- 1. How to grow crystals
- 2. Lime breath
- 3. Chromatography
1. How to grow crystals
Make a saturated crystal solution to grow crystals. These beauties take several days to grow, but they’re worth to wait!
Things you’ll need: A beaker, Things that dissolve in water, petri dishes, a microwave, a spoon, and petri dish lids.
- Prepare things that dissolve in water (for example salt, sugar, borax, copper sulphate, etc.)
- Pour only one of the things (let’s use borax) that dissolve in water into the beaker.
- Pour water into the beaker with the borax.
- Mix the solutions until it cannot dissolve.
- Put the beaker into a microwave then heat it for 40 seconds.
- Take the beaker out of the microwave.
- Pour the solution haft way in the petri dish.
- Close the petri dish haft way with the lid.
- Wait 7 days, after that, you’ll see tiny crystals in the dish.
You can use the list above to change the crystals by doing the whole experiment and using different chemicals. The small crystals formed in the petri dish because of nucleation. A few borax molecules found each other in the solution and joined together in a crystal formation. Other borax molecules continued to join until enough had gathered to become a visible crystalline solid. Chemists refer to this as a crystal “falling out of” the solution. If you left these crystals in the solution, they’d continue to grow, but they wouldn’t get very big because they’d all be competing for the remaining borax molecules in the solution.
2. Lime Breath
Turn a clear solution cloudy white with just your breath. This experiment is common, fun, and easy. I recommend doing this experiment first! [Click on image to make bigger]
Things you’ll need: a straw, a funnel, a 250ml flask, a solid rubber stopper for the flask, a spoon, calcium hydroxide, filter paper, and water.
- Put 3 level scoops of calcium hydroxide in the flask, fill to the 250ml line with water, and tightly insert the stopper. (I think that I put too much calcium hydroxide in the flask, but at least I told you the steps… ).
- Shake vigorously for 1-2 minutes, and then let it stand for 24 hours. (The chemical won’t fully dissolve). And the solution will be clear.
- Cut ¼ of the filter paper, the paper should look like pac-man. After that, bring edges together to make a cone shape, and then, put the cone into the funnel.
- Being careful not to stir up the sediment, slowly pour the solution off the top through the funnel to the beaker.
- Look through the top of the beaker and notice the color of the liquid. Put a straw into the beaker, holding it near the surface of the liquid.
- Blow air through the straw for a minute and the liquid should turn cloudy white.
Your breath contains carbon dioxide gas. The Limewater, a solution of water and calcium hydroxide reacts with carbon dioxide, forming calcium carbonate. Since calcium carbonate is not water-soluble, it precipitates out, leaving the white matter you see in the beaker. So there was not only a color change from clear to cloudy white when you added carbon dioxide but there is also a change in states. The chemical reaction is: Ca(OH)2 + CO2 → CaCo3 + H2O
Ca(OH)2 is calcium hydroxide; CO2 is the carbon dioxide from your breath. This reaction results in calcium carbonate (CaCO3) and water (H2O).
Did you know that the color black is made up of many different colors? Do this experiment to find out.
Things you’ll need: A beaker, a long pencil, filter paper, a black washable marker or felt-tip pen, a clip, and water.
- Cut a piece of filter paper into a square to fit in the beaker.
- Draw a pencil line across the narrow end of the square about 1 cm from the bottom as shown in the picture.
- Draw a small dot with the black marker on the pencil line.
- Use a clip to attach the paper to the pencil. Set the pencil across the top of the beaker. Adjust the paper until it hangs down without touching the sides or the bottom of the beaker.
- Carefully pour water into the beaker until it just touches the bottom of the paper strip, and make sure the water level is below the marker spot.
- The water will begin to travel up the paper.
When the water nears the top of the paper, remove the paper from the beaker and let it dry.
The series of colors you see is called a chromatogram. As the water travels up the paper, it dissolves the ink and pulls it up the paper too. The black ink is actually a mixture of several different pigments or coloring agents.