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Is copper penny turning dark a chemical change?
Yes, the darkening of a copper penny is a chemical change. When copper is exposed to air and moisture, it reacts with oxygen and carbon dioxide, leading to the formation of copper oxide and other compounds that give the penny a darker appearance. This process alters the chemical composition of the copper, indicating a chemical change rather than a physical one.
Type of change that happens when you break a rock or freeze water?
Physical change: breaking a rock changes its physical appearance without altering its chemical composition. Freezing water involves a physical change where the water molecules rearrange to form a solid structure, without any change in the chemical composition of water.
When an object or solution changes appearance is it a chemical change?
Not necessarily. When ice melts into water, its appearance changes, since ice is a solid and water is a liquid, but that's a physical change. Both water and ice are H2O, so the chemical composition does not change, making it a physical change and not a chemical change. However, when iron reacts with oxygen to produce rust, its appearance also changes. You end up with iron oxide (a.k.a. rust) which has a different chemical composition than just iron and just oxygen. That's a chemical change. If you end up with something new that you didn't have before, it's a chemical change.
How the appearance of the pencil and the change in speed of the light waves relate?
The appearance of a pencil (e.g., bending when immersed in water) is due to the change in speed of light waves as they pass from one medium to another. This change causes the light waves to refract, leading to the appearance of the pencil being altered from the observer's perspective.
How does a penny affect water?
Supposidly, a bag of water with a penny in it keeps flys away. However, you really don't need the penny and a half filled bag of water will catch some flys.
When does Penny Marko make her first appearance in Spider-Man 3?
Penny Marko makes her first appearance a few minutes from Marko's first appearance and before he transforms into the Sandman.
Why does water stay long on a penny?
Water stays on a penny due to surface tension and cohesion forces. These forces cause water molecules to stick together and to the penny, creating a thin film of water that doesn't easily slide off. Additionally, the hydrophobic nature of the copper in the penny repels water to some extent, further helping the water to stay on the surface.
Is dropping a penny into a glass of water a physical change?
Yes
Is copper penny turning dark a chemical change?
Yes, the darkening of a copper penny is a chemical change. When copper is exposed to air and moisture, it reacts with oxygen and carbon dioxide, leading to the formation of copper oxide and other compounds that give the penny a darker appearance. This process alters the chemical composition of the copper, indicating a chemical change rather than a physical one.
Would a penny turn white if you bleach it?
Yes, soaking a penny in bleach will strip away the copper coating, causing it to turn white as the zinc core is exposed. However, this would significantly devalue the penny as it alters its appearance and composition.
How can water change the appearance of a river delta?
It breaks open rocks (erosion)
What happens when you put a penny in water?
When you put a penny in water, its density is greater than that of water, so the penny sinks. This is because the weight of the water displaced by the penny is less than the weight of the penny itself.
Why does a penny hold water?
sit the glass of water on the penny
What cleans a penny better?
A combination of vinegar and salt, or a paste of baking soda and water, can help clean a penny by removing dirt and tarnish. Gently rubbing the penny with either of these solutions can improve its appearance.
How could you explain that the change that take place in when salt is added to water is physical change?
It is a physical change because when salt is added to water,it is dissolved in it which only changes its physical appearance.
How many drops of water can a penny hold on its surface?
Water has a surface tension. When dropping water on a penny, people usually underestimate how much water the surface of a penny can hold. The surface tension of water is strong on a smaller surface, and when dropping water on the surface of a penny, towards 20 drops the water on the penny will look like it is bulging out a lot. It really depends, depending on which side of the penny you are using, it ranges from 6 to even 34 drops using a simple eyedropper. Because eyedroppers do not produce the exact same size of drops every time, the result is not very accurate. To be even more accurate, scientists use accurate distributing machines and a very new penny to determine how many drops of water it can hold without vibrations. There could be certain amounts of grime and dirt on a penny, depending on how old it is, which can affect how much water can be put onto it. Different types of water can also change how much a penny can hold. Tap water has certain amounts of chemicals in it, and that could also affect the weight and surface tension of the water on the penny. The height of which the water comes off from matters too, the more force of the water that comes down, the more likely the water on the penny is to splash and spill. The place the water lands on also has an effect on it. To be even more accurate, light has a mass. If light shines directly at the water on a penny, it could push it a tiny bit. This change is impossible to see, and it has basically no effect on the penny or water at all whatsoever. Remember, all tests may not be 100% accurate, and there may always be a chance that there is a better way to make a penny hold more droplets of water than the presumed "most advanced and accurate" way.
What is the control on the penny water drops experiments?
In this experiment, the control group would be the penny! The independent variable is the substance/water on the penny, and the dependent is how many drops the penny takes.
