# DIY Density Column

We know that density depends on mass and volume of a substances. We can easily see differences of density when comparing anything to the air in our atmosphere. But what about common liquids compared to each other? Lucky for you, that’s exactly what we did. In this DIY experiment we poured seven liquids into one container to see what would happen.

The seven ingredients that we are using are honey, corn syrup, maple syrup, whole milk, dish soap, water, and vegetable oil. Just to spice things up we added a bit of food coloring to the water. If you pour them in order of most dense to less dense, they do a really good job in staying separated. However, the food coloring that was added to the water turned out to be more dense than water and the dish soap and started mixing in with the milk layer!

Ideally, if we mixed up the density column and incorporated all of the ingredients together, after a few hours we would be able to get the layers back. However, the dish soap will react to the milk and oil, making separation impossible for every single layer.

We tried this experiment with just seven liquids. Can you think of other liquids to try adding? When you do this at home, try dropping in different household items like paper clips, bottle caps, or ping pong balls to see how their densities compare. For more all things density, check out Will it Float?

# Static Electricity: It’s Shocking

Have you experienced rubbing your feet on carpet just to reach out to someone and give them a little zap? Or slide down a plastic slide and gotten a nice jolt from it?  What about rubbing a balloon on your head to make your hair stand on end? A Van De Graaf generator is a tool to experience even more static electricity!

Static electricity is an imbalance of electric charge on a surface. The charge remains imbalanced until there is an electric current or an electrical discharge. A Van De Graaf generator works much the same as rubbing your feet on the carpet to move electrons throughout your body. A moving belt in the generator accumulates an excess of electric charge which is then transferred to a large hollow sphere.

The sphere builds up  free electrons which all have a negative charge. When too many negative charges are near one another they will start to repel. If you force enough of them onto a single surface you can build up enough charge to see an effect such as your hair standing on end, pie tins flying off due to repulsion, or a shock!

Electricity will  take the path of least resistance and wants to be neutral. As shown here, a fun and safe way to manipulate the static electricity is with a grounding rod. The grounding rod neutralizes the Van De Graaf generator by moving all of the excess charge from it to the surface of the Earth.

You can also neutralize the generator without a grounding rod. Humans are decent conductors of electricity. This means that your body could act as a grounding rod too. Just remember that you have one thing that a grounding rod does not…NERVES. If you decide to ground the sphere, brace yourself for quite the jolt!

Written by: Mimi Garai

# Happy Earth Day

At AstroCamp we take pride in living in the beautiful mountains and wilderness of southern California. We appreciate the deer, squirrels, rabbits, coyote, pine trees, boulders and so much more. One way that we show this appreciation is by using natural and renewable energy whenever possible.

Solar energy is a great renewable resource that we have put into use in a fun way. It turns out that if you have the right equipment and enough sunshine, you can heat up water using our own sun’s radiation.

This is a solar water heater. The way it works is quite simple. You pour the water at the top, it goes through the pipe, and comes out the bottom. Just by the water passing through the pipe we can increase the temperature by more than 50 degrees! But how?

The first step is the pipe itself. It is made of copper which is a great conductor of heat, meaning that heat can be easily transferred throughout it. The second step is to paint it black. Black pigment absorbs many wavelengths of light which helps to heat up the pipe. The third step is the plexiglass covering. Plexiglass allows visible light to pass through it, but is too thick for infrared light, or heat, to escape it. When, the visible sunlight passes through the clear covering, it loses some energy, turning the visible light into infrared light which is then trapped under the covering.

We have taken this small solar water heater and turned it into a big idea. AstroCamp uses this technology to try to reduce our energy waste by heating our pool with a similar system! Water from the pool is pumped up to the roof of our gym, passed through a black copper pipe and is then pumped back into our pool. Thanks to the sun’s energy we have a bunch of happy campers!

Happy Earth Day from all of us at AstroCamp to you!

# Lift: The Key to Flight

A Boeing 747 weighs around 750,000 pounds, so how does it manage to get off the ground? It’s all thanks to a force called lift and something you may be familiar with from other AstroCamp videos: Bernoulli’s Principle.

Lift is just the name for the force pushing an object up into the air, but Bernoulli’s Principle is a little more involved. It states that whenever a flowing substance like air increases in speed, the pressure inside the flowing portion decreases. This means that if the air flowing along one side of a surface is moving faster than on the other side, there’s higher pressure on one side, pushing the surface. We can see that with Lin’s sheet of paper; blowing on only the top side causes the now higher pressure below to push up on the paper, generating lift.

The same concept applies with the wings of a 747, though with one important difference: there’s airflow along both sides of the wing. However, airplane wings are designed to provide some air resistance along the underside, so the air moving along the top is still flowing faster, generating lift.

# Non-Newtonian Fluid: Oobleck DIY

Here is a great DIY experiment that you should definitely try at home.

Oobleck, a name based off of Dr. Seuss’s “Bartholomew and the Oobleck”, is just one such example of a Non-Newtonian fluid. Try this DIY out for yourself. All you’ll need is about 1.5 cups of cornstarch and one cup of water.

Most substances and materials that exist can be put into one of the four states of matter: solid, liquid, gas, and plasma. However, there are some mixtures that can’t fall into those categories, or that can be in more than one of them. Non-Newtonian fluids are one such thing. A Newtonian Fluid is a liquid that has an expected viscosity, or flow rate even when under stress such as a change in pressure. A Non-Newtonian fluid has a non-linear change in viscosity when introduced to a stressor, meaning that it will act a bit weird and unexpected.

When left alone, this mixture acts as a liquid. It has a definite size, but takes the shape of it’s container. However, when you apply a sudden force, such as hitting it or squeezing it in your hands, then it’s viscosity greatly increases. It acts as a solid, having a definite size and its own shape.

# Behind the Scenes with a Lighter Flame Float

It’s a classic trick to make a lighter flame float, but how does it actually work? As it turns out, the secret can be found on your desk: a ballpoint pen. Though the key to the trick may be simple, there’s some really cool science making it happen. Follow along with us and we’ll show you how and why this works. Be careful though, you will be handling fire.

The first thing you need to do for this is take apart your pen, leaving nothing but the tube of ink behind. When doing this, it’s a good idea to have a paper towel down to catch any ink that leaks out of the tube.

Then, collect some ink with an unfolded paper clip and cover the nozzle inside the lighter where the fuel comes out. This ensures the fuel and ink will mix, a vital part of the experiment. This was the most direct means of mixing the ink and fuel for our disposable lighter, but other lighters have more direct means of accessing the fuel reservoir and those should be taken first.

Once you’ve mixed the ink and the fuel, your flame should appear to float over the lighter. Depending on how well the ink and fuel mix, this effect could be brief, so watch carefully. We know how we get it to float now, but why does adding ink to the lighter fuel make it float?

Normally, butane lighter fuel releases blue light when burned, but the addition of the ink pushes that energy release into the ultraviolet part of the spectrum. Since our eyes can’t see UV light, the portion of the flame from the burning ink appears invisible, producing the illusion that the rest of the flame is floating.

# Will it float? Experimenting with Density

Have you ever wondered exactly why a boat floats or why rain falls down and not up? It all has to do with density! Density is a measure of how much mass there is in a given volume, or rather how much stuff you have in a certain place. It determines whether something sinks or floats when compared to something else.

Since, we are talking about sinking and floating, let’s use the most obvious example we have, water! Water has a density of 1g/cm3. That means if anything is less dense, it will have less stuff in that same volume. A great example of that is ice which has a density of 0.9167g/cm3, which is why your ice floats in a glass of ice water. Moreover, air floats on top of water because it’s density is roughly 0.001225g/cm3.

Here are two experiments that clearly shows a difference in density. For the first experiment we will use these two silver spheres have the same mass, but very obviously different volumes. When I drop them in air, it is hard to tell the difference in densities, but when I move it to water the difference is clear! The smaller sphere has the same amount of stuff as the larger sphere, but in a smaller space, therefore it is more dense and will sink. The larger sphere floats because it’s mass is not large enough to displace the same volume of water.

Now take two cans, one of Coke and one of Diet Coke. These clearly have the same volume, but do they have the same density? It’s pretty hard to tell in air, so let’s take it to water. Drop them both in at the same time and watch what happens! The can of Coke will sink to the bottom, while the can of Diet Coke will float. So what’s the difference? A can of coke has about 39 grams of sugar which is about 10 teaspoons full. Where as a can of Diet Coke doesn’t have any. Instead, Diet Coke has an artificial sweetener in it called aspartame, that has the same amount of sweetness in it as regular Coke, but only uses as much as a few drops of it. So regular Coke will sink because it quite literally has more stuff in it.

So, things don’t float or sink due to how much they weigh, but rather it’s due to how much matter they have packed into a certain space. Can you think of other examples of things that share a characteristic but have different densities?

# DIY: Clock Reaction Experiment

Check out this tricky science for April Fools, and no it’s not magic! This is a clock reaction, meaning that it takes some time to see the effects of the reaction. However, there are actually two reactions taking place.

What we used:

2. In the first beaker add ½ of a tsp of sodium Iodate.
3. To the second beaker add ¼ tsp sodium sulphide, ½ tsp citric acid, and 12 drops of a starch indicator.
4. Make sure to stir well, so that the solutes are dissolved.

Now you are ready to mix it all together. For a little added drama, try pouring them back and forth into each other.

In the first, slower reaction the sodium iodate reacts with the sodium sulphide and turns iodide into triiodine. The triiodine then reacts with the citric acid and the result is that the solution stays clear. But, when all of the citric acid is used up, then the second reaction can start! This quicker reaction turns triiodine back into iodide and there is a very evident color change. The solution turns dark blue, indicating when the freed iodide is in the presence of starch.

Now it’s your turn to trick your friends this April Fools! Try this out at home and see if you can catch them off guard in mixing two clear liquids together.

NOTE: Use adult supervision. Many of the chemicals used in this experiment are toxic. Do not consume, but do have fun! Happy April Fools Day from all of us at AstroCamp.

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