Embedded Files
How Many Drops Can Lincoln Hold?
How Many Drops Can Lincoln Hold?
Materials:
Penny
Water
Pipette/Dropper
Paper Towel
Directions:
Fill the pipette/dropper with water
Use the pipette to place one droplet of water onto the penny at a time
Keep track of how many droplets of water you have placed onto the penny using tally marks on the table below
Once the water spills off the penny, use a paper towel to wipe off the penny and your surface
Repeat steps 1-4 two more times for a total of 3 trials
Add up the number of tally marks from the 3 trials and divide the sum by 3 (This is the average!)
Why did we perform the experiment multiple times?
Trials are important because they help reduce any errors that could have been made during the experiment. After all, even if you mess up once, the other correct trials can ‘average out’ the error!
Where is the chemistry?
Did you notice that a 'bead' of water formed on top of the penny's surface? This occurs due to surface tension. Surface tension is a property of a liquid that happens when the molecules of a liquid are attracted to each other (or stick together). This property causes the water to form a bead or dome-like shape on top of the penny.
Table: Click on the table and make a copy, or write the table on your own paper!
Share your results with us using this link: https://forms.gle/ZupyMs1wXKjJAask6
Magic Soap
Magic Soap
Materials:
Water
Pepper
Dish soap
Bowl
Steps:
Pour water into a bowl (don’t spill!)
Sprinkle pepper across the surface of the water
Squeeze a small amount of dish soap onto your finger
Dip your finger into the bowl and watch the magic happen!
Explanation:
Pepper floats on top of the water because pepper is hydrophobic, which means it’s not attracted to or ‘scared’ of water. Also, the water molecules line up together to form a layer that creates surface tension. Surface tension is a property of a liquid that happens when the molecules of a liquid are attracted to each other (or stick together) and resist anything that disturbs this attraction. The pepper can float because it is light, so it will not break the attraction between the water molecules, or the surface tension.
Now, why did the pepper move to the side of the bowl? Well, soap can BREAK the water’s surface tension because it is a surfactant! When you dip your finger into the bowl, you break the water’s surface tension at the place where you touched the water. But, the water wants to maintain its surface tension, so it keeps its surface tension at places far away from the soap, which moves the pepper to those places.
Invisible Ink
Invisible Ink
Materials:
Lemon juice (with parent supervision!!)
Water
Small paint brush
Bowl
White piece of paper
Light/lamp
Steps:
Ask a parent to squeeze a lemon into a bowl and add a few drops of water to make lemon juice
Take your small paintbrush and dip it into the bowl (make sure not to splash the lemon juice!)
Paint your secret message onto the white paper using your paintbrush. You may need to dip your paintbrush into the lemon juice a few times to finish writing your message.
Let the paper dry until you can’t see the lemon juice on the paper (it’s invisible!)
With parental supervision, hold up your paper to a light or lamp (not too close) and watch your message be revealed!
Explanation:
Lemon juice is clear at room temperature, especially when mixed with water, because it is made up of mostly carbon compounds which are transparent at room temperature. However, when you heat up the lemon juice by holding the paper up to a light, the carbon molecules in the lemon juice break down and react with the oxygen molecules in the air. The reaction (oxidation) causes the molecules in the lemon juice to turn BROWN and your message to be revealed!
Oobleck
Oobleck
Materials:
Cornstarch
Water
Bowl
Spoon
Measuring cup
Directions:
Measure out one cup of cornstarch and pour it into a bowl
Measure out one cup of water and pour it into the same bowl with the cornstarch
Use the spoon to mix the water and cornstarch together
Place the spoon off to the side, and try touching the mixture quickly. What happens?
Try touching the mixture slowly. What happens?
Explanation:
Oobleck is a type of suspension. A suspension is a mixture where a solid is spread throughout a liquid without dissolving in it. In this experiment, the solid is the cornstarch, and it is being suspended in the water. This allows the substance to act like a liquid when touched slowly with little force, and act like a solid when touched quickly with more force.
Instant Ice
Instant Ice
Materials:
Plastic water bottle
Freezer
Timer
Bowl (preferably ceramic)
Directions:
Place the plastic water bottle and a ceramic into the freezer
Set a timer for 45 minutes. After 45 minutes, the water inside the bottle should still be a liquid but cold.
Take the water bottle and bowl out of the freezer
Slowly pour the water out of the bottle onto the upside-down bowl and watch the magic happen!
Why did these ice crystals form?
Explanation: After 45 minutes, the water is still a liquid, but it is nearly frozen. If it were left in for 10 more minutes, it would be completely solid! Because the bowl is cold, the water chills just enough for the crystals to form once it hits the bowl. This is how ice crystals form in real life as well! For example, icicles form when an almost-freezing water droplet reaches a freezing-cold surface or freezing-cold air, forming an icicle or crystal.
Page updated
Google Sites
Report abuse