrifice I was not prepared to make for science. At any rate, not only did Sam love this, she proclaimed that it was the most fun experiment we had done to date. Here’s her journal entry in full:

Experiment 7: Density.
Things that are less density float on things that are more dense. I prdect the marshmallow will float on the oil. I prbekt that the rock will go to the dotem. The peanut floated in the water. The butt rock fell to the botem.

And, as a footnote, Sam did indeed write “The butt rock fell to the botem (sic).” She and Mandy have named the rock in question thus because a streak of quartz in the lower half of the rock does indeed look like a generous backside. Since it was for science, I allowed it.

Continuing my blogging project for 2011 where I do a science experiment per week with my seven year old daughter.

Since we consumed a gas in last week’s experiment, I thought this week we could do the opposite and create a gas using those old standbys: vinegar and baking soda. Since we were at Grandpa’s house this week, it made for a nice easy experiment and I got to raid his kitchen cabinets for supplies:

• Vinegar
• Baking Soda (sodium bicorbonate)
• A balloon
• A bottle or vase with a narrow mouth

(Sorry for the quality of the photos. I forgot to bring a CF card for my camera, so I had to use Ger’s point-and-shoot and backlit lighting to boot.)

I explained to Sam the concept of a reaction –that some things change when they mix with or even just touch other things. That change create a lot of interesting things, including creating a gas. I told her that baking soda and vinegar would make a gas when they mix, and asked her what she thought would happen if I mixed them together and put a balloon over the mouth of the bottle. Sam wrote in her journal:

Experument 6: Makeing gas. I prdikt that the dlon will explode.

Yes! Explosions! With that in mind, I poured a few cups of vinegar into the bottle, filled the balloon with baking soda, and stretched the tip of the balloon over the mouth of the bottle without letting any spill in. I then told Sam to upend the balloon and dump the powder in:

The reaction –in all sense of the word– was pretty great. The mixture fizzed violently and the balloon started to expand like a big fat exclamation mark, which actually caused Sam to shriek and dive under the table, fearing that her prediction was seconds from coming woefully true:

Honestly, I got kind of alarmed myself for a second; the book hadn’t provided any guidance on the amount of mixture to create, and I had just begun worrying about the best way to get globs of baking soda and vinegar off of a ceiling when it finally eased off. Instead, I ribbed Sam about her squeamish reaction and made her practice her maniacal mad scientist laugh and give me ten good shouts of “I’LL SHOW THEM! I’LL SHOW THEM ALL!” to make up for it.

Then she finished writing in her journal:

The ballon bloow up. The vineger and the baking soda made a gas.

Next week: we waste more foodstuffs while learning about density.

Continuing my blogging project for 2011 where I do a science experiment per week with my seven year old daughter.

Following last week’s failed attempt to create a stalactite, Sam and I decided to go for something that looked a little more reliable. As a bonus, it involved FIRE. Here’s the equipment:

1. A shallow baking dish
2. A candle
3. Some colored water
4. Something small to set the candle in or on (I used a baby food jar)
5. A drinking glass or glass jar big enough to cover the above

I also had a fire extinguisher handy, just in case. Sam seemed hopeful that it would be needed.

Before we set fire to anything, though, I explained to Sam that fire needed two things to burn: fuel (like wood, gas, or a candle wick) and oxygen. The latter, I explained, was a gas comprising a good chunk of the air we breathe, along with nitrogen and a few other things. Nitrogen doesn’t do much in a fire, but oxygen, on the other hand, makes stuff burn REALLY good.

So I lit the candle, propped it up in in the little jar, then put the jar in the dish of colored water as you can see in the photo above. I then held up the drinking glass and asked Sam what she thought would happen if I put the glass over the candle, creating an airtight seal because of the water.

She paused a second. “The flame will go out!” she said.

“Why?”

“Because the fire will burn up all the air.”

So she HAD been listening. “Okay,” I said, “do you think it will go out right away? Good scientists are make their predictions as detailed as possible.”

She thought for a moment. “Ten seconds. No, 12 seconds. Then it will grow out.”

So, I asked Sam to write her prediction down in her journal.

Experiment 5: Brning oxagen. I prdekt that it will drn 12 sikints. Than it will go owt.

After she did this, I put the glass down, and after 16 seconds (according to my stopwatch) the fire dimmed and winked out.

Sam was interested in seeing the fire go out for no apparent reason, but seemed happy that her prediction was correct, if off by a few seconds. She claimed that the air was all gone inside the glass, but I explained that there was still some gas in there, but that the oxygen was pretty much gone, having been used up in the fire.

I asked her, though, to study the scene carefully and tell me if she noticed anything unusual about it:

Almost immediately she pointed and said, “The water inside the glass is higher!” I agreed that it was and told her to think back about what she had learned about air pressure in Experiment 1 and Experiment 3. Almost immediately she said that the air pressure inside the glass must be lower, and the air outside the glass must be trying to get in there and pushing the red water down and up into the glass.

Actually, I think it’s because the low air pressure inside the glass is sucking the liquid up but maybe it’s 6 of one half dozen of the other and I was pretty impressed by her quick answer. But she impressed me even more by asking a very astute question of her own: “How come, if candles need air to burn, they go out when we blow on them, like on a birthday cake? Why don’t they just burn more?”

At the risk of crooning about my kid, this struck me as a pretty damn insightful question, and I’m glad to see that she’s taking what she’s learning in these little experiments and trying to apply the facts to other phenomena in her world. Unfortunately the best answer I could come up with to her question was that when we blow out candles we’re blowing the air past the flame so fast that it doesn’t have a chance to react with the oxygen. However, some subsequent web searching suggests that this answer is, in fact, wrong or at least incomplete. The real reason candles go out when you blow on them is that the fast air is actually lowering the temperature around the flame enough to stop the reaction and put it out –a temperature high enough for ignition being the third requirement for flame that I forgotten to mention.

While I had to go back to Sam with this information and admit to not being as omniscient, it did give me a nice opportunity to explain the value of peer review to science. I think the laptop computer will be a standard piece of equipment to include with future experiments if for no other reason that we can take to the interwebs in the event of any more astute questions.

Well, 4 weeks in and we’ve got our first failed experiment. The idea was to make some homegrown stalactites and stalagmites, and here’s what was involved:

• Two jars
• Some yarn
• Two binder clips
• Baking soda
• Warm water

Sam filled both jars with warm water, then spooned baking soda into each one. She kept trying to lick her finger, coat it in baking soda, then lick it off, which I found gross but ultimately harmless. This made her want to eat more of it.

I had her keep stirring until no more baking soda would dissolve in the water.

Sam asked the pretty astute question of where the baking soda was going when it seemed to disappear, to which I replied “Uhhhhh…” as I frantically cast my memory back to my 10th grade science class and tried to remember. I gave her some kind of half-assed explanation about the baking soda molecules sticking to the ends of the water molecules and sort of fitting “in between” the water molecules. It turns out that this explanation was indeed more right than wrong, but it was all over her head in any case. So I focused on teaching her the concepts of a “solution” and “saturation.”

Anyway, after we had our warm water saturated with baking soda, I cut a piece of string, weighted the ends down with binder clips, and dropped one end in each jar:

I told Sam that I hoped the baking soda would form gather on the yarn and drop down the center to form a stalactite just like water and minerals do in caves over years and years. I asked her for her prediction:

I predekt it will grow 2 inches in 7 days.

Unfortunately things didn’t work out. After about 7 days we got this:

That’s got a pretty good head going on it, but the progress pretty much stopped there. I don’t know why –maybe we didn’t get enough baking soda in there, maybe the yarn wasn’t supposed to hang down into the jars that far, who knows?

Alas, this was Sam’s entry after 8 days:

It grow 0 inches in 7 days. Crest is grow on the yorn. It was wite.

Maybe we’ll have better luck next week.