“I believe that people should be passionate about things that affect their life”
A/B: Mystery Liquids Part I And II
Use your senses to try and predict what the water-based liquids are.
The mystery liquids will be left out for at least two days. What do you predict will be left in the petri dishes.
Liquid U : salt water
Liquid W 100% orange juice (natural)
Liquid X tapwater
Liquid Y Coca Cola
Liquid Z Vinegar
C: Salt Water vs Fresh Water
- Put _lime__ in the fresh water and in the salt water.
The lime sinks in freshwater but floats in saltwater.
Deduction: saltwater is denser than freshwater (saltwater pushes up the lime more than freshwater does, so the lime floats in saltwater.
- Put one electrode on one side of the Petri dish and another electrode on the other side
Saltwater is more conductive (of electricity) than freshwater.
Fact: pure 100.00% H2O barely conducts electricity.
D: Can metal stay on top of water?
1. Gentle place a staple on top of the water.
2. Drop a staple into the water
The staple sits on top of the water (if placed correctly). But if the staple is dropped or pushed under the surface of the water, it sinks.
There is something happening on the surface of the water that pushes the paper clip up.
Water is viscous: it sticks to itself. There is surface tension on the surface of the water. Water is attracted to itself. When the staple pushes down on the water, the water tension pushes up on the staple.
E: When does 10 + 10 20?
1. Use the dropper to measure out 10.0 mL of water in both 10.0 mL measuring cylinders.
2. Add the volumes of water to a small beaker.
3. Pour the water back into the measuring cylinders.
Use the same method as part 1 except measure alcohol in one of the cylinders (and water in the other).
The final volume of the water ethanol mix is less than 20mL (between 19.0 - 19.6mL).
The volume decreased because ethanol occupied spaces between the water molecules.
Fact: when water freezes, the spaces between the water molecules increases. That’s why ice is bigger than the water it’s made from.
F: Sometimes Water Has Secrets
1. Write a secret message using the dropper, the water-based liquid and a small piece of paper.
2. Reveal a message from the other class by heating the paper.
Heat causes the paper exposed to the liquid to change to a darker colour.
There are molecules in the water-based liquid that change colour (undergo a chemical reaction) when heated.
Where’s the freshwater?
Making water cycle diagram
Carbon Cycle examples