Fun with science

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An experiment with liquid density.

Text of Fun with science

  • 1. Cam-Tu Diep

2. ~Around 2/3 to of the earth surface iscover with water. ~Did you know that our bodies are madeup of 65% water. ~75-80% of the human brain is water. ~The chemical name for water is H(2)O -which represents two Hydrogen atomsand one Oxygen atom. 3. 1) Solid - frost , snow, ice.2) Liquid water, rain.3) Gas - water vapour. 4. Density is mass (howmany atoms are in anobject) divided byvolume. The more atoms aliquid contains thedenser it will be. 5. Regular Water Salt Water => Water + Salt Sugar water => Water + Sugar Question & hypothesis: Will adding salt makewater more dense? Will adding sugar makewater more dense? Which is denser, sugarwater or salt water? Write down what youthink will happen to the density of water ifyou add salt or sugar. *Hypothesis: is a proposed explanation for a phenomenon. 6. Fill three beakers with 150 ml (2/3 cup) of water. Addfood coloring to make blue, red, and green water. Add 2 teaspoons of salt to the blue beaker and stiruntil the salt is dissolved. Add 2 teaspoons of sugarto the yellow water and stir until it is dissolved. Try putting a raisin in each of the beakers. Does itfloat? Remove the raisins with a spoon. Pour some of the blue (salty) water into the graduatedcylinder. Using the pipet, slowly add the yellow(sugar) water one or two drops at a time. Recordwhich sinks to the bottom and which floats on top. Add the red (pure) water drop-by-drop to the othertwo and record what happens. 7. Were your predictions correct? Did addingsalt and sugar to the water make the watermore dense or less dense? Which was moredense, the salt water or the sugar water? 8. Water Facts and Trivia 9. H+ (aq) + OH (aq) H2O acid + base salt + water CH3CO2H + NaHCO3 => CH3CO2Na +H2O+CO2 (formed from unstable carbonic acid H2CO3) Vinegar + baking soda =>Sodium acetate +water + carbondioxide Sodium bicarbonate and vinegar => Sodium acetate and waterand carbon dioxide NaHCO3 + CH3COOH => CH3COO-Na+ + H2O + CO2 The positive ion from a base forms a salt with thenegative ion from an acid. 10. Baking soda is made of sodium bicarbonate.Vinegar is an acid (acetic acid). When the twocombine, they create a chemical reaction(Acid-base Reaction). Vinegar causes thebaking soda to break down, creating adifferent substance. This gas is called carbondioxide. It is less dense than the air around it.The carbon dioxide rises into the balloon,inflating it.