Water Displacement with Pirates

 

We spent a sunny day out at a boat landing in the city to learn about water displacement and buoyancy. Skylar spent the day before creating his own version of a pirate ship to help with the lesson. We ended the class lesson by throwing "cannonballs" at the poor ship, but it held strong and didn't take on any water, or sink.

Using the Sun to Tell Time

Illustrations via Tanglewood Hollow

Homemade Fingerprint Powder

Have you ever wanted to be a forensic specialist and investigate a crime? As unfortunately as the world is, we can't get away from crime and heinous actions of others. With these crimes, forensic and crime scene investigators go to these crime scenes with a tool to find out if the criminal left any fingerprints that could link them back to their evil deeds. This tool is fingerprint powder. Although, the process to create fingerprint powder at home is a bit different than what is actually used, it still serves the same purpose in identifying fingerprints on objects. We recreated our own fingerprint powder and experimented on glasses to lift fingerprints off the surface. This simple fingerprint powder can be recreated at your own home and you can play around to see what surfaces you can lift fingerprints from and identify whose print is whose. Be careful, though, this powder will stain surfaces. Glass is a preferred surface.

• Materials Needed:
• 1. Cornstarch
• 2. Measuring Cup
• 3. Candle
• 4. Porcelain dish or metal spoon
• 5. Knife
• 6. Small bowl
• 7. Small paint brush
• 8. Small funnel
• 9. Small jar with lid
• 10. Patience

Start by using a candle, bowl, and a metal spoon. Place the candle in the bowl and light. Using the flame of the candle (in a very well ventilated area, preferable outside), place the spoon over the flame and allow it to burn the back of the spoon. After a short time we will create soot on the back of the spoon. Scrap the soot off each time it's created. We will need about a tablespoon to 1/4 a cup of soot, so this takes some time. We did our collection over a period of several days. 

Depending on how much soot you have created you need to mix the same amount of corn starch with the soot powder. So, say you have a tablespoon of soot, mix that soot with a tablespoon of corn starch. 

Next, have friends or family to touch their forehead and then touch a glass surface. We used drinking glasses here, but you can also touch countertops, sliding glass doors, windows, and even plastic bottles, or soda cans. Just remember, whatever you use for your surface, make sure it's easy to clean up afterwards.

Once they place their fingers on the surface you can see the fingerprints, but only faintly. 

Next step is to use your newly created fingerprint powder and using a soft paint brush, lightly brush the powder over the fingerprint. Be careful not to press too hard, or you will disturb the oils in the print. Once you lightly lay a layer over the print, tap the glass to remove the excess powder.

Next step is to use clear packing tape, of course any clear, wide tape would work, we just happened to have clear packing tape on hand. You want to use the tape and place it directly over your fingerprints. Be careful not to press down too hard as you could damage the print, but a light rubbing over the top of each one is going to help with the lifting process of the print with the fingerprint powder.

Next step is to lift the prints and place them onto white paper. We used small post-it notes to adhere our prints, but computer paper would work, too. Place your tape down on the paper and press lightly. Here you can view your prints without worrying about messing them up any further. If you did several people's prints, it's interesting to see the difference in each person's print. Make note of how different they are, and if these prints were to be gathered for criminal reasons, how would each person be able to be caught, or eliminated? 

Be sure to save the rest of your fingerprint powder to use again in the future. We stored ours in a small corked glass jar along with the funnel and the soft paint brush. You can store yours in anything that seals and is able to be put away without spilling. Remember, this fingerprint powder has soot in it and will stain most surfaces. 

If you create this project we'd love to see it. Tag #rainvalleyredsnails on Instagram or Twitter, so we can see your fingerprint creations.

Vinegar and Water Egg Experiment

 

This week we did an raw egg experiment with vinegar and water and seeing exactly what and why acids and bases work against each other. With water not having acidity the egg shell, which is mostly calcium (another base) it doesn't break down the shell. But, with vinegar being an acid, it works to dominate the egg shell and break down the base and works against it. 

We soaked raw eggs in water and vinegar for a week in separate jars and waited. After the week was up, we removed them and took note of how differently the shells were manipulated by each liquid. Interestingly enough, you could do this same experiment with soda, orange juice, or any liquid that has acid in it. You can also see the reaction with baking soda and vinegar. (As you can see from the videos below, the vinegar dissolved the outer shell and left just the membrane of the egg and it was strong enough to bounce on the floor.)

Egg Experiment (Vacuums and Air)

We've been doing a lot of science experiments lately in the RVRS homeschool classroom. With Skylar being in the eleventh grade, there's so many things I want to fit into our schedule, but have to pick and choose which ones will give them best educational experience. One of the experiments is using a hardboiled egg, a match, and a bottle to create a vacuum with the change in air pressure with the heating and cooling air inside and outside the bottle. Here is our homemade vacuum egg experiment and how you can duplicate the same experiment in your own home.

Start with boiling an egg to hardboiled status. About five minutes for most eggs.

Next, grab a glass bottle and make sure the opening is wide enough to just have the hardboiled egg sit comfortably on top of the bottle opening.

Next, light a match and allow to burn for about three seconds. Drop the match into the bottle and place the hardboiled egg on top. And, wait. The match should burn out and you are left with the hardboiled egg being pulled inside of the bottle.

Once the air pressure inside the bottle changes from the outside air, POP goes the egg inside the bottle. But, why does this happen?

Heat causes the air inside the bottle to expand. When the egg is placed on top of the bottle, this causes the oxygen for the fire to burn to be cut off. Therefore, the fire goes out. When the fire goes out, this causes the air inside the bottle to contact as the air outside the bottle is trying to compete with the air inside the bottle. It has to remove what's blocking that process, so the air outside pushes on the egg to meet with the air inside. This is how vacuums are created (in theory). Of course a vacuum is the lack of all air, so in turn, we create a "mini" vacuum by playing with fire.