Disco Fruit

This week we completed an investigation called disco fruit, we made predictions measured our solutions and prepared our equipment. For our method we added bicarbinate soda with warm water and stired until it dissolved. Then we added a handful of dried fruit and white vinegar, the fruit began to float to the top and sink as if they were dancing. We discovered that when the bicarbinate soda and white vinegar mix they create a gas, the gas bubble attaches to the fruit and it floats to the top, when it meets the cool air it pops and it sinks to the bottom, thus giving the impression of it floating.

The ice lifter

Big question can you lift an ice cube with a piece of thread? We made predictions then investigated this question, trying various techniques such as trying to make a hole in the ice or melting the ice using heat. None of our ideas worked, then we discussed how we melt ice on a winter’s day, we thought of salt.

Here’s our method

  1. Put the thread across the ice cube.
  2. Lift the thread off the ice cube, we found it doesn’t move.
  3. Put the ice across the thread again.
  4. Pour the salt on to the ice cube so that it covers the thread.
  5. Wait a few seconds.
  6. Now, take hold of each end of the thread and lift up the ice cube.

We discussed how we could make our method more accurate by specifying a measurement but then concluded the ice would have to be the same size too.

What we found out

The salt melts the ice on the top of the ice cube, making a small puddle of water. The rest of the ice cube is still very cold, so the water quickly freezes again around the thread. The thread is now stuck to the ice, so you can lift it up!

Capillary action – walking water

We started by putting 7 glasses on the counter. Fill glasses 1, 3, 5, and 7 most of the way up with water.

Next we add food coloring to the glasses:

  • 5-10 drops of red food coloring to glass 1 and 7
  • 15 drops of  yellow food coloring to glass 3
  • 5-10 drops food coloring to glass 5

Finally, take a paper towel and fold it in half width wise, fold it again, and again, and again. Now put one side of the folded paper towel into one glass and the other side of the paper towel in the next glass. Repeat with the remaining cups.

We watched the capillary action in motion as the water climbs up the paper towel. This is how the science experiment got its nick name Walking Water Science Experiment.

Capillary action is the process in which a liquid moves up something solid, like a tube or into a material with a lot of small holes. This happens when 3 forces called cohesion, adhesion, and surface tension work together. Water molecules are considered cohesive (sticky to each other) and they adhere (stick) to the paper towel. As one water molecule moves up the paper towel it pulls the other molecules with it. The molecules pull each other along like a drawstring.

Exciting electricy

This week, we had the challenge of making a lightbulb work, we were given all the equipment and had to figure out how to make a circuit. We discussed all the different types of energy and what we might need. We worked in small groups to create the cicuit, we then had the challenge of adding motors or another light build.

Finally, we learnt the correct symbols and drew a circuit.

Clean water distillaion

We each built own distillation to make dirty water clean, we used carbon, sand, sediment and filter paper to filter out the dirt and mud.

Lava Lamps

Today we investigated liquid density by making a lava lamp.
We used
  • A bottle of water
  • vegetable oil
  • water
  • food colouring
  • salt

Method

  • Fill bottle 2/3 with water
  • Add a few drops of food colouring
  • Fill the bottle rest of the way with vegetable oil, leaving a bit of space at the top
  • Add in a table spoon of salt on to the oil- The first bubbles form as the salt sinks and releases air bubbles. Once it reaches the bottom, oil blobs move as the salt sinks and releases air bubbles.
  • add more salt to repeat the effect.

How it works

The homemade lava lamp works because oil is less dense than water and floats on top of it. Salt is more dense than either oil or water, so it sinks when you add it to the bottle. Oil blobs stick together and slowly return to the top of the glass.