Good science at home does not need a kit. It needs a question, something to try and an adult who says “what do you think will happen?” before saying anything else. Here are five experiments that use things from the kitchen, each with what happens and why.
A note on safety: an adult should be in charge, nothing in any of these is for eating, and hands should be washed afterwards. Do them over a tray or a sink if you can.
The three questions
Before the experiments, here are the three questions that make any activity into science. Ask them every time:
- What do you think will happen? (A prediction. A wrong guess is just as useful as a right one.)
- What do you see? (An observation. Ask for details: colors, sizes, how long it took.)
- Why do you think that happened? (An explanation. “I don’t know” is a fine answer; “let’s try it again with one thing changed” is a better one.)
1. Sink or float
You need: a bowl or sink of water and a handful of small objects: a coin, a cork, a grape, a plastic spoon, a metal spoon, a lump of modeling clay.
Do it: For each item, predict and then test. Sort them into “sinks” and “floats”.
What happens: Things sink or float depending on their density, which means how much stuff is packed into how much space compared with water. Weight alone does not decide it. A big, heavy log floats and a tiny coin sinks.
Try this: Roll the clay into a ball and drop it in: it sinks. Now shape it into a little boat with high sides. It floats, because the shape pushes aside more water, so the boat is, on the whole, less dense than water.
2. Walking water
You need: three clear cups, red and yellow food coloring, water and strips of paper towel.
Do it: Fill the first and third cups with water, and color one red and one yellow. Leave the middle one empty. Fold paper towel strips and stand each one with one end in a colored cup and the other end in the next cup. Wait a few hours.
What happens: The water climbs up the paper and drips across, and the middle cup slowly fills with orange. The water moves because paper is full of tiny gaps, and water is attracted to the fibres and to itself. This is called capillary action. It is how plants draw water up from the soil.
Ask: “What color do you think the middle cup will be?” and “How long do you think it will take?”
3. The ice race
You need: two ice cubes of the same size, two saucers and some table salt.
Do it: Put one cube on each saucer. Sprinkle salt on one. Watch both for a few minutes.
What happens: The salted cube melts faster. Salt dissolves in the thin layer of water on the surface of the ice and lowers the temperature at which water freezes. So at the same room temperature, the ice with salt on it melts. This is why roads are salted in winter.
Ask: “Is the salt making it hotter?” (No, it is making it easier to melt.) “What would happen with sugar?” Then try it, and see what is the same and what is different.
4. A bean in a bag
You need: a zip-top bag, a paper towel, a few dried beans (not roasted) and tape.
Do it: Fold the paper towel to fit the bag, dampen it so it is wet but not dripping, and slide a bean or two between the towel and the bag. Seal the bag and tape it to a window. Check it each day.
What happens: In a few days the bean swells and cracks, a root grows down first, and then a shoot grows up. Seeds contain stored food, so they do not need soil to start growing. They need water and warmth.
Ask: “Which part comes out first?” and “Which way does the root go, even if we turn the bag around?” Draw it every day, so your child can see the changes over time.
5. Shadow tracker
You need: a sunny day, a sheet of paper, a pencil stuck upright in a lump of clay and a marker.
Do it: Put the paper on a flat, sunny spot, such as a patio or a windowsill, and don’t move it. Every hour, mark where the tip of the pencil’s shadow falls and write the time.
What happens: The shadow changes length and direction through the day. It is longest in the morning and evening and shortest around the middle of the day. The sun does not move across the sky so much as the Earth turns, which changes the angle of the sunlight. People have used shadows to tell the time for thousands of years.
Ask: “Where do you think the shadow will be at lunch?” and “What if we did it again in winter?”
Keep a science notebook
Give your child a notebook, and let them draw what they predicted and what they saw, and write a word or two. Children who record what they see learn that science is about evidence, not just fun.
When it goes wrong
Sometimes an experiment will not work. The beans do not sprout, or the shadow is hard to see. That is science too. Ask “what might we change?” and try again. Not getting the expected result and working out why is how scientists learn.
More to explore
Tutorpip’s science episodes, from Pre-K to Grade 6, follow the same pattern: a question, a prediction, something to try and an explanation. You can see how the tutor works in a free lesson.